com.espertech.esper.core.StatementLifecycleSvcImpl.java Source code

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/**************************************************************************************
 * Copyright (C) 2008 EsperTech, Inc. All rights reserved.                            *
 * http://esper.codehaus.org                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esper.core;

import com.espertech.esper.client.*;
import com.espertech.esper.client.annotation.Hint;
import com.espertech.esper.client.annotation.Name;
import com.espertech.esper.client.soda.EPStatementObjectModel;
import com.espertech.esper.collection.Pair;
import com.espertech.esper.epl.annotation.AnnotationUtil;
import com.espertech.esper.epl.core.MethodResolutionService;
import com.espertech.esper.epl.core.StreamTypeService;
import com.espertech.esper.epl.core.StreamTypeServiceImpl;
import com.espertech.esper.epl.expression.*;
import com.espertech.esper.epl.named.NamedWindowService;
import com.espertech.esper.epl.spec.*;
import com.espertech.esper.event.EventAdapterService;
import com.espertech.esper.event.EventTypeSPI;
import com.espertech.esper.event.NativeEventType;
import com.espertech.esper.event.map.MapEventType;
import com.espertech.esper.filter.FilterSpecCompiled;
import com.espertech.esper.filter.FilterSpecParam;
import com.espertech.esper.pattern.EvalFilterNode;
import com.espertech.esper.pattern.EvalNodeAnalysisResult;
import com.espertech.esper.pattern.EvalNodeUtil;
import com.espertech.esper.util.ManagedReadWriteLock;
import com.espertech.esper.util.UuidGenerator;
import com.espertech.esper.view.ViewProcessingException;
import com.espertech.esper.view.Viewable;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.lang.annotation.Annotation;
import java.util.*;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * Provides statement lifecycle services.
 */
public class StatementLifecycleSvcImpl implements StatementLifecycleSvc {
    private static Log log = LogFactory.getLog(StatementLifecycleSvcImpl.class);

    /**
     * Services context for statement lifecycle management.
     */
    protected final EPServicesContext services;

    /**
     * Maps of statement id to descriptor.
     */
    protected final Map<String, EPStatementDesc> stmtIdToDescMap;

    /**
     * Map of statement name to statement.
     */
    protected final Map<String, EPStatement> stmtNameToStmtMap;

    private final EPServiceProviderSPI epServiceProvider;
    private final ManagedReadWriteLock eventProcessingRWLock;

    private final Map<String, String> stmtNameToIdMap;

    // Observers to statement-related events
    private final Set<StatementLifecycleObserver> observers;

    /**
     * Ctor.
     * @param epServiceProvider is the engine instance to hand to statement-aware listeners
     * @param services is engine services
     */
    public StatementLifecycleSvcImpl(EPServiceProvider epServiceProvider, EPServicesContext services) {
        this.services = services;
        this.epServiceProvider = (EPServiceProviderSPI) epServiceProvider;

        // lock for starting and stopping statements
        this.eventProcessingRWLock = services.getEventProcessingRWLock();

        this.stmtIdToDescMap = new HashMap<String, EPStatementDesc>();
        this.stmtNameToStmtMap = new HashMap<String, EPStatement>();
        this.stmtNameToIdMap = new LinkedHashMap<String, String>();

        observers = new CopyOnWriteArraySet<StatementLifecycleObserver>();
    }

    public void addObserver(StatementLifecycleObserver observer) {
        observers.add(observer);
    }

    public void removeObserver(StatementLifecycleObserver observer) {
        observers.remove(observer);
    }

    public void destroy() {
        this.destroyAllStatements();
    }

    public void init() {
        // called after services are activated, to begin statement loading from store
    }

    public synchronized EPStatement createAndStart(StatementSpecRaw statementSpec, String expression,
            boolean isPattern, String optStatementName, Object userObject,
            EPIsolationUnitServices isolationUnitServices, String statementId,
            EPStatementObjectModel optionalModel) {
        String assignedStatementId = statementId;
        if (assignedStatementId == null) {
            assignedStatementId = UuidGenerator.generate();
        }

        EPStatementDesc desc = createStoppedAssignName(statementSpec, expression, isPattern, optStatementName,
                assignedStatementId, null, userObject, isolationUnitServices, optionalModel);
        start(statementId, desc, true, false, false);
        return desc.getEpStatement();
    }

    /**
     * Creates and starts statement.
     * @param statementSpec defines the statement
     * @param expression is the EPL
     * @param isPattern is true for patterns
     * @param optStatementName is the optional statement name
     * @param statementId is the statement id
     * @param optAdditionalContext additional context for use by the statement context
     * @param userObject the application define user object associated to each statement, if supplied
     * @param isolationUnitServices isolated service services
     * @return started statement
     */
    protected synchronized EPStatementDesc createStoppedAssignName(StatementSpecRaw statementSpec,
            String expression, boolean isPattern, String optStatementName, String statementId,
            Map<String, Object> optAdditionalContext, Object userObject,
            EPIsolationUnitServices isolationUnitServices, EPStatementObjectModel optionalModel) {
        boolean nameProvided = false;
        String statementName = statementId;

        // find name annotation
        if (optStatementName == null) {
            if ((statementSpec.getAnnotations() != null) && (!statementSpec.getAnnotations().isEmpty())) {
                for (AnnotationDesc desc : statementSpec.getAnnotations()) {
                    if ((desc.getName().equals(Name.class.getSimpleName()))
                            || (desc.getName().equals(Name.class.getName()))) {
                        if (desc.getAttributes().get(0) != null) {
                            optStatementName = desc.getAttributes().get(0).getSecond().toString();
                        }
                    }
                }
            }
        }

        // Determine a statement name, i.e. use the id or use/generate one for the name passed in
        if (optStatementName != null) {
            statementName = getUniqueStatementName(optStatementName, statementId);
            nameProvided = true;
        }

        return createStopped(statementSpec, expression, isPattern, statementName, nameProvided, statementId,
                optAdditionalContext, userObject, isolationUnitServices, false, optionalModel);
    }

    /**
     * Create stopped statement.
     * @param statementSpec - statement definition
     * @param expression is the expression text
     * @param isPattern is true for patterns, false for non-patterns
     * @param statementName is the statement name assigned or given
     * @param statementId is the statement id
     * @param optAdditionalContext additional context for use by the statement context
     * @param userObject the application define user object associated to each statement, if supplied
     * @param isolationUnitServices isolated service services
     * @param isFailed to start the statement in failed state
     * @param nameProvided true when an explicit statement name is provided
     * @return stopped statement
     */
    protected synchronized EPStatementDesc createStopped(StatementSpecRaw statementSpec, String expression,
            boolean isPattern, String statementName, boolean nameProvided, String statementId,
            Map<String, Object> optAdditionalContext, Object userObject,
            EPIsolationUnitServices isolationUnitServices, boolean isFailed, EPStatementObjectModel optionalModel) {
        EPStatementDesc statementDesc;
        EPStatementStartMethod startMethod;

        Annotation[] annotations = AnnotationUtil.compileAnnotations(statementSpec.getAnnotations(),
                services.getEngineImportService(), expression);
        if (annotations != null) {
            for (Annotation annotation : annotations) {
                if (annotation instanceof Hint) {
                    statementSpec.setHasVariables(true);
                }
            }
        }

        String optionalCreateNamedWindowName = statementSpec.getCreateWindowDesc() != null
                ? statementSpec.getCreateWindowDesc().getWindowName()
                : null;
        StatementContext statementContext = services.getStatementContextFactory().makeContext(statementId,
                statementName, expression, statementSpec.isHasVariables(), services, optAdditionalContext,
                statementSpec.getOnTriggerDesc(), statementSpec.getCreateWindowDesc(), false, annotations,
                isolationUnitServices, optionalCreateNamedWindowName);
        StatementSpecCompiled compiledSpec;
        try {
            compiledSpec = compile(statementSpec, expression, statementContext, false, annotations);
        } catch (EPStatementException ex) {
            stmtNameToIdMap.remove(statementName); // Clean out the statement name as it's already assigned
            throw ex;
        }

        // For insert-into streams, create a lock taken out as soon as an event is inserted
        // Makes the processing between chained statements more predictable.
        if (statementSpec.getInsertIntoDesc() != null
                || statementSpec.getOnTriggerDesc() instanceof OnTriggerMergeDesc) {
            String insertIntoStreamName = null;
            if (statementSpec.getInsertIntoDesc() != null) {
                insertIntoStreamName = statementSpec.getInsertIntoDesc().getEventTypeName();
            } else {
                insertIntoStreamName = "merge";
            }
            String latchFactoryNameBack = "insert_stream_B_" + insertIntoStreamName + "_" + statementId;
            String latchFactoryNameFront = "insert_stream_F_" + insertIntoStreamName + "_" + statementId;
            long msecTimeout = services.getEngineSettingsService().getEngineSettings().getThreading()
                    .getInsertIntoDispatchTimeout();
            ConfigurationEngineDefaults.Threading.Locking locking = services.getEngineSettingsService()
                    .getEngineSettings().getThreading().getInsertIntoDispatchLocking();
            InsertIntoLatchFactory latchFactoryFront = new InsertIntoLatchFactory(latchFactoryNameFront,
                    msecTimeout, locking, services.getTimeSource());
            InsertIntoLatchFactory latchFactoryBack = new InsertIntoLatchFactory(latchFactoryNameBack, msecTimeout,
                    locking, services.getTimeSource());
            statementContext.getEpStatementHandle().setInsertIntoFrontLatchFactory(latchFactoryFront);
            statementContext.getEpStatementHandle().setInsertIntoBackLatchFactory(latchFactoryBack);
        }

        // In a join statements if the same event type or it's deep super types are used in the join more then once,
        // then this is a self-join and the statement handle must know to dispatch the results together
        boolean canSelfJoin = isPotentialSelfJoin(compiledSpec);
        statementContext.getEpStatementHandle().setCanSelfJoin(canSelfJoin);

        // add statically typed event type references: those in the from clause; Dynamic (created) types collected by statement context and added on start
        services.getStatementEventTypeRefService().addReferences(statementName,
                compiledSpec.getEventTypeReferences());

        // add variable references
        services.getStatementVariableRefService().addReferences(statementName,
                compiledSpec.getVariableReferences());

        // create metadata
        StatementMetadata statementMetadata = services.getStatementMetadataFactory()
                .create(new StatementMetadataFactoryContext(statementName, statementId, statementContext,
                        statementSpec, expression, isPattern, optionalModel));

        eventProcessingRWLock.acquireWriteLock();
        try {
            // create statement - may fail for parser and simple validation errors
            boolean preserveDispatchOrder = services.getEngineSettingsService().getEngineSettings().getThreading()
                    .isListenerDispatchPreserveOrder();
            boolean isSpinLocks = services.getEngineSettingsService().getEngineSettings().getThreading()
                    .getListenerDispatchLocking() == ConfigurationEngineDefaults.Threading.Locking.SPIN;
            long blockingTimeout = services.getEngineSettingsService().getEngineSettings().getThreading()
                    .getListenerDispatchTimeout();
            long timeLastStateChange = services.getSchedulingService().getTime();
            EPStatementSPI statement = new EPStatementImpl(statementId, statementName, expression,
                    statementSpec.getExpressionNoAnnotations(), isPattern, services.getDispatchService(), this,
                    timeLastStateChange, preserveDispatchOrder, isSpinLocks, blockingTimeout,
                    services.getTimeSource(), statementMetadata, userObject, compiledSpec.getAnnotations(),
                    statementContext, isFailed, nameProvided);

            boolean isInsertInto = statementSpec.getInsertIntoDesc() != null;
            boolean isDistinct = statementSpec.getSelectClauseSpec().isDistinct();
            boolean isForClause = statementSpec.getForClauseSpec() != null;
            statementContext.getStatementResultService().setContext(statement, epServiceProvider, isInsertInto,
                    isPattern, isDistinct, isForClause, statementContext.getEpStatementHandle().getMetricsHandle());

            // create start method
            startMethod = new EPStatementStartMethod(compiledSpec, services, statementContext);

            // keep track of the insert-into statements supplying streams.
            // these may need to lock to get more predictable behavior for multithreaded processing.
            String insertIntoStreamName = null;
            if (statementSpec.getInsertIntoDesc() != null) {
                insertIntoStreamName = statementSpec.getInsertIntoDesc().getEventTypeName();
            }

            statementDesc = new EPStatementDesc(statement, startMethod, null, null, insertIntoStreamName,
                    statementContext.getEpStatementHandle(), statementContext);
            stmtIdToDescMap.put(statementId, statementDesc);
            stmtNameToStmtMap.put(statementName, statement);
            stmtNameToIdMap.put(statementName, statementId);

            dispatchStatementLifecycleEvent(
                    new StatementLifecycleEvent(statement, StatementLifecycleEvent.LifecycleEventType.CREATE));
        } catch (RuntimeException ex) {
            stmtIdToDescMap.remove(statementId);
            stmtNameToIdMap.remove(statementName);
            stmtNameToStmtMap.remove(statementName);
            throw ex;
        } finally {
            eventProcessingRWLock.releaseWriteLock();
        }

        return statementDesc;
    }

    private boolean isPotentialSelfJoin(StatementSpecCompiled spec) {
        // if order-by is specified, ans since multiple output rows may produce, ensure dispatch
        if (!spec.getOrderByList().isEmpty()) {
            return true;
        }

        for (StreamSpecCompiled streamSpec : spec.getStreamSpecs()) {
            if (streamSpec instanceof PatternStreamSpecCompiled) {
                return true;
            }
        }

        // not a self join
        if ((spec.getStreamSpecs().size() <= 1) && (spec.getSubSelectExpressions().isEmpty())) {
            return false;
        }

        // join - determine types joined
        List<EventType> filteredTypes = new ArrayList<EventType>();

        // consider subqueryes
        Set<EventType> optSubselectTypes = populateSubqueryTypes(spec.getSubSelectExpressions());

        boolean hasFilterStream = false;
        for (StreamSpecCompiled streamSpec : spec.getStreamSpecs()) {
            if (streamSpec instanceof FilterStreamSpecCompiled) {
                EventType type = ((FilterStreamSpecCompiled) streamSpec).getFilterSpec().getFilterForEventType();
                filteredTypes.add(type);
                hasFilterStream = true;
            }
        }

        if ((filteredTypes.size() == 1) && (optSubselectTypes.isEmpty())) {
            return false;
        }

        // pattern-only streams are not self-joins
        if (!hasFilterStream) {
            return false;
        }

        // is type overlap in filters
        for (int i = 0; i < filteredTypes.size(); i++) {
            for (int j = i + 1; j < filteredTypes.size(); j++) {
                EventType typeOne = filteredTypes.get(i);
                EventType typeTwo = filteredTypes.get(j);
                if (typeOne == typeTwo) {
                    return true;
                }

                if (typeOne.getSuperTypes() != null) {
                    for (EventType typeOneSuper : typeOne.getSuperTypes()) {
                        if (typeOneSuper == typeTwo) {
                            return true;
                        }
                    }
                }
                if (typeTwo.getSuperTypes() != null) {
                    for (EventType typeTwoSuper : typeTwo.getSuperTypes()) {
                        if (typeOne == typeTwoSuper) {
                            return true;
                        }
                    }
                }
            }
        }

        // analyze subselect types
        if (!optSubselectTypes.isEmpty()) {
            for (int i = 0; i < filteredTypes.size(); i++) {
                EventType typeOne = filteredTypes.get(i);
                if (optSubselectTypes.contains(typeOne)) {
                    return true;
                }

                if (typeOne.getSuperTypes() != null) {
                    for (EventType typeOneSuper : typeOne.getSuperTypes()) {
                        if (optSubselectTypes.contains(typeOneSuper)) {
                            return true;
                        }
                    }
                }
            }
        }

        return false;
    }

    private Set<EventType> populateSubqueryTypes(List<ExprSubselectNode> subSelectExpressions) {
        Set<EventType> set = null;
        for (ExprSubselectNode subselect : subSelectExpressions) {
            for (StreamSpecCompiled streamSpec : subselect.getStatementSpecCompiled().getStreamSpecs()) {
                if (streamSpec instanceof FilterStreamSpecCompiled) {
                    EventType type = ((FilterStreamSpecCompiled) streamSpec).getFilterSpec()
                            .getFilterForEventType();
                    if (set == null) {
                        set = new HashSet<EventType>();
                    }
                    set.add(type);
                } else if (streamSpec instanceof PatternStreamSpecCompiled) {
                    EvalNodeAnalysisResult evalNodeAnalysisResult = EvalNodeUtil
                            .recursiveAnalyzeChildNodes(((PatternStreamSpecCompiled) streamSpec).getEvalNode());
                    List<EvalFilterNode> filterNodes = evalNodeAnalysisResult.getFilterNodes();
                    for (EvalFilterNode filterNode : filterNodes) {
                        if (set == null) {
                            set = new HashSet<EventType>();
                        }
                        set.add(filterNode.getFilterSpec().getFilterForEventType());
                    }
                }
            }
        }
        if (set == null) {
            return Collections.EMPTY_SET;
        }
        return set;
    }

    public synchronized void start(String statementId) {
        if (log.isDebugEnabled()) {
            log.debug(".start Starting statement " + statementId);
        }

        // Acquire a lock for event processing as threads may be in the views used by the statement
        // and that could conflict with the destroy of views
        eventProcessingRWLock.acquireWriteLock();
        try {
            EPStatementDesc desc = stmtIdToDescMap.get(statementId);
            if (desc == null) {
                throw new IllegalStateException("Cannot start statement, statement is in destroyed state");
            }
            startInternal(statementId, desc, false, false, false);
        } finally {
            eventProcessingRWLock.releaseWriteLock();
        }
    }

    /**
     * Start the given statement.
     * @param statementId is the statement id
     * @param desc is the cached statement info
     * @param isNewStatement indicator whether the statement is new or a stop-restart statement
     * @param isRecoveringStatement if the statement is recovering or new
     * @param isResilient true if recovering a resilient stmt
     */
    public void start(String statementId, EPStatementDesc desc, boolean isNewStatement,
            boolean isRecoveringStatement, boolean isResilient) {
        if (log.isDebugEnabled()) {
            log.debug(".start Starting statement " + statementId + " from desc=" + desc);
        }

        // Acquire a lock for event processing as threads may be in the views used by the statement
        // and that could conflict with the destroy of views
        eventProcessingRWLock.acquireWriteLock();
        try {
            startInternal(statementId, desc, isNewStatement, isRecoveringStatement, isResilient);
        } finally {
            eventProcessingRWLock.releaseWriteLock();
        }
    }

    private void startInternal(String statementId, EPStatementDesc desc, boolean isNewStatement,
            boolean isRecoveringStatement, boolean isResilient) {
        if (log.isDebugEnabled()) {
            log.debug(".startInternal Starting statement " + statementId + " from desc=" + desc);
        }

        if (desc.getStartMethod() == null) {
            throw new IllegalStateException("Statement start method not found for id " + statementId);
        }

        EPStatementSPI statement = desc.getEpStatement();
        if (statement.getState() == EPStatementState.STARTED) {
            log.debug(".startInternal - Statement already started");
            return;
        }

        EPStatementStartResult startResult;
        try {
            startResult = desc.getStartMethod().start(isNewStatement, isRecoveringStatement, isResilient);
        } catch (EPStatementException ex) {
            handleRemove(statementId, statement.getName());
            log.debug(".start Error starting statement", ex);
            throw ex;
        } catch (ExprValidationException ex) {
            handleRemove(statementId, statement.getName());
            log.debug(".start Error starting statement", ex);
            throw new EPStatementException("Error starting statement: " + ex.getMessage(), ex, statement.getText());
        } catch (ViewProcessingException ex) {
            handleRemove(statementId, statement.getName());
            log.debug(".start Error starting statement", ex);
            throw new EPStatementException("Error starting statement: " + ex.getMessage(), ex, statement.getText());
        } catch (RuntimeException ex) {
            stmtIdToDescMap.remove(statementId);
            stmtNameToIdMap.remove(statement.getName());
            stmtNameToStmtMap.remove(statement.getName());
            log.debug(".start Error starting statement", ex);
            throw new EPStatementException("Unexpected exception starting statement: " + ex.getMessage(), ex,
                    statement.getText());
        }

        // add statically typed event type references: those in the from clause; Dynamic (created) types collected by statement context and added on start
        services.getStatementEventTypeRefService().addReferences(desc.getEpStatement().getName(),
                desc.getStatementContext().getDynamicReferenceEventTypes());

        // hook up
        Viewable parentView = startResult.getViewable();
        desc.setStopMethod(startResult.getStopMethod());
        desc.setDestroyMethod(startResult.getDestroyMethod());
        statement.setParentView(parentView);
        long timeLastStateChange = services.getSchedulingService().getTime();
        statement.setCurrentState(EPStatementState.STARTED, timeLastStateChange);

        dispatchStatementLifecycleEvent(
                new StatementLifecycleEvent(statement, StatementLifecycleEvent.LifecycleEventType.STATECHANGE));
    }

    private void handleRemove(String statementId, String statementName) {
        stmtIdToDescMap.remove(statementId);
        stmtNameToIdMap.remove(statementName);
        stmtNameToStmtMap.remove(statementName);
        services.getStatementEventTypeRefService().removeReferencesStatement(statementName);
    }

    public synchronized void stop(String statementId) {
        // Acquire a lock for event processing as threads may be in the views used by the statement
        // and that could conflict with the destroy of views
        eventProcessingRWLock.acquireWriteLock();
        try {
            EPStatementDesc desc = stmtIdToDescMap.get(statementId);
            if (desc == null) {
                throw new IllegalStateException("Cannot stop statement, statement is in destroyed state");
            }

            EPStatementSPI statement = desc.getEpStatement();
            EPStatementStopMethod stopMethod = desc.getStopMethod();
            if (stopMethod == null) {
                throw new IllegalStateException("Stop method not found for statement " + statementId);
            }

            if (statement.getState() == EPStatementState.STOPPED) {
                log.debug(".startInternal - Statement already stopped");
                return;
            }

            stopMethod.stop();
            statement.setParentView(null);
            desc.setStopMethod(null);

            long timeLastStateChange = services.getSchedulingService().getTime();
            statement.setCurrentState(EPStatementState.STOPPED, timeLastStateChange);

            dispatchStatementLifecycleEvent(
                    new StatementLifecycleEvent(statement, StatementLifecycleEvent.LifecycleEventType.STATECHANGE));
        } finally {
            eventProcessingRWLock.releaseWriteLock();
        }
    }

    public synchronized void destroy(String statementId) {
        // Acquire a lock for event processing as threads may be in the views used by the statement
        // and that could conflict with the destroy of views
        eventProcessingRWLock.acquireWriteLock();
        try {
            EPStatementDesc desc = stmtIdToDescMap.get(statementId);
            if (desc == null) {
                log.debug(".startInternal - Statement already destroyed");
                return;
            }

            // remove referenced event types
            services.getStatementEventTypeRefService().removeReferencesStatement(desc.getEpStatement().getName());

            // remove referenced variabkes
            services.getStatementVariableRefService().removeReferencesStatement(desc.getEpStatement().getName());

            // remove the named window lock
            services.getNamedWindowService().removeNamedWindowLock(desc.getEpStatement().getName());

            EPStatementSPI statement = desc.getEpStatement();
            if (statement.getState() == EPStatementState.STARTED) {
                EPStatementStopMethod stopMethod = desc.getStopMethod();
                statement.setParentView(null);
                stopMethod.stop();
            }

            if (desc.getDestroyMethod() != null) {
                desc.getDestroyMethod().destroy();
            }

            long timeLastStateChange = services.getSchedulingService().getTime();
            statement.setCurrentState(EPStatementState.DESTROYED, timeLastStateChange);

            stmtNameToStmtMap.remove(statement.getName());
            stmtNameToIdMap.remove(statement.getName());
            stmtIdToDescMap.remove(statementId);

            dispatchStatementLifecycleEvent(
                    new StatementLifecycleEvent(statement, StatementLifecycleEvent.LifecycleEventType.STATECHANGE));
        } finally {
            eventProcessingRWLock.releaseWriteLock();
        }
    }

    public synchronized EPStatement getStatementByName(String name) {
        return stmtNameToStmtMap.get(name);
    }

    /**
     * Returns the statement given a statement id.
     * @param id is the statement id
     * @return statement
     */
    public EPStatementSPI getStatementById(String id) {
        EPStatementDesc statementDesc = this.stmtIdToDescMap.get(id);
        if (statementDesc == null) {
            log.warn("Could not locate statement descriptor for statement id '" + id + "'");
            return null;
        }
        return statementDesc.getEpStatement();
    }

    public synchronized String[] getStatementNames() {
        String[] statements = new String[stmtNameToStmtMap.size()];
        int count = 0;
        for (String key : stmtNameToStmtMap.keySet()) {
            statements[count++] = key;
        }
        return statements;
    }

    public synchronized void startAllStatements() throws EPException {
        String[] statementIds = getStatementIds();
        for (int i = 0; i < statementIds.length; i++) {
            EPStatement statement = stmtIdToDescMap.get(statementIds[i]).getEpStatement();
            if (statement.getState() == EPStatementState.STOPPED) {
                start(statementIds[i]);
            }
        }
    }

    public synchronized void stopAllStatements() throws EPException {
        String[] statementIds = getStatementIds();
        for (int i = 0; i < statementIds.length; i++) {
            EPStatement statement = stmtIdToDescMap.get(statementIds[i]).getEpStatement();
            if (statement.getState() == EPStatementState.STARTED) {
                stop(statementIds[i]);
            }
        }
    }

    public synchronized void destroyAllStatements() throws EPException {
        String[] statementIds = getStatementIds();
        for (int i = 0; i < statementIds.length; i++) {
            try {
                destroy(statementIds[i]);
            } catch (Exception ex) {
                log.warn("Error destroying statement:" + ex.getMessage());
            }
        }
    }

    private String[] getStatementIds() {
        String[] statementIds = new String[stmtNameToIdMap.size()];
        int count = 0;
        for (String id : stmtNameToIdMap.values()) {
            statementIds[count++] = id;
        }
        return statementIds;
    }

    private String getUniqueStatementName(String statementName, String statementId) {
        String finalStatementName;

        if (stmtNameToIdMap.containsKey(statementName)) {
            int count = 0;
            while (true) {
                finalStatementName = statementName + "--" + count;
                if (!(stmtNameToIdMap.containsKey(finalStatementName))) {
                    break;
                }
                if (count > Integer.MAX_VALUE - 2) {
                    throw new EPException("Failed to establish a unique statement name");
                }
                count++;
            }
        } else {
            finalStatementName = statementName;
        }

        stmtNameToIdMap.put(finalStatementName, statementId);
        return finalStatementName;
    }

    @Override
    public String getStatementNameById(String id) {
        EPStatementDesc desc = stmtIdToDescMap.get(id);
        if (desc != null) {
            return desc.getEpStatement().getName();
        }
        return null;
    }

    public void updatedListeners(EPStatement statement, EPStatementListenerSet listeners) {
        log.debug(".updatedListeners No action for base implementation");
    }

    /**
     * Compiles a statement returning the compile (verified, non-serializable) form of a statement.
     * @param spec is the statement specification
     * @param eplStatement the statement to compile
     * @param statementContext the statement services
     * @param isSubquery is true for subquery compilation or false for statement compile
     * @param annotations statement annotations
     * @return compiled statement
     * @throws EPStatementException if the statement cannot be compiled
     */
    protected static StatementSpecCompiled compile(StatementSpecRaw spec, String eplStatement,
            StatementContext statementContext, boolean isSubquery, Annotation[] annotations)
            throws EPStatementException {
        List<StreamSpecCompiled> compiledStreams;
        Set<String> eventTypeReferences = new HashSet<String>();

        // If not using a join and not specifying a data window, make the where-clause, if present, the filter of the stream
        // if selecting using filter spec, and not subquery in where clause
        if ((spec.getStreamSpecs().size() == 1) && (spec.getStreamSpecs().get(0) instanceof FilterStreamSpecRaw)
                && (spec.getStreamSpecs().get(0).getViewSpecs().isEmpty()) && (spec.getFilterRootNode() != null)
                && (spec.getOnTriggerDesc() == null) && (!isSubquery)) {
            boolean disqualified;
            ExprNode whereClause = spec.getFilterRootNode();

            ExprNodeSubselectVisitor visitor = new ExprNodeSubselectVisitor();
            whereClause.accept(visitor);
            disqualified = visitor.getSubselects().size() > 0;

            if (!disqualified) {
                ExprNodeViewResourceVisitor viewResourceVisitor = new ExprNodeViewResourceVisitor();
                whereClause.accept(viewResourceVisitor);
                disqualified = viewResourceVisitor.getExprNodes().size() > 0;
            }

            if (!disqualified) {
                // If an alias is provided, find all properties to ensure the alias gets removed
                String alias = spec.getStreamSpecs().get(0).getOptionalStreamName();
                if (alias != null) {
                    ExprNodeIdentifierCollectVisitor v = new ExprNodeIdentifierCollectVisitor();
                    whereClause.accept(v);
                    for (ExprIdentNode node : v.getExprProperties()) {
                        if (node.getStreamOrPropertyName() != null
                                && (node.getStreamOrPropertyName().equals(alias))) {
                            node.setStreamOrPropertyName(null);
                        }
                    }
                }

                spec.setFilterRootNode(null);
                FilterStreamSpecRaw streamSpec = (FilterStreamSpecRaw) spec.getStreamSpecs().get(0);
                streamSpec.getRawFilterSpec().getFilterExpressions().add(whereClause);
            }
        }

        // compile select-clause
        List<SelectClauseElementCompiled> selectElements = new ArrayList<SelectClauseElementCompiled>();
        SelectClauseSpecCompiled selectClauseCompiled = new SelectClauseSpecCompiled(selectElements,
                spec.getSelectClauseSpec().isDistinct());
        for (SelectClauseElementRaw raw : spec.getSelectClauseSpec().getSelectExprList()) {
            if (raw instanceof SelectClauseExprRawSpec) {
                SelectClauseExprRawSpec rawExpr = (SelectClauseExprRawSpec) raw;
                selectElements.add(new SelectClauseExprCompiledSpec(rawExpr.getSelectExpression(),
                        rawExpr.getOptionalAsName(), rawExpr.getOptionalAsName()));
            } else if (raw instanceof SelectClauseStreamRawSpec) {
                SelectClauseStreamRawSpec rawExpr = (SelectClauseStreamRawSpec) raw;
                selectElements.add(
                        new SelectClauseStreamCompiledSpec(rawExpr.getStreamName(), rawExpr.getOptionalAsName()));
            } else if (raw instanceof SelectClauseElementWildcard) {
                SelectClauseElementWildcard wildcard = (SelectClauseElementWildcard) raw;
                selectElements.add(wildcard);
            } else {
                throw new IllegalStateException(
                        "Unexpected select clause element class : " + raw.getClass().getName());
            }
        }

        // Determine Subselects for compilation, and lambda-expression shortcut syntax for named windows
        ExprNodeSubselectVisitor visitor;
        try {
            visitor = StatementLifecycleSvcUtil.walkSubselectAndDeclaredDotExpr(spec);
        } catch (ExprValidationException ex) {
            throw new EPStatementException(ex.getMessage(), eplStatement);
        }
        List<ExprSubselectNode> subselects = visitor.getSubselects();
        if (!visitor.getChainedExpressionsDot().isEmpty()) {
            rewriteNamedWindowSubselect(visitor.getChainedExpressionsDot(), subselects,
                    statementContext.getNamedWindowService());
        }

        // Compile subselects found
        int subselectNumber = 0;
        for (ExprSubselectNode subselect : subselects) {
            StatementSpecRaw raw = subselect.getStatementSpecRaw();
            StatementSpecCompiled compiled = compile(raw, eplStatement, statementContext, true, new Annotation[0]);
            subselectNumber++;
            subselect.setStatementSpecCompiled(compiled, subselectNumber);
        }

        // compile each stream used
        try {
            compiledStreams = new ArrayList<StreamSpecCompiled>();
            int streamNum = 0;
            for (StreamSpecRaw rawSpec : spec.getStreamSpecs()) {
                streamNum++;
                StreamSpecCompiled compiled = rawSpec.compile(statementContext, eventTypeReferences,
                        spec.getInsertIntoDesc() != null, Collections.singleton(streamNum));
                compiledStreams.add(compiled);
            }
        } catch (ExprValidationException ex) {
            log.info("Failed to compile statement: " + ex.getMessage(), ex);
            if (ex.getMessage() == null) {
                throw new EPStatementException(
                        "Unexpected exception compiling statement, please consult the log file and report the exception",
                        eplStatement);
            } else {
                throw new EPStatementException(ex.getMessage(), eplStatement);
            }
        } catch (RuntimeException ex) {
            String text = "Unexpected error compiling statement";
            log.error(text, ex);
            throw new EPStatementException(text + ": " + ex.getClass().getName() + ":" + ex.getMessage(),
                    eplStatement);
        }

        // for create window statements, we switch the filter to a new event type
        if (spec.getCreateWindowDesc() != null) {
            try {
                StreamSpecCompiled createWindowTypeSpec = compiledStreams.get(0);
                EventType selectFromType;
                String selectFromTypeName;
                if (createWindowTypeSpec instanceof FilterStreamSpecCompiled) {
                    FilterStreamSpecCompiled filterStreamSpec = (FilterStreamSpecCompiled) createWindowTypeSpec;
                    selectFromType = filterStreamSpec.getFilterSpec().getFilterForEventType();
                    selectFromTypeName = filterStreamSpec.getFilterSpec().getFilterForEventTypeName();

                    if (spec.getCreateWindowDesc().getInsertFilter() != null) {
                        throw new EPStatementException("A named window by name '" + selectFromTypeName
                                + "' could not be located, use the insert-keyword with an existing named window",
                                eplStatement);
                    }
                } else {
                    NamedWindowConsumerStreamSpec consumerStreamSpec = (NamedWindowConsumerStreamSpec) createWindowTypeSpec;
                    selectFromType = statementContext.getEventAdapterService()
                            .getExistsTypeByName(consumerStreamSpec.getWindowName());
                    selectFromTypeName = consumerStreamSpec.getWindowName();

                    if (spec.getCreateWindowDesc().getInsertFilter() != null) {
                        ExprNode insertIntoFilter = spec.getCreateWindowDesc().getInsertFilter();
                        String checkMinimal = ExprNodeUtility.isMinimalExpression(insertIntoFilter);
                        if (checkMinimal != null) {
                            throw new ExprValidationException(
                                    "Create window where-clause may not have " + checkMinimal);
                        }
                        StreamTypeService streamTypeService = new StreamTypeServiceImpl(selectFromType,
                                selectFromTypeName, true, statementContext.getEngineURI());
                        ExprValidationContext validationContext = new ExprValidationContext(streamTypeService,
                                statementContext.getMethodResolutionService(), null,
                                statementContext.getSchedulingService(), statementContext.getVariableService(),
                                statementContext, statementContext.getEventAdapterService(),
                                statementContext.getStatementName(), statementContext.getStatementId(),
                                statementContext.getAnnotations());
                        ExprNode insertFilter = ExprNodeUtility.getValidatedSubtree(
                                spec.getCreateWindowDesc().getInsertFilter(), validationContext);
                        spec.getCreateWindowDesc().setInsertFilter(insertFilter);
                    }

                    // set the window to insert from
                    spec.getCreateWindowDesc().setInsertFromWindow(consumerStreamSpec.getWindowName());
                }
                Pair<FilterSpecCompiled, SelectClauseSpecRaw> newFilter = handleCreateWindow(selectFromType,
                        selectFromTypeName, spec.getCreateWindowDesc().getColumns(), spec, eplStatement,
                        statementContext);
                eventTypeReferences.add(((EventTypeSPI) newFilter.getFirst().getFilterForEventType()).getMetadata()
                        .getPrimaryName());

                // view must be non-empty list
                if (spec.getCreateWindowDesc().getViewSpecs().isEmpty()) {
                    throw new ExprValidationException(NamedWindowService.ERROR_MSG_DATAWINDOWS);
                }

                // use the filter specification of the newly created event type and the views for the named window
                compiledStreams.clear();
                List<ViewSpec> views = new ArrayList<ViewSpec>(spec.getCreateWindowDesc().getViewSpecs());
                compiledStreams.add(new FilterStreamSpecCompiled(newFilter.getFirst(), views, null,
                        spec.getCreateWindowDesc().getStreamSpecOptions()));
                spec.setSelectClauseSpec(newFilter.getSecond());
            } catch (ExprValidationException e) {
                throw new EPStatementException(e.getMessage(), eplStatement);
            }
        }

        return new StatementSpecCompiled(spec.getOnTriggerDesc(), spec.getCreateWindowDesc(),
                spec.getCreateIndexDesc(), spec.getCreateVariableDesc(), spec.getCreateSchemaDesc(),
                spec.getInsertIntoDesc(), spec.getSelectStreamSelectorEnum(), selectClauseCompiled, compiledStreams,
                spec.getOuterJoinDescList(), spec.getFilterRootNode(), spec.getGroupByExpressions(),
                spec.getHavingExprRootNode(), spec.getOutputLimitSpec(), spec.getOrderByList(),
                visitor.getSubselects(), visitor.getDeclaredExpressions(), spec.getReferencedVariables(),
                spec.getRowLimitSpec(), eventTypeReferences, annotations, spec.getUpdateDesc(),
                spec.getMatchRecognizeSpec(), spec.getForClauseSpec(), spec.getSqlParameters());
    }

    private static void rewriteNamedWindowSubselect(List<ExprDotNode> chainedExpressionsDot,
            List<ExprSubselectNode> subselects, NamedWindowService service) {
        for (ExprDotNode dotNode : chainedExpressionsDot) {
            String proposedWindow = dotNode.getChainSpec().get(0).getName();
            if (!service.isNamedWindow(proposedWindow)) {
                continue;
            }

            // build spec for subselect
            StatementSpecRaw raw = new StatementSpecRaw(SelectClauseStreamSelectorEnum.ISTREAM_ONLY);
            FilterSpecRaw filter = new FilterSpecRaw(proposedWindow, Collections.<ExprNode>emptyList(), null);
            raw.getStreamSpecs().add(new FilterStreamSpecRaw(filter, Collections.<ViewSpec>emptyList(),
                    proposedWindow, new StreamSpecOptions()));

            ExprChainedSpec firstChain = dotNode.getChainSpec().remove(0);
            if (!firstChain.getParameters().isEmpty()) {
                if (firstChain.getParameters().size() == 1) {
                    raw.setFilterExprRootNode(firstChain.getParameters().get(0));
                } else {
                    ExprAndNode andNode = new ExprAndNodeImpl();
                    for (ExprNode node : firstChain.getParameters()) {
                        andNode.addChildNode(node);
                    }
                    raw.setFilterExprRootNode(andNode);
                }
            }

            // activate subselect
            ExprSubselectNode subselect = new ExprSubselectRowNode(raw);
            subselects.add(subselect);
            dotNode.getChildNodes().clear();
            dotNode.addChildNode(subselect);
        }
    }

    /**
     * Compile a select clause allowing subselects.
     * @param spec to compile
     * @return select clause compiled
     * @throws ExprValidationException when validation fails
     */
    public static SelectClauseSpecCompiled compileSelectAllowSubselect(SelectClauseSpecRaw spec)
            throws ExprValidationException {
        // Look for expressions with sub-selects in select expression list and filter expression
        // Recursively compile the statement within the statement.
        ExprNodeSubselectVisitor visitor = new ExprNodeSubselectVisitor();
        List<SelectClauseElementCompiled> selectElements = new ArrayList<SelectClauseElementCompiled>();
        SelectClauseSpecCompiled selectClauseCompiled = new SelectClauseSpecCompiled(selectElements,
                spec.isDistinct());
        for (SelectClauseElementRaw raw : spec.getSelectExprList()) {
            if (raw instanceof SelectClauseExprRawSpec) {
                SelectClauseExprRawSpec rawExpr = (SelectClauseExprRawSpec) raw;
                rawExpr.getSelectExpression().accept(visitor);
                selectElements.add(new SelectClauseExprCompiledSpec(rawExpr.getSelectExpression(),
                        rawExpr.getOptionalAsName(), rawExpr.getOptionalAsName()));
            } else if (raw instanceof SelectClauseStreamRawSpec) {
                SelectClauseStreamRawSpec rawExpr = (SelectClauseStreamRawSpec) raw;
                selectElements.add(
                        new SelectClauseStreamCompiledSpec(rawExpr.getStreamName(), rawExpr.getOptionalAsName()));
            } else if (raw instanceof SelectClauseElementWildcard) {
                SelectClauseElementWildcard wildcard = (SelectClauseElementWildcard) raw;
                selectElements.add(wildcard);
            } else {
                throw new IllegalStateException(
                        "Unexpected select clause element class : " + raw.getClass().getName());
            }
        }
        return selectClauseCompiled;
    }

    // The create window command:
    //      create window windowName[.window_view_list] as [select properties from] type
    //
    // This section expected s single FilterStreamSpecCompiled representing the selected type.
    // It creates a new event type representing the window type and a sets the type selected on the filter stream spec.
    private static Pair<FilterSpecCompiled, SelectClauseSpecRaw> handleCreateWindow(EventType selectFromType,
            String selectFromTypeName, List<ColumnDesc> columns, StatementSpecRaw spec, String eplStatement,
            StatementContext statementContext) throws ExprValidationException {
        String typeName = spec.getCreateWindowDesc().getWindowName();
        EventType targetType;

        // Validate the select expressions which consists of properties only
        List<NamedWindowSelectedProps> select = compileLimitedSelect(spec.getSelectClauseSpec(), eplStatement,
                selectFromType, selectFromTypeName, statementContext.getEngineURI(), statementContext,
                statementContext.getMethodResolutionService(), statementContext.getEventAdapterService(),
                statementContext.getStatementName(), statementContext.getStatementId(),
                statementContext.getAnnotations());

        // Create Map or Wrapper event type from the select clause of the window.
        // If no columns selected, simply create a wrapper type
        // Build a list of properties
        SelectClauseSpecRaw newSelectClauseSpecRaw = new SelectClauseSpecRaw();
        Map<String, Object> properties;
        boolean hasProperties = false;
        if ((columns != null) && (!columns.isEmpty())) {
            properties = TypeBuilderUtil.buildType(columns);
            hasProperties = true;
        } else {
            properties = new HashMap<String, Object>();
            for (NamedWindowSelectedProps selectElement : select) {
                if (selectElement.getFragmentType() != null) {
                    properties.put(selectElement.getAssignedName(), selectElement.getFragmentType());
                } else {
                    properties.put(selectElement.getAssignedName(), selectElement.getSelectExpressionType());
                }

                // Add any properties to the new select clause for use by consumers to the statement itself
                newSelectClauseSpecRaw.add(
                        new SelectClauseExprRawSpec(new ExprIdentNodeImpl(selectElement.getAssignedName()), null));
                hasProperties = true;
            }
        }

        // Create Map or Wrapper event type from the select clause of the window.
        // If no columns selected, simply create a wrapper type
        boolean isOnlyWildcard = spec.getSelectClauseSpec().isOnlyWildcard();
        boolean isWildcard = spec.getSelectClauseSpec().isUsingWildcard();
        if (statementContext.getValueAddEventService().isRevisionTypeName(selectFromTypeName)) {
            targetType = statementContext.getValueAddEventService().createRevisionType(typeName, selectFromTypeName,
                    statementContext.getStatementStopService(), statementContext.getEventAdapterService(),
                    statementContext.getEventTypeIdGenerator());
        } else if (isWildcard && !isOnlyWildcard) {
            targetType = statementContext.getEventAdapterService().addWrapperType(typeName, selectFromType,
                    properties, true, false);
        } else {
            // Some columns selected, use the types of the columns
            if (hasProperties && !isOnlyWildcard) {
                targetType = statementContext.getEventAdapterService().addNestableMapType(typeName, properties,
                        null, false, false, false, true, false);
            } else {
                // No columns selected, no wildcard, use the type as is or as a wrapped type
                if (selectFromType instanceof MapEventType) {
                    MapEventType mapType = (MapEventType) selectFromType;
                    targetType = statementContext.getEventAdapterService().addNestableMapType(typeName,
                            mapType.getTypes(), null, false, false, false, true, false);
                } else {
                    Map<String, Object> addOnTypes = new HashMap<String, Object>();
                    targetType = statementContext.getEventAdapterService().addWrapperType(typeName, selectFromType,
                            addOnTypes, true, false);
                }
            }
        }

        FilterSpecCompiled filter = new FilterSpecCompiled(targetType, typeName, new ArrayList<FilterSpecParam>(),
                null);
        return new Pair<FilterSpecCompiled, SelectClauseSpecRaw>(filter, newSelectClauseSpecRaw);
    }

    private static List<NamedWindowSelectedProps> compileLimitedSelect(SelectClauseSpecRaw spec,
            String eplStatement, EventType singleType, String selectFromTypeName, String engineURI,
            ExprEvaluatorContext exprEvaluatorContext, MethodResolutionService methodResolutionService,
            EventAdapterService eventAdapterService, String statementName, String statementId,
            Annotation[] annotations) {
        List<NamedWindowSelectedProps> selectProps = new LinkedList<NamedWindowSelectedProps>();
        StreamTypeService streams = new StreamTypeServiceImpl(new EventType[] { singleType },
                new String[] { "stream_0" }, new boolean[] { false }, engineURI, false);

        ExprValidationContext validationContext = new ExprValidationContext(streams, methodResolutionService, null,
                null, null, exprEvaluatorContext, eventAdapterService, statementName, statementId, annotations);
        for (SelectClauseElementRaw raw : spec.getSelectExprList()) {
            if (!(raw instanceof SelectClauseExprRawSpec)) {
                continue;
            }
            SelectClauseExprRawSpec exprSpec = (SelectClauseExprRawSpec) raw;
            ExprNode validatedExpression;
            try {
                validatedExpression = ExprNodeUtility.getValidatedSubtree(exprSpec.getSelectExpression(),
                        validationContext);
            } catch (ExprValidationException e) {
                throw new EPStatementException(e.getMessage(), eplStatement);
            }

            // determine an element name if none assigned
            String asName = exprSpec.getOptionalAsName();
            if (asName == null) {
                asName = validatedExpression.toExpressionString();
            }

            // check for fragments
            EventType fragmentType = null;
            if ((validatedExpression instanceof ExprIdentNode) && (!(singleType instanceof NativeEventType))) {
                ExprIdentNode identNode = (ExprIdentNode) validatedExpression;
                FragmentEventType fragmentEventType = singleType.getFragmentType(identNode.getFullUnresolvedName());
                if ((fragmentEventType != null) && (!fragmentEventType.isNative())) {
                    fragmentType = fragmentEventType.getFragmentType();
                }
            }

            NamedWindowSelectedProps validatedElement = new NamedWindowSelectedProps(
                    validatedExpression.getExprEvaluator().getType(), asName, fragmentType);
            selectProps.add(validatedElement);
        }

        return selectProps;
    }

    public void dispatchStatementLifecycleEvent(StatementLifecycleEvent event) {
        for (StatementLifecycleObserver observer : observers) {
            observer.observe(event);
        }
    }

    /**
     * Statement information.
     */
    public static class EPStatementDesc {
        private EPStatementSPI epStatement;
        private EPStatementStartMethod startMethod;
        private EPStatementStopMethod stopMethod;
        private EPStatementDestroyMethod destroyMethod;
        private String optInsertIntoStream;
        private EPStatementHandle statementHandle;
        private StatementContext statementContext;

        /**
         * Ctor.
         * @param epStatement the statement
         * @param startMethod the start method
         * @param stopMethod the stop method
         * @param optInsertIntoStream is the insert-into stream name, or null if not using insert-into
         * @param statementHandle is the locking handle for the statement
         * @param statementContext statement context
         * @param destroyMethod method to call when destroyed
         */
        public EPStatementDesc(EPStatementSPI epStatement, EPStatementStartMethod startMethod,
                EPStatementStopMethod stopMethod, EPStatementDestroyMethod destroyMethod,
                String optInsertIntoStream, EPStatementHandle statementHandle, StatementContext statementContext) {
            this.epStatement = epStatement;
            this.startMethod = startMethod;
            this.stopMethod = stopMethod;
            this.destroyMethod = destroyMethod;
            this.optInsertIntoStream = optInsertIntoStream;
            this.statementHandle = statementHandle;
            this.statementContext = statementContext;
        }

        /**
         * Returns the statement.
         * @return statement.
         */
        public EPStatementSPI getEpStatement() {
            return epStatement;
        }

        /**
         * Returns the start method.
         * @return start method
         */
        public EPStatementStartMethod getStartMethod() {
            return startMethod;
        }

        /**
         * Returns the stop method.
         * @return stop method
         */
        public EPStatementStopMethod getStopMethod() {
            return stopMethod;
        }

        /**
         * Return the insert-into stream name, or null if no insert-into
         * @return stream name
         */
        public String getOptInsertIntoStream() {
            return optInsertIntoStream;
        }

        /**
         * Sets the stop method.
         * @param stopMethod to set
         */
        public void setStopMethod(EPStatementStopMethod stopMethod) {
            this.stopMethod = stopMethod;
        }

        /**
         * Returns the statements handle.
         * @return statement handle
         */
        public EPStatementHandle getStatementHandle() {
            return statementHandle;
        }

        /**
         * Returns the statement context.
         * @return statement context
         */
        public StatementContext getStatementContext() {
            return statementContext;
        }

        /**
         * Set method to call when destroyed.
         * @param destroyMethod method
         */
        public void setDestroyMethod(EPStatementDestroyMethod destroyMethod) {
            this.destroyMethod = destroyMethod;
        }

        /**
         * Return destroy method.
         * @return method.
         */
        public EPStatementDestroyMethod getDestroyMethod() {
            return destroyMethod;
        }
    }
}