Java tutorial
/************************************************************************************** * 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.schedule; import com.espertech.esper.client.util.DateTime; import com.espertech.esper.metrics.jmx.JmxGetter; import com.espertech.esper.timer.TimeSourceService; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.util.*; /** * Implements the schedule service by simply keeping a sorted set of long millisecond * values and a set of handles for each. * <p> * Synchronized since statement creation and event evaluation by multiple (event send) threads * can lead to callbacks added/removed asynchronously. */ public final class SchedulingServiceImpl implements SchedulingServiceSPI { // Map of time and handle private final SortedMap<Long, SortedMap<ScheduleSlot, ScheduleHandle>> timeHandleMap; // Map of handle and handle list for faster removal private final Map<ScheduleHandle, SortedMap<ScheduleSlot, ScheduleHandle>> handleSetMap; // Current time - used for evaluation as well as for adding new handles private volatile long currentTime; /** * Constructor. * @param timeSourceService time source provider */ public SchedulingServiceImpl(TimeSourceService timeSourceService) { this.timeHandleMap = new TreeMap<Long, SortedMap<ScheduleSlot, ScheduleHandle>>(); this.handleSetMap = new HashMap<ScheduleHandle, SortedMap<ScheduleSlot, ScheduleHandle>>(); // initialize time to just before now as there is a check for duplicate external time events this.currentTime = timeSourceService.getTimeMillis() - 1; } public void destroy() { log.debug("Destroying scheduling service"); handleSetMap.clear(); timeHandleMap.clear(); } public long getTime() { // note that this.currentTime is volatile return this.currentTime; } public synchronized final void setTime(long currentTime) { this.currentTime = currentTime; } public synchronized final void add(long afterMSec, ScheduleHandle handle, ScheduleSlot slot) throws ScheduleServiceException { if (handleSetMap.containsKey(handle)) { remove(handle, slot); } long triggerOnTime = currentTime + afterMSec; addTrigger(slot, handle, triggerOnTime); } public synchronized final void remove(ScheduleHandle handle, ScheduleSlot slot) { SortedMap<ScheduleSlot, ScheduleHandle> handleSet = handleSetMap.get(handle); if (handleSet == null) { // If it already has been removed then that's fine; // Such could be the case when 2 timers fireStatementStopped at the same time, and one stops the other return; } handleSet.remove(slot); handleSetMap.remove(handle); } public synchronized final void evaluate(Collection<ScheduleHandle> handles) { // Get the values on or before the current time - to get those that are exactly on the // current time we just add one to the current time for getting the head map SortedMap<Long, SortedMap<ScheduleSlot, ScheduleHandle>> headMap = timeHandleMap.headMap(currentTime + 1); if (headMap.isEmpty()) { return; } // First determine all triggers to shoot List<Long> removeKeys = new ArrayList<Long>(); for (Map.Entry<Long, SortedMap<ScheduleSlot, ScheduleHandle>> entry : headMap.entrySet()) { Long key = entry.getKey(); SortedMap<ScheduleSlot, ScheduleHandle> value = entry.getValue(); removeKeys.add(key); for (ScheduleHandle handle : value.values()) { handles.add(handle); } } // Next remove all handles for (Map.Entry<Long, SortedMap<ScheduleSlot, ScheduleHandle>> entry : headMap.entrySet()) { for (ScheduleHandle handle : entry.getValue().values()) { handleSetMap.remove(handle); } } // Remove all triggered msec values for (Long key : removeKeys) { timeHandleMap.remove(key); } } public ScheduleSet take(Set<String> statementIds) { List<ScheduleSetEntry> list = new ArrayList<ScheduleSetEntry>(); long currentTime = getTime(); for (Map.Entry<Long, SortedMap<ScheduleSlot, ScheduleHandle>> schedule : timeHandleMap.entrySet()) { for (Map.Entry<ScheduleSlot, ScheduleHandle> entry : schedule.getValue().entrySet()) { if (statementIds.contains(entry.getValue().getStatementId())) { long relative = schedule.getKey() - currentTime; list.add(new ScheduleSetEntry(relative, entry.getKey(), entry.getValue())); } } } for (ScheduleSetEntry entry : list) { remove(entry.getHandle(), entry.getSlot()); } return new ScheduleSet(list); } public void apply(ScheduleSet scheduleSet) { for (ScheduleSetEntry entry : scheduleSet.getList()) { add(entry.getTime(), entry.getHandle(), entry.getSlot()); } } private void addTrigger(ScheduleSlot slot, ScheduleHandle handle, long triggerTime) { SortedMap<ScheduleSlot, ScheduleHandle> handleSet = timeHandleMap.get(triggerTime); if (handleSet == null) { handleSet = new TreeMap<ScheduleSlot, ScheduleHandle>(); timeHandleMap.put(triggerTime, handleSet); } handleSet.put(slot, handle); handleSetMap.put(handle, handleSet); } @JmxGetter(name = "TimeHandleCount", description = "Number of outstanding time evaluations") public int getTimeHandleCount() { return timeHandleMap.size(); } @JmxGetter(name = "FurthestTimeHandle", description = "Furthest outstanding time evaluation") public String getFurthestTimeHandleDate() { Long handle = getFurthestTimeHandle(); if (handle != null) { return DateTime.print(handle); } return null; } @JmxGetter(name = "NearestTimeHandle", description = "Nearest outstanding time evaluation") public String getNearestTimeHandleDate() { Long handle = getNearestTimeHandle(); if (handle != null) { return DateTime.print(handle); } return null; } public Long getFurthestTimeHandle() { if (!timeHandleMap.isEmpty()) { return timeHandleMap.lastKey(); } return null; } public int getScheduleHandleCount() { return handleSetMap.size(); } public boolean isScheduled(ScheduleHandle handle) { return handleSetMap.containsKey(handle); } @Override public synchronized Long getNearestTimeHandle() { if (timeHandleMap.isEmpty()) { return null; } for (Map.Entry<Long, SortedMap<ScheduleSlot, ScheduleHandle>> entry : timeHandleMap.entrySet()) { if (entry.getValue().isEmpty()) { continue; } return entry.getKey(); } return null; } public void visitSchedules(ScheduleVisitor visitor) { ScheduleVisit visit = new ScheduleVisit(); for (Map.Entry<Long, SortedMap<ScheduleSlot, ScheduleHandle>> entry : timeHandleMap.entrySet()) { visit.setTimestamp(entry.getKey()); for (Map.Entry<ScheduleSlot, ScheduleHandle> inner : entry.getValue().entrySet()) { visit.setStatementId(inner.getValue().getStatementId()); visit.setAgentInstanceId(inner.getValue().getAgentInstanceId()); visitor.visit(visit); } } } private static final Log log = LogFactory.getLog(SchedulingServiceImpl.class); }