Java tutorial
/* Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.raise.orgs.impl; import java.io.Serializable; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.commons.lang3.ObjectUtils; import org.apache.commons.lang3.StringUtils; import com.raise.orgs.ActivitiException; import com.raise.orgs.impl.context.Context; import com.raise.orgs.impl.interceptor.Command; import com.raise.orgs.impl.interceptor.CommandContext; import com.raise.orgs.impl.interceptor.CommandExecutor; import com.raise.orgs.query.NativeQuery; /** * Abstract superclass for all native query types. * * @author Bernd Ruecker (camunda) */ public abstract class AbstractNativeQuery<T extends NativeQuery<?, ?>, U> implements Command<Object>, NativeQuery<T, U>, Serializable { private static final long serialVersionUID = 1L; private static enum ResultType { LIST, LIST_PAGE, SINGLE_RESULT, COUNT } protected transient CommandExecutor commandExecutor; protected transient CommandContext commandContext; protected int maxResults = Integer.MAX_VALUE; protected int firstResult = 0; protected ResultType resultType; private Map<String, Object> parameters = new HashMap<String, Object>(); private String sqlStatement; protected AbstractNativeQuery(CommandExecutor commandExecutor) { this.commandExecutor = commandExecutor; } public AbstractNativeQuery(CommandContext commandContext) { this.commandContext = commandContext; } public AbstractNativeQuery<T, U> setCommandExecutor(CommandExecutor commandExecutor) { this.commandExecutor = commandExecutor; return this; } @SuppressWarnings("unchecked") public T sql(String sqlStatement) { this.sqlStatement = sqlStatement; return (T) this; } @SuppressWarnings("unchecked") public T parameter(String name, Object value) { parameters.put(name, value); return (T) this; } @SuppressWarnings("unchecked") public U singleResult() { this.resultType = ResultType.SINGLE_RESULT; if (commandExecutor != null) { return (U) commandExecutor.execute(this); } return executeSingleResult(Context.getCommandContext()); } @SuppressWarnings("unchecked") public List<U> list() { this.resultType = ResultType.LIST; if (commandExecutor != null) { return (List<U>) commandExecutor.execute(this); } return executeList(Context.getCommandContext(), getParameterMap(), 0, Integer.MAX_VALUE); } @SuppressWarnings("unchecked") public List<U> listPage(int firstResult, int maxResults) { this.firstResult = firstResult; this.maxResults = maxResults; this.resultType = ResultType.LIST_PAGE; if (commandExecutor != null) { return (List<U>) commandExecutor.execute(this); } return executeList(Context.getCommandContext(), getParameterMap(), firstResult, maxResults); } public long count() { this.resultType = ResultType.COUNT; if (commandExecutor != null) { return (Long) commandExecutor.execute(this); } return executeCount(Context.getCommandContext(), getParameterMap()); } public Object execute(CommandContext commandContext) { if (resultType == ResultType.LIST) { return executeList(commandContext, getParameterMap(), 0, Integer.MAX_VALUE); } else if (resultType == ResultType.LIST_PAGE) { Map<String, Object> parameterMap = getParameterMap(); parameterMap.put("resultType", "LIST_PAGE"); parameterMap.put("firstResult", firstResult); parameterMap.put("maxResults", maxResults); if (StringUtils.isNotBlank(ObjectUtils.toString(parameterMap.get("orderBy")))) { parameterMap.put("orderBy", "RES." + parameterMap.get("orderBy")); } else { parameterMap.put("orderBy", "RES.ID_ asc"); } int firstRow = firstResult + 1; parameterMap.put("firstRow", firstRow); int lastRow = 0; if (maxResults == Integer.MAX_VALUE) { lastRow = maxResults; } lastRow = firstResult + maxResults + 1; parameterMap.put("lastRow", lastRow); return executeList(commandContext, parameterMap, firstResult, maxResults); } else if (resultType == ResultType.SINGLE_RESULT) { return executeSingleResult(commandContext); } else { return executeCount(commandContext, getParameterMap()); } } public abstract long executeCount(CommandContext commandContext, Map<String, Object> parameterMap); /** * Executes the actual query to retrieve the list of results. * @param maxResults * @param firstResult * * @param page * used if the results must be paged. If null, no paging will be * applied. */ public abstract List<U> executeList(CommandContext commandContext, Map<String, Object> parameterMap, int firstResult, int maxResults); public U executeSingleResult(CommandContext commandContext) { List<U> results = executeList(commandContext, getParameterMap(), 0, Integer.MAX_VALUE); if (results.size() == 1) { return results.get(0); } else if (results.size() > 1) { throw new ActivitiException("Query return " + results.size() + " results instead of max 1"); } return null; } private Map<String, Object> getParameterMap() { HashMap<String, Object> parameterMap = new HashMap<String, Object>(); parameterMap.put("sql", sqlStatement); parameterMap.putAll(parameters); return parameterMap; } public Map<String, Object> getParameters() { return parameters; } }