Java tutorial
/* * Copyright 2005-2010 The Kuali Foundation * * Licensed under the Educational Community 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.osedu.org/licenses/ECL-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 org.kuali.kra.budget.calculator.query; import java.lang.reflect.InvocationTargetException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.commons.beanutils.PropertyUtils; import org.kuali.kra.budget.calculator.QueryList; /** * Contains different sets of Data Collection * in Hashtable. can execute query to get a * subSets of the Data Collection or * can add, update and delete data to a Data Collection. * This class is a Singleton since it has to be * accessed globally. */ public class QueryEngine { private Map dataCollection; /** Creates a new instance of QueryEngine */ public QueryEngine() { dataCollection = new HashMap(); } /** returns a subset of Data Collection. This subset is got by applying the * operator parameter. Operator can be a combination of multiple logical and * relational conditions. * @return Query List * @param beanClass bean Class * @param key dataCollection key * @param operator Operator * @CoeusException */ public QueryList executeQuery(Class beanClass, Operator operator) { List dataList = (List) dataCollection.get(beanClass); if (dataList == null) return new QueryList(); return cloneListData(new QueryList(dataList).filter(operator)); } /** * returns a subset of Data Collection. This subset is got by applying the * operator parameter. Operator can be a combination of multiple logical and * relational conditions. * @return returns results in this Query List * @param collectionKey collection key * @param key data key * @param operator Operator */ public QueryList executeQuery(Object key, Operator operator) { List dataList = (List) dataCollection.get(key); if (dataList == null) return new QueryList(); return cloneListData(new QueryList(dataList).filter(operator)); } /** * returns a subset of Data Collection. This subset is got by applying the * operator parameter. Operator can be a combination of multiple logical and * relational conditions. * @return returns results in this Query List * @param collectionKey collection key * @param key data key * @param operator Operator */ public QueryList executeQuery(List dataList, Operator operator) { if (dataList == null) return new QueryList(); return cloneListData(new QueryList(dataList).filter(operator)); } /** returns a clone(copy) of dataList which is passed as the parameter. * @param queryList QueryList * @CoeusException * @return QueryList */ public QueryList cloneListData(QueryList queryList) { QueryList resultClone = new QueryList(); if (queryList == null) return resultClone; //return the clone not the original instances for (int index = 0; index < queryList.size(); index++) { resultClone.add(ObjectCloner.deepCopy(queryList.get(index))); } return resultClone; } /** returna all beans of this Class type * @return QueryList * @param key dataCollection key * @param beanClass beanClass * @CoeusException */ public QueryList getDetails(Object key, Class beanClass) { List dataList = (List) dataCollection.get(beanClass); if (dataList == null) return new QueryList(); return cloneListData(new QueryList(dataList)); } /** returna all beans of this Class type * @return QueryList * @param key dataCollection key * @param collectionKey collectionKey * @CoeusException */ public QueryList getDetails(Object key, Object collectionKey) { List dataList = (List) dataCollection.get(collectionKey); if (dataList == null) return new QueryList(); return cloneListData(new QueryList(dataList)); } /** adds a DatCollection(i.e. Hashtable) to QueryEngine. * @param key DatCollection key * @param value DataCollection(i.e. Hashtable) */ public void addDataCollection(Object key, List value) { dataCollection.put(key, value); } /** removes a DatCollection(i.e. Hashtable) with the specified key from QueryEngine. * @param key key */ public void removeDataCollection(Object key) { dataCollection.remove(key); } /** adds a CoeusBean to the DataCollection with the specified key * @param baseBean BaseBean * @param key key of the DataCollection */ public void addData(Object baseBean) { List dataList = (List) dataCollection.get(baseBean.getClass()); if (dataList == null) dataCollection.put(baseBean.getClass(), new QueryList()); ((QueryList) dataCollection.get(baseBean.getClass())).add(baseBean); } /** adds a CoeusBean to the DataCollection with the specified key * @param baseBean BaseBean * @param key key of the DataCollection */ public void addData(Object key, Object baseBean) { List dataList = (List) dataCollection.get(key); if (dataList == null) dataCollection.put(key, new ArrayList()); ((List) dataCollection.get(key)).add(baseBean); } /** removes CoeusBean from the DataCollection with the specified key * @param baseBean BaseBean * @param key DataCollection key */ public void removeData(Object baseBean) { List dataList = (List) dataCollection.get(baseBean.getClass()); dataList.remove(baseBean); } /** removes a CoeusBean from the DataCollection with the specified key * @param key DataCollection key * @param beanClass Class type of the bean to locate QueryList from * where the Object has to be removed * @param index index at which the Object has to be removed. */ public void removeData(Class beanClass, int index) { List dataList = (List) dataCollection.get(beanClass); dataList.remove(index); } /** removes a CoeusBean from the DataCollection with the specified key * @param key DataCollection key * @param beanClass Class type of the bean to locate QueryList from * where the Object has to be removed * @param index index at which the Object has to be removed. */ public void removeData(Object key, Operator operator) { if (key == null || operator == null) return; List dataList = (List) dataCollection.get(key); if (dataList == null || dataList.size() == 0) return; Object baseBean = null; for (int index = 0; index < dataList.size(); index++) { baseBean = dataList.get(index); if (baseBean == null) continue; if (operator.getResult(baseBean) == true) { dataList.remove(index); index--; } } } /** Removes bean instances from query engine. * @param key data collection key. * @param beanClass bean class. * @param operator operator. */ public void removeData(Class beanClass, Operator operator) { if (operator == null) return; List dataList = (List) dataCollection.get(beanClass); if (dataList == null || dataList.size() == 0) return; Object baseBean = null; for (int index = 0; index < dataList.size(); index++) { baseBean = dataList.get(index); if (baseBean == null) continue; if (operator.getResult(baseBean) == true) { dataList.remove(index); index--; } } } public void addDataCollection(Object object, String... strings) { for (int i = 0; i < strings.length; i++) { try { List dataList = (List) PropertyUtils.getProperty(object, strings[i]); if (dataList != null && !dataList.isEmpty()) { dataCollection.put(dataList.get(0).getClass(), dataList); } } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } } } }