Java tutorial
/** * Copyright (C) 2007 Asterios Raptis * * 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 net.sourceforge.jaulp.lang; import java.io.IOException; import java.io.Serializable; import java.lang.reflect.Array; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import net.sourceforge.jaulp.io.ChangedAttributeResult; import net.sourceforge.jaulp.io.SerializedObjectUtils; import net.sourceforge.jaulp.reflection.ReflectionUtils; import org.apache.commons.beanutils.BeanComparator; import org.apache.commons.beanutils.BeanUtils; import org.apache.log4j.Logger; /** * The Class ObjectUtils provides methods to clone, copy and compare objects. It also provides * methods to find changed data between Objects. */ public final class ObjectUtils { /** The Constant logger. */ private static final Logger logger = Logger.getLogger(ObjectUtils.class.getName()); /** * Try to clone the given object quietly. * * @param object * The object to clone. * @return The cloned object or null if the clone process failed. */ public static Object cloneObjectQuietly(final Object object) { Object clone = null; try { clone = cloneObject(object); } catch (NoSuchMethodException e) { logger.error("Try to clone the object with " + "reflection and call the clone method. " + "Thrown exception: NoSuchMethodException", e); } catch (SecurityException e) { logger.error("Try to clone the object with " + "reflection and call the clone method. " + "Thrown exception: SecurityException", e); } catch (IllegalAccessException e) { logger.error("Try to clone the object with " + "org.apache.commons.beanutils.BeanUtils failed " + "cause of IllegalAccessException. Could not found from ReflectionUtils.", e); } catch (IllegalArgumentException e) { logger.error("Try to clone the object with " + "reflection and call the clone method. " + "Thrown exception: IllegalArgumentException", e); } catch (InvocationTargetException e) { logger.error("Try to clone the object with " + "org.apache.commons.beanutils.BeanUtils failed " + "cause of InvocationTargetException. Could not found from ReflectionUtils.", e); } catch (ClassNotFoundException e) { logger.error("Try to clone the object with " + "org.apache.commons.beanutils.BeanUtils failed " + "cause of ClassNotFoundException. Could not found from ReflectionUtils.", e); } catch (InstantiationException e) { logger.error("Try to clone the object with " + "org.apache.commons.beanutils.BeanUtils failed " + "cause of InstantiationException. Could not found from ReflectionUtils.", e); } catch (IOException e) { logger.error("Try to clone the object with " + "SerializedObjectUtils.copySerializedObject((Serializable)object) " + "cause of IOException.", e); } return clone; } /** * Try to clone the given object. * * @param object * The object to clone. * @return The cloned object or null if the clone process failed. * @throws NoSuchMethodException * the no such method exception * @throws SecurityException * Thrown if the security manager indicates a security violation. * @throws IllegalAccessException * the illegal access exception * @throws IllegalArgumentException * the illegal argument exception * @throws InvocationTargetException * the invocation target exception * @throws ClassNotFoundException * the class not found exception * @throws InstantiationException * the instantiation exception * @throws IOException * Signals that an I/O exception has occurred. */ public static Object cloneObject(final Object object) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, ClassNotFoundException, InstantiationException, IOException { Object clone = null; // Try to clone the object if it implements Serializable. if (object instanceof Serializable) { clone = SerializedObjectUtils.copySerializedObject((Serializable) object); if (clone != null) { return clone; } } // Try to clone the object if it is Cloneble. if (clone == null && object instanceof Cloneable) { if (object.getClass().isArray()) { final Class<?> componentType = object.getClass().getComponentType(); if (componentType.isPrimitive()) { int length = Array.getLength(object); clone = Array.newInstance(componentType, length); while (length-- > 0) { Array.set(clone, length, Array.get(object, length)); } } else { clone = ((Object[]) object).clone(); } if (clone != null) { return clone; } } Class<?> clazz = object.getClass(); Method cloneMethod = clazz.getMethod("clone", (Class[]) null); clone = cloneMethod.invoke(object, (Object[]) null); if (clone != null) { return clone; } } // Try to clone the object by copying all his properties with // the BeanUtils.copyProperties() method. if (clone == null) { clone = ReflectionUtils.getNewInstance(object); BeanUtils.copyProperties(clone, object); } return clone; } /** * Try to clone the given generic object. * * @param <T> * the generic type * @param object * the object to clone * @return The cloned object or null if the clone process failed. */ @SuppressWarnings("unchecked") public static <T> T clone(T object) { return (T) cloneObjectQuietly(object); } /** * Compares the given two objects. * * @param sourceOjbect * the source ojbect * @param objectToCompare * the object to compare * @return true, if successful otherwise false * @throws IllegalAccessException * the illegal access exception * @throws InvocationTargetException * the invocation target exception * @throws NoSuchMethodException * the no such method exception */ @SuppressWarnings("rawtypes") public static boolean compare(Object sourceOjbect, Object objectToCompare) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { if (sourceOjbect == null || objectToCompare == null || !sourceOjbect.getClass().equals(objectToCompare.getClass())) { throw new IllegalArgumentException("Object should not be null and be the same type."); } Map beanDescription = BeanUtils.describe(sourceOjbect); beanDescription.remove("class"); Map clonedBeanDescription = BeanUtils.describe(objectToCompare); clonedBeanDescription.remove("class"); for (Object key : beanDescription.keySet()) { if (compareTo(sourceOjbect, objectToCompare, key.toString()) != 0) { return false; } } return true; } /** * Gets the changed data. * * @param sourceOjbect * the source ojbect * @param objectToCompare * the object to compare * @return the changed data * @throws IllegalAccessException * the illegal access exception * @throws InvocationTargetException * the invocation target exception * @throws NoSuchMethodException * the no such method exception */ @SuppressWarnings("rawtypes") public static List<ChangedAttributeResult> getChangedData(Object sourceOjbect, Object objectToCompare) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { if (sourceOjbect == null || objectToCompare == null || !sourceOjbect.getClass().equals(objectToCompare.getClass())) { throw new IllegalArgumentException("Object should not be null and be the same type."); } Map beanDescription = BeanUtils.describe(sourceOjbect); beanDescription.remove("class"); Map clonedBeanDescription = BeanUtils.describe(objectToCompare); clonedBeanDescription.remove("class"); List<ChangedAttributeResult> changedData = new ArrayList<ChangedAttributeResult>(); for (Object key : beanDescription.keySet()) { if (compareTo(sourceOjbect, objectToCompare, key.toString()) != 0) { Object sourceAttribute = beanDescription.get(key); Object changedAttribute = clonedBeanDescription.get(key); changedData.add(new ChangedAttributeResult(key, sourceAttribute, changedAttribute)); } } return changedData; } /** * Compares the given object over the given property. * * @param sourceOjbect * the source ojbect * @param objectToCompare * the object to compare * @param property * the property * @return the int * @throws IllegalAccessException * the illegal access exception * @throws InvocationTargetException * the invocation target exception * @throws NoSuchMethodException * the no such method exception */ @SuppressWarnings({ "unchecked", "rawtypes" }) public static int compareTo(Object sourceOjbect, Object objectToCompare, String property) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { Map<?, ?> beanDescription = BeanUtils.describe(sourceOjbect); beanDescription.remove("class"); Map<?, ?> clonedBeanDescription = BeanUtils.describe(objectToCompare); clonedBeanDescription.remove("class"); Object sourceAttribute = beanDescription.get(property); Object changedAttribute = clonedBeanDescription.get(property); if (sourceAttribute == null && changedAttribute == null) { return 0; } if (sourceAttribute != null && changedAttribute == null) { return 1; } else if (sourceAttribute == null && changedAttribute != null) { return -1; } return new BeanComparator(property).compare(sourceOjbect, objectToCompare); } /** * Compares the given object over the given property quietly. * * @param sourceOjbect * the source ojbect * @param objectToCompare * the object to compare * @param property * the property * @return the int */ @SuppressWarnings({ "unchecked", "rawtypes" }) public static int compareToQuietly(Object sourceOjbect, Object objectToCompare, String property) { Map<?, ?> beanDescription = null; try { beanDescription = BeanUtils.describe(sourceOjbect); } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) { logger.error("BeanUtils.describe(sourceOjbect) throws an exception...", e); return 0; } beanDescription.remove("class"); Map<?, ?> clonedBeanDescription = null; try { clonedBeanDescription = BeanUtils.describe(objectToCompare); } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) { logger.error("BeanUtils.describe(objectToCompare) throws an exception...", e); return 0; } clonedBeanDescription.remove("class"); Object sourceAttribute = beanDescription.get(property); Object changedAttribute = clonedBeanDescription.get(property); if (sourceAttribute == null && changedAttribute == null) { return 0; } if (sourceAttribute != null && changedAttribute == null) { return 1; } else if (sourceAttribute == null && changedAttribute != null) { return -1; } return new BeanComparator(property).compare(sourceOjbect, objectToCompare); } /** * Compares the given two objects and gets the changed data. * * @param sourceOjbect * the source ojbect * @param objectToCompare * the object to compare * @return the changed data * @throws IllegalAccessException * the illegal access exception * @throws InvocationTargetException * the invocation target exception * @throws NoSuchMethodException * the no such method exception */ @SuppressWarnings("rawtypes") public static Map<Object, ChangedAttributeResult> getChangedDataMap(Object sourceOjbect, Object objectToCompare) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { if (sourceOjbect == null || objectToCompare == null || !sourceOjbect.getClass().equals(objectToCompare.getClass())) { throw new IllegalArgumentException("Object should not be null and be the same type."); } Map beanDescription = BeanUtils.describe(sourceOjbect); beanDescription.remove("class"); Map clonedBeanDescription = BeanUtils.describe(objectToCompare); clonedBeanDescription.remove("class"); Map<Object, ChangedAttributeResult> changedData = new HashMap<Object, ChangedAttributeResult>(); for (Object key : beanDescription.keySet()) { Object sourceAttribute = beanDescription.get(key); Object changedAttribute = clonedBeanDescription.get(key); if (compareTo(sourceOjbect, objectToCompare, key.toString()) != 0) { changedData.put(key, new ChangedAttributeResult(key, sourceAttribute, changedAttribute)); } } return changedData; } /** * Gets the compare to result. * * @param sourceOjbect * the source ojbect * @param objectToCompare * the object to compare * @return the compare to result * @throws IllegalAccessException * the illegal access exception * @throws InvocationTargetException * the invocation target exception * @throws NoSuchMethodException * the no such method exception */ @SuppressWarnings("rawtypes") public static Map<String, Integer> getCompareToResult(Object sourceOjbect, Object objectToCompare) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { if (sourceOjbect == null || objectToCompare == null || !sourceOjbect.getClass().equals(objectToCompare.getClass())) { throw new IllegalArgumentException("Object should not be null and be the same type."); } Map beanDescription = BeanUtils.describe(sourceOjbect); beanDescription.remove("class"); Map clonedBeanDescription = BeanUtils.describe(objectToCompare); clonedBeanDescription.remove("class"); Map<String, Integer> compareResult = new HashMap<String, Integer>(); for (Object key : beanDescription.keySet()) { compareResult.put(key.toString(), Integer.valueOf(compareTo(sourceOjbect, objectToCompare, key.toString()))); } return compareResult; } /** * Private constructor. */ private ObjectUtils() { super(); } /** * Copy the given original object to the given destination object. * * @param <DESTINATION> * the generic type of the destination object. * @param <ORIGINAL> * the generic type of the original object. * @param destination * the destination object. * @param original * the original object. * @throws IllegalAccessException * the illegal access exception * @throws InvocationTargetException * the invocation target exception */ public static final <DESTINATION, ORIGINAL> void copy(DESTINATION destination, ORIGINAL original) throws IllegalAccessException, InvocationTargetException { BeanUtils.copyProperties(destination, original); } /** * Copy quietly the given original object to the given destination object. * * @param <DESTINATION> * the generic type of the destination object. * @param <ORIGINAL> * the generic type of the original object. * @param destination * the destination object. * @param original * the original object. * @return the destination object. */ public static final <DESTINATION, ORIGINAL> DESTINATION copyQuietly(DESTINATION destination, ORIGINAL original) { try { copy(destination, original); } catch (IllegalAccessException e) { return null; } catch (InvocationTargetException e) { return null; } return destination; } /** * Checks if is copyable and copies if its possible otherwise it returns false. * * @param <DESTINATION> * the generic type of the destination object. * @param <ORIGINAL> * the generic type of the original object. * @param destination * the destination object. * @param original * the original object. * @return true, if is copyable otherwise false. */ public static final <DESTINATION, ORIGINAL> boolean isCopyable(DESTINATION destination, ORIGINAL original) { return copyQuietly(destination, original) != null; } }