Java tutorial
/* * Copyright 2004-2006 the original author or authors. * * 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 org.compass.core.accessor; import java.beans.Introspector; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.compass.core.CompassException; import org.compass.core.util.ClassUtils; /** * Accesses property values via a get/set pair, which may be nonpublic. The * default (and recommended strategy). * <p> * Initial version taken from hibernate. * </p> * * @author kimchy */ public class BasicPropertyAccessor implements PropertyAccessor { private static final Log log = LogFactory.getLog(BasicPropertyAccessor.class); public static final class BasicSetter implements Setter { private static final long serialVersionUID = 3979266932753381168L; private Class clazz; private final transient Method method; private final String propertyName; private BasicSetter(Class clazz, Method method, String propertyName) { this.clazz = clazz; this.method = method; this.propertyName = propertyName; } public void set(Object target, Object value) throws CompassException { try { method.invoke(target, value); } catch (NullPointerException npe) { if (value == null && method.getParameterTypes()[0].isPrimitive()) { throw new PropertyAccessException(npe, "Null value was assigned to a property of primitive type", true, clazz, propertyName); } else { throw new PropertyAccessException(npe, "NullPointerException occurred while calling", true, clazz, propertyName); } } catch (InvocationTargetException ite) { throw new PropertyAccessException(ite, "Exception occurred inside", true, clazz, propertyName); } catch (IllegalAccessException iae) { throw new PropertyAccessException(iae, "IllegalAccessException occurred while calling", true, clazz, propertyName); // cannot occur } catch (IllegalArgumentException iae) { if (value == null && method.getParameterTypes()[0].isPrimitive()) { throw new PropertyAccessException(iae, "Null value was assigned to a property of primitive type", true, clazz, propertyName); } else { log.error("IllegalArgumentException in class [" + clazz.getName() + "], setter method of property [" + propertyName + "]"); log.error("expected type [" + method.getParameterTypes()[0].getName() + "], actual value [" + (value == null ? null : value.getClass().getName()) + "]"); throw new PropertyAccessException(iae, "IllegalArgumentException occurred while calling", true, clazz, propertyName); } } } public String getName() { return propertyName; } public Method getMethod() { return method; } public String getMethodName() { return method.getName(); } Object readResolve() { return createSetter(clazz, propertyName); } public String toString() { return "BasicSetter(" + clazz.getName() + '.' + propertyName + ')'; } } public static final class BasicGetter implements Getter { private static final long serialVersionUID = 3978701788020880176L; private Class clazz; private final transient Method method; private final String propertyName; private BasicGetter(Class clazz, Method method, String propertyName) { this.clazz = clazz; this.method = method; this.propertyName = propertyName; } public Object get(Object target) throws CompassException { try { return method.invoke(target); } catch (InvocationTargetException ite) { throw new PropertyAccessException(ite, "Exception occurred inside", false, clazz, propertyName); } catch (IllegalAccessException iae) { throw new PropertyAccessException(iae, "IllegalAccessException occurred while calling", false, clazz, propertyName); // cannot occur } catch (IllegalArgumentException iae) { log.error("IllegalArgumentException in class [" + clazz.getName() + "], getter method of property [" + propertyName + "]"); throw new PropertyAccessException(iae, "IllegalArgumentException occurred calling", false, clazz, propertyName); } } public String getName() { return propertyName; } public Class getReturnType() { return method.getReturnType(); } public Method getMethod() { return this.method; } public String toString() { return "BasicGetter(" + clazz.getName() + '.' + propertyName + ')'; } Object readResolve() { return createGetter(clazz, propertyName); } } public Setter getSetter(Class theClass, String propertyName) throws PropertyNotFoundException { return getSetterOrNull(theClass, propertyName); } private static Setter createSetter(Class theClass, String propertyName) throws PropertyNotFoundException { BasicSetter result = getSetterOrNull(theClass, propertyName); if (result == null) { throw new PropertyNotFoundException("Could not find a setter for property [" + propertyName + "] in class [" + theClass.getName() + "]"); } return result; } private static BasicSetter getSetterOrNull(Class theClass, String propertyName) { if (theClass == Object.class || theClass == null) return null; Method method = setterMethod(theClass, propertyName); if (method != null) { if (!ClassUtils.isPublic(theClass, method)) { method.setAccessible(true); } return new BasicSetter(theClass, method, propertyName); } else { BasicSetter setter = getSetterOrNull(theClass.getSuperclass(), propertyName); if (setter == null) { Class[] interfaces = theClass.getInterfaces(); for (int i = 0; setter == null && i < interfaces.length; i++) { setter = getSetterOrNull(interfaces[i], propertyName); } } return setter; } } private static Method setterMethod(Class theClass, String propertyName) { BasicGetter getter = getGetterOrNull(theClass, propertyName); Class returnType = (getter == null) ? null : getter.getReturnType(); Method[] methods = theClass.getDeclaredMethods(); Method potentialSetter = null; for (Method method : methods) { String methodName = method.getName(); if (method.getParameterTypes().length == 1 && methodName.startsWith("set")) { String testStdMethod = Introspector.decapitalize(methodName.substring(3)); String testOldMethod = methodName.substring(3); if (testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName)) { potentialSetter = method; if (returnType == null || method.getParameterTypes()[0].equals(returnType)) return potentialSetter; } } } return potentialSetter; } public Getter getGetter(Class theClass, String propertyName) throws PropertyNotFoundException { return createGetter(theClass, propertyName); } public static Getter createGetter(Class theClass, String propertyName) throws PropertyNotFoundException { BasicGetter result = getGetterOrNull(theClass, propertyName); if (result == null) { throw new PropertyNotFoundException( "Could not find a getter for " + propertyName + " in class " + theClass.getName()); } return result; } private static BasicGetter getGetterOrNull(Class theClass, String propertyName) { if (theClass == Object.class || theClass == null) return null; Method method = getterMethod(theClass, propertyName); if (method != null) { if (!ClassUtils.isPublic(theClass, method)) method.setAccessible(true); return new BasicGetter(theClass, method, propertyName); } else { BasicGetter getter = getGetterOrNull(theClass.getSuperclass(), propertyName); if (getter == null) { Class[] interfaces = theClass.getInterfaces(); for (int i = 0; getter == null && i < interfaces.length; i++) { getter = getGetterOrNull(interfaces[i], propertyName); } } return getter; } } private static Method getterMethod(Class theClass, String propertyName) { Method[] methods = theClass.getDeclaredMethods(); for (Method method : methods) { // only carry on if the method has no parameters if (method.getParameterTypes().length == 0) { String methodName = method.getName(); // try "get" if (methodName.startsWith("get")) { String testStdMethod = Introspector.decapitalize(methodName.substring(3)); String testOldMethod = methodName.substring(3); if (testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName)) return method; } // if not "get" then try "is" /* * boolean isBoolean = * methods[i].getReturnType().equals(Boolean.class) || * methods[i].getReturnType().equals(boolean.class); */ if (methodName.startsWith("is")) { String testStdMethod = Introspector.decapitalize(methodName.substring(2)); String testOldMethod = methodName.substring(2); if (testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName)) return method; } } } return null; } }