Java examples for Reflection:Property
Returns the property descriptors of a class or an interface.
/*//w w w.ja va 2s .co m * Copyright 2000-2014 Vaadin Ltd. * * 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.java2s; import java.beans.BeanInfo; import java.beans.IntrospectionException; import java.beans.Introspector; import java.beans.PropertyDescriptor; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.List; public class Main { public static void main(String[] argv) throws Exception { Class beanClass = String.class; System.out.println(getBeanPropertyDescriptor(beanClass)); } /** * Returns the property descriptors of a class or an interface. * * For an interface, superinterfaces are also iterated as Introspector does * not take them into account (Oracle Java bug 4275879), but in that case, * both the setter and the getter for a property must be in the same * interface and should not be overridden in subinterfaces for the discovery * to work correctly. * * NOTE : This utility method relies on introspection (and returns * PropertyDescriptor) which is a part of java.beans package. The latter * package could require bigger JDK in the future (with Java 9+). So it may * be changed in the future. * * For interfaces, the iteration is depth first and the properties of * superinterfaces are returned before those of their subinterfaces. * * @param beanClass * @return * @throws IntrospectionException */ public static List<PropertyDescriptor> getBeanPropertyDescriptor( final Class<?> beanClass) throws IntrospectionException { // Oracle bug 4275879: Introspector does not consider superinterfaces of // an interface if (beanClass.isInterface()) { List<PropertyDescriptor> propertyDescriptors = new ArrayList<PropertyDescriptor>(); for (Class<?> cls : beanClass.getInterfaces()) { propertyDescriptors.addAll(getBeanPropertyDescriptor(cls)); } BeanInfo info = Introspector.getBeanInfo(beanClass); propertyDescriptors.addAll(getPropertyDescriptors(info)); return propertyDescriptors; } else { BeanInfo info = Introspector.getBeanInfo(beanClass); return getPropertyDescriptors(info); } } private static List<PropertyDescriptor> getPropertyDescriptors( BeanInfo beanInfo) { PropertyDescriptor[] descriptors = beanInfo .getPropertyDescriptors(); List<PropertyDescriptor> result = new ArrayList<PropertyDescriptor>( descriptors.length); for (PropertyDescriptor descriptor : descriptors) { try { Method readMethod = getMethodFromBridge(descriptor .getReadMethod()); if (readMethod != null) { Method writeMethod = getMethodFromBridge( descriptor.getWriteMethod(), readMethod.getReturnType()); if (writeMethod == null) { writeMethod = descriptor.getWriteMethod(); } PropertyDescriptor descr = new PropertyDescriptor( descriptor.getName(), readMethod, writeMethod); result.add(descr); } else { result.add(descriptor); } } catch (SecurityException ignore) { // handle next descriptor } catch (IntrospectionException e) { result.add(descriptor); } } return result; } /** * Return declared method for which {@code bridgeMethod} is generated. If * {@code bridgeMethod} is not a bridge method then return null. */ private static Method getMethodFromBridge(Method bridgeMethod) throws SecurityException { if (bridgeMethod == null) { return null; } return getMethodFromBridge(bridgeMethod, bridgeMethod.getParameterTypes()); } /** * Return declared method for which {@code bridgeMethod} is generated using * its {@code paramTypes}. If {@code bridgeMethod} is not a bridge method * then return null. */ private static Method getMethodFromBridge(Method bridgeMethod, Class<?>... paramTypes) throws SecurityException { if (bridgeMethod == null || !bridgeMethod.isBridge()) { return null; } try { return bridgeMethod.getDeclaringClass().getMethod( bridgeMethod.getName(), paramTypes); } catch (NoSuchMethodException e) { return null; } } }