Java examples for Reflection:Property
Sets an attribute on the passed object instance.
/**/*from w w w . j a v a 2 s . c o m*/ * Helios, OpenSource Monitoring * Brought to you by the Helios Development Group * * Copyright 2007, Helios Development Group and individual contributors * as indicated by the @author tags. See the copyright.txt file in the * distribution for a full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. * */ //package com.java2s; import java.beans.*; import java.util.ArrayList; import java.util.List; public class Main { public static void main(String[] argv) throws Exception { String name = "java2s.com"; String value = "java2s.com"; Object target = "java2s.com"; setAttribute(name, value, target); } /** * Sets an attribute on the passed object instance. * @param name The name of the attribute. * @param value The string value. * @param target The object instance to set on. */ public static void setAttribute(String name, String value, Object target) { try { Class<?> targetType = getAttributeType(target.getClass(), name); PropertyEditor propertyEditor = PropertyEditorManager .findEditor(targetType); if (propertyEditor == null) throw new RuntimeException( "No PropertyEditor Found for type [" + targetType.getName() + "] in object of type + [" + target.getClass().getName() + "]"); propertyEditor.setAsText(value); Object typedValue = propertyEditor.getValue(); Expression expression = new Expression(target, getPropertyDescriptor(target.getClass(), name) .getWriteMethod().getName(), new Object[] { typedValue }); expression.execute(); } catch (Exception e) { throw new RuntimeException("Failed to set attribute [" + name + "] on instance of [" + target.getClass().getName() + "]"); } } /** * Determines the type of the named parameter for the passed type. * @param targetType The target type to invoke against. * @param name The attribute name. * @return The class of the parameter type */ public static Class<?> getAttributeType(Class<?> targetType, String name) { PropertyDescriptor pd = getPropertyDescriptor(targetType, name); return pd.getPropertyType(); } /** * Locates the PropertyDescriptor for the passed name in the passed class. * @param targetType * @param name * @return A PropertyDescriptor */ public static PropertyDescriptor getPropertyDescriptor( Class<?> targetType, String name) { String dName = Introspector.decapitalize(name); try { BeanInfo bi = Introspector.getBeanInfo(targetType); for (PropertyDescriptor pd : bi.getPropertyDescriptors()) { if (pd.getName().equals(dName)) { return pd; } } throw new Exception("No PropertyDescriptor found for " + name); } catch (Exception e) { throw new RuntimeException( "Failed to Acquire PropertyDescriptor for [" + targetType.getName() + "/" + name + "]", e); } } public static BeanInfo getBeanInfo(Object pojo) { try { return Introspector.getBeanInfo(pojo.getClass()); } catch (Exception e) { throw new RuntimeException("Failed to create bean info", e); } } /** * Returns a list of a pojo's <code>PropertyDescriptor</code>s minus the same for <code>java.lang.Object</code>. * @param pojo * @return A list of <code>PropertyDescriptor</code>s. */ public static List<PropertyDescriptor> getPropertyDescriptors( Object pojo) { List<PropertyDescriptor> list = getAllPropertyDescriptors(pojo); List<PropertyDescriptor> objList = getAllPropertyDescriptors(new Object()); list.removeAll(objList); return list; } /** * Returns a list of all of a pojo's <code>PropertyDescriptor</code>s * @param pojo * @return A list of <code>PropertyDescriptor</code>s. */ public static List<PropertyDescriptor> getAllPropertyDescriptors( Object pojo) { List<PropertyDescriptor> list = new ArrayList<PropertyDescriptor>(); BeanInfo bi = getBeanInfo(pojo); for (PropertyDescriptor pd : bi.getPropertyDescriptors()) { list.add(pd); } return list; } }