PropertyUtils.java Source code

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Here is the source code for PropertyUtils.java

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/*
 * Copyright 2004, 2005, 2006 Odysseus Software GmbH
 *
 * 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.
 */

import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * Property access utility methods.
 *
 * @author Christoph Beck
 */
public class PropertyUtils {
    private static HashMap descriptorCache = new HashMap();

    /**
     * Get map with property descriptors for the specified bean class
     */
    private static Map getPropertyDescriptors(Class clazz) {
        HashMap map = (HashMap) descriptorCache.get(clazz);
        if (map == null) {
            BeanInfo beanInfo = null;
            try {
                beanInfo = Introspector.getBeanInfo(clazz);
            } catch (IntrospectionException e) {
                return Collections.EMPTY_MAP;
            }
            PropertyDescriptor[] descriptors = beanInfo.getPropertyDescriptors();
            if (descriptors == null)
                descriptors = new PropertyDescriptor[0];
            map = new HashMap(descriptors.length);
            for (int i = 0; i < descriptors.length; i++)
                map.put(descriptors[i].getName(), descriptors[i]);
            descriptorCache.put(clazz, map);
        }
        return map;
    }

    /**
     * Get property names of the specified bean class
     */
    public static Iterator getPropertyNames(Class clazz) {
        return getPropertyDescriptors(clazz).keySet().iterator();
    }

    /**
     * Get specified property descriptor
     */
    public static PropertyDescriptor getPropertyDescriptor(Class clazz, String property) {
        return (PropertyDescriptor) getPropertyDescriptors(clazz).get(property);
    }

    /**
     * Get specified property value
     */
    public static Object getProperty(Object bean, String property)
            throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        PropertyDescriptor descriptor = getPropertyDescriptor(bean.getClass(), property);
        if (descriptor == null)
            throw new NoSuchMethodException("Cannot find property " + bean.getClass().getName() + "." + property);
        Method method = descriptor.getReadMethod();
        if (method == null)
            throw new NoSuchMethodException("Cannot find getter for " + bean.getClass().getName() + "." + property);
        return method.invoke(bean, null);
    }

    /**
     * Get specified nested property value
     */
    public static Object getNestedProperty(Object bean, String property)
            throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        if (property.indexOf('.') > 0) {
            String[] path = property.split("\\.");
            for (int i = 0; i < path.length && bean != null; i++) {
                bean = getProperty(bean, path[i]);
            }
            return bean;
        } else {
            return getProperty(bean, property);
        }
    }

    /**
     * Set specified property value
     */
    public static void setProperty(Object bean, String property, Object value)
            throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        PropertyDescriptor descriptor = getPropertyDescriptor(bean.getClass(), property);
        if (descriptor == null)
            throw new NoSuchMethodException("Cannot find property " + bean.getClass().getName() + "." + property);
        Method method = descriptor.getWriteMethod();
        if (method == null)
            throw new NoSuchMethodException("Cannot find setter for " + bean.getClass().getName() + "." + property);
        method.invoke(bean, new Object[] { value });
    }

    /**
     * Set nested property given by property path, starting at specified
     * index. Dynamically create beans if necessary. Take care not to
     * leave the bean changed if an exception occurs.
     */
    private static void setNestedPropertyWithCreate(Object bean, String[] path, int start, Object value)
            throws NoSuchMethodException, IllegalAccessException, InvocationTargetException,
            InstantiationException {
        for (int i = start; i < path.length - 1; i++) {
            Object object = getProperty(bean, path[i]);
            if (object == null) {
                PropertyDescriptor descr = getPropertyDescriptor(bean.getClass(), path[i]);
                object = descr.getPropertyType().newInstance();
                setNestedPropertyWithCreate(object, path, i + 1, value);
                setProperty(bean, path[i], object);
                return;
            }
            bean = object;
        }
        setProperty(bean, path[path.length - 1], value);
    }

    /**
     * Set specified nested property value
     */
    public static void setNestedProperty(Object bean, String property, Object value) throws NoSuchMethodException,
            IllegalAccessException, InvocationTargetException, InstantiationException {
        int lastDot = property.lastIndexOf('.');
        if (lastDot > 0) {
            setNestedPropertyWithCreate(bean, property.split("\\."), 0, value);
        } else {
            setProperty(bean, property, value);
        }
    }

}