Retrieves a property descriptor object for a given property. - Java Reflection

Java examples for Reflection:Property

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Description

Retrieves a property descriptor object for a given property.

Demo Code

/*//w ww . j a  v  a2s . c o m
 * The contents of this file are subject to the Sapient Public License
 * Version 1.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 * http://carbon.sf.net/License.html.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
 * the specific language governing rights and limitations under the License.
 *
 * The Original Code is The Carbon Component Framework.
 *
 * The Initial Developer of the Original Code is Sapient Corporation
 *
 * Copyright (C) 2003 Sapient Corporation. All Rights Reserved.
 */
//package com.java2s;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;

public class Main {
    public static void main(String[] argv) throws Exception {
        String propertyName = "java2s.com";
        Class beanClass = String.class;
        System.out.println(getPropertyDescriptor(propertyName, beanClass));
    }

    /**
     * Retrieves a property descriptor object for a given property.
     * <p>
     * Uses the classes in <code>java.beans</code> to get back
     * a descriptor for a property.  Read-only and write-only
     * properties will have a slower return time.
     * </p>
     *
     * @param propertyName The programmatic name of the property
     * @param beanClass The Class object for the target bean.
     *                  For example sun.beans.OurButton.class.
     * @return a PropertyDescriptor for a property that follows the
     *         standard Java naming conventions.
     * @throws PropertyNotFoundException indicates that the property
     *         could not be found on the bean class.
     */
    private static final PropertyDescriptor getPropertyDescriptor(
            String propertyName, Class beanClass) {

        PropertyDescriptor resultPropertyDescriptor = null;

        char[] pNameArray = propertyName.toCharArray();
        pNameArray[0] = Character.toLowerCase(pNameArray[0]);
        propertyName = new String(pNameArray);

        try {
            resultPropertyDescriptor = new PropertyDescriptor(propertyName,
                    beanClass);
        } catch (IntrospectionException e1) {
            // Read-only and write-only properties will throw this
            // exception.  The properties must be looked up using
            // brute force.

            // This will get the list of all properties and iterate
            // through looking for one that matches the property
            // name passed into the method.
            try {
                BeanInfo beanInfo = Introspector.getBeanInfo(beanClass);

                PropertyDescriptor[] propertyDescriptors = beanInfo
                        .getPropertyDescriptors();

                for (int i = 0; i < propertyDescriptors.length; i++) {
                    if (propertyDescriptors[i].getName().equals(
                            propertyName)) {

                        // If the names match, this this describes the
                        // property being searched for.  Break out of
                        // the iteration.
                        resultPropertyDescriptor = propertyDescriptors[i];
                        break;
                    }
                }
            } catch (IntrospectionException e2) {
                e2.printStackTrace();
            }
        }

        // If no property descriptor was found, then this bean does not
        // have a property matching the name passed in.
        if (resultPropertyDescriptor == null) {
            System.out.println("resultPropertyDescriptor == null");
        }

        return resultPropertyDescriptor;
    }
}

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