Returns an alpha sorted string array of a pojo's attribute names. - Java Reflection

Java examples for Reflection:Property

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Description

Returns an alpha sorted string array of a pojo's attribute names.

Demo Code

/**//from   ww w .j  a v  a 2s .  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.Collections;
import java.util.List;

public class Main {
    public static void main(String[] argv) throws Exception {
        Object pojo = "java2s.com";
        System.out.println(java.util.Arrays
                .toString(getPojoAttributeTypes(pojo)));
    }

    /**
     * Returns an alpha sorted string array of a pojo's attribute names.
     * @param pojo
     * @return A string array of attribute names.
     */
    public static String[] getPojoAttributeTypes(Object pojo) {
        List<String> list = new ArrayList<String>();
        for (PropertyDescriptor pd : getPropertyDescriptors(pojo)) {
            if (pd.getReadMethod() != null) {
                list.add(pd.getReadMethod().getReturnType().getName());
            } else {
                list.add(pd.getWriteMethod().getReturnType().getName());
            }
        }
        Collections.sort(list);
        return list.toArray(new String[list.size()]);
    }

    /**
     * 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;
    }

    public static BeanInfo getBeanInfo(Object pojo) {
        try {
            return Introspector.getBeanInfo(pojo.getClass());
        } catch (Exception e) {
            throw new RuntimeException("Failed to create bean info", e);
        }
    }
}

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