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Java EE 6 example source code file (MessageHolderSingletonBean.java)

This example Java EE 6 source code file (MessageHolderSingletonBean.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Java EE 6 tags/keywords

date, date, ejb, linkedlist, linkedlist, list, message, message, messageholdersingletonbean, messageholdersingletonbean, servlet, singleton, util, web

The Java EE 6 MessageHolderSingletonBean.java source code

 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://jersey.dev.java.net/CDDL+GPL.html
 * or jersey/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at jersey/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
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package enterprise.messageboard.resources;

import enterprise.messageboard.entities.Message;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import javax.ejb.Singleton;

public class MessageHolderSingletonBean {

    private LinkedList<Message> list = new LinkedList();
    private int maxMessages = 10;

    int currentId = 0;

    public MessageHolderSingletonBean() {
        // initial content
        addMessage("msg0", new Date(0));
        addMessage("msg1", new Date(1000));
        addMessage("msg2", new Date(2000));

    public List<Message> getMessages() {
        List<Message> l = new LinkedList();

        int index = 0;

        while(index < list.size() && index < maxMessages) {

        return l;

    private synchronized int getNewId() {
        return currentId++;

    public synchronized Message addMessage(String msg) {
        return addMessage(msg, new Date());

    private synchronized Message addMessage(String msg, Date date) {
        Message m = new Message(date, msg, getNewId());


        return m;
    public Message getMessage(int uniqueId) {
        int index = 0;
        Message m;

        while(index < list.size()) {
            if((m = list.get(index)).getUniqueId() == uniqueId)
                return m;
        return null;

    public synchronized boolean deleteMessage(int uniqueId) {
        int index = 0;

        while(index < list.size()) {
            if(list.get(index).getUniqueId() == uniqueId) {
                return true;

        return false;

Other Java EE 6 examples (source code examples)

Here is a short list of links related to this Java EE 6 MessageHolderSingletonBean.java source code file:

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