001: /* ====================================================================
002: * The LateralNZ Software License, Version 1.0
003: *
004: * Copyright (c) 2003 LateralNZ. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above copyright
011: * notice, this list of conditions and the following disclaimer.
012: *
013: * 2. Redistributions in binary form must reproduce the above copyright
014: * notice, this list of conditions and the following disclaimer in
015: * the documentation and/or other materials provided with the
016: * distribution.
017: *
018: * 3. The end-user documentation included with the redistribution,
019: * if any, must include the following acknowledgment:
020: * "This product includes software developed by
021: * LateralNZ (http://www.lateralnz.org/) and other third parties."
022: * Alternately, this acknowledgment may appear in the software itself,
023: * if and wherever such third-party acknowledgments normally appear.
024: *
025: * 4. The names "LateralNZ" must not be used to endorse or promote
026: * products derived from this software without prior written
027: * permission. For written permission, please
028: * contact oss@lateralnz.org.
029: *
030: * 5. Products derived from this software may not be called "Panther",
031: * or "Lateral" or "LateralNZ", nor may "PANTHER" or "LATERAL" or
032: * "LATERALNZ" appear in their name, without prior written
033: * permission of LateralNZ.
034: *
035: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
036: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
037: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
038: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
039: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
040: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
041: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
042: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
043: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
044: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
045: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
046: * SUCH DAMAGE.
047: * ====================================================================
048: *
049: * This software consists of voluntary contributions made by many
050: * individuals on behalf of LateralNZ. For more
051: * information on Lateral, please see http://www.lateralnz.com/ or
052: * http://www.lateralnz.org
053: *
054: */
055: package org.lateralnz.common.util;
056:
057: import java.util.ArrayList;
058: import java.util.HashMap;
059:
060: /**
061: * a way to ensure that certain singletons and other objects which
062: * should not be garbage collected, are not. This runs as a sleeping
063: * thread, and stores objects in a list -- they can never be retrieved
064: * since this should not be used as a retrieval mechanism
065: *
066: * @author J R Briggs
067: */
068: public final class ObjRefUtils extends Thread {
069: private static ObjRefUtils obj = null;
070:
071: public ArrayList objects = new ArrayList();
072: public HashMap namedobjects = new HashMap();
073: boolean running = true;
074:
075: private ObjRefUtils() {
076: }
077:
078: /**
079: * get the singleton instance of this class
080: */
081: public static ObjRefUtils getInstance() {
082: if (obj == null) {
083: synchronized (ObjRefUtils.class) {
084: if (obj == null) {
085: obj = new ObjRefUtils();
086: }
087: }
088: }
089:
090: return obj;
091: }
092:
093: /**
094: * sleep forever
095: */
096: public void run() {
097: while (running) {
098: try {
099: Thread.sleep(Long.MAX_VALUE);
100: } catch (InterruptedException ie) {
101: }
102: }
103: }
104:
105: /**
106: * add an object to be remembered
107: */
108: public void add(Object o) {
109: objects.add(o);
110: }
111:
112: public Object get(String name) {
113: return namedobjects.get(name);
114: }
115:
116: public void set(String name, Object obj) {
117: namedobjects.put(name, obj);
118: }
119: }
|