/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* 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://glassfish.dev.java.net/public/CDDL+GPL.html
* or glassfish/bootstrap/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 glassfish/bootstrap/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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*
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*
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
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* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
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*/
package com.sun.enterprise.util;
import java.util.Hashtable;
import java.util.Vector;
//START OF IASRI 4660742
import java.util.logging.*;
import com.sun.logging.*;
//END OF IASRI 4660742
public abstract class ResourceCache
{
// START OF IASRI 4660742
static Logger _logger=LogDomains.getLogger(LogDomains.UTIL_LOGGER);
// END OF IASRI 4660742
/**
*
*/
public ResourceCache(int count)
{
resources = new Hashtable();
this.count = count;
}
/**
* @exception Exception on exception
*/
public Object getResource(Object name) throws Exception
{
Object resource = null;
Vector list = null;
Resource r = null;
// get the list of resources
synchronized (resources) {
list = (Vector) resources.get(name);
if (list == null) {
list = new Vector(count);
resources.put(name, list);
}
}
// check for available resource
boolean newR = false; // this thread needs to create a new resource
synchronized (list) {
while (resource == null) {
// try to find an available resource
for (int i=0; i < list.size(); i++) {
if ((r = (Resource) list.elementAt(i)).isAvailable()) {
r.markInUse();
resource = r.getResource();
break;
}
}
// create new resource if limit not reached
if (resource == null) {
if (list.size() < count) {
r = new Resource();
list.addElement(r);
newR = true;
break;
}
// wait for the resource to free up
if (!newR) list.wait();
}
}
}
// if new resource created, initialize the resource
if (newR) {
try {
resource = createResource(name);
// XXX need to handle case when resource is null
} catch (Exception ex) {
/** IASRI 4660742
ex.printStackTrace();
**/
// START OF IASRI 4660742
_logger.log(Level.SEVERE,"enterprise_util.excep_rescache_getres",ex);
// END OF IASRI 4660742
}
synchronized (list) {
r.setResource(resource);
r.markInUse();
}
}
return resource;
}
/**
*
*/
public void returnResource(Object name, Object oldResource,
Object newResource)
{
Resource r = null;
Vector list = (Vector) resources.get(name);
if (list != null) {
synchronized (list) {
for (int i=0; i < list.size(); i++) {
r = (Resource) list.elementAt(i);
if (r.getResource() == oldResource) {
r.setResource(newResource);
r.markAvailable();
list.notifyAll();
break;
}
}
}
}
}
/**
* Typically a long operation.
*
* @exception Exception on exception
*/
public abstract Object createResource(Object name) throws Exception;
private Hashtable resources;
private int count;
}
/**
*
*/
class Resource
{
private static final int IN_USE=1;
private static final int AVAILABLE=2;
private static final int NOT_AVAILABLE=3;
private Object resource;
private int state;
/**
*
*/
Resource()
{
resource = null;
state = NOT_AVAILABLE;
}
/**
*
*/
Object getResource()
{
return resource;
}
/**
*
*/
void setResource(Object resource)
{
this.resource = resource;
}
/**
*
*/
void markAvailable()
{
state = AVAILABLE;
}
/**
*
*/
void markInUse()
{
state = IN_USE;
}
/**
*
*/
boolean isAvailable()
{
return (state == AVAILABLE) ? true : false;
}
}