/*******************************************************************************
* Copyright (c) 2005, 2009 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*
*******************************************************************************/
package org.eclipse.jst.jsp.core.internal.taglib;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jst.jsp.core.internal.Logger;
/**
* A simple cache for TaglibHelpers to avoid excessive creation of TaglibClassLoaders
* @author pavery
*/
class TaglibHelperCache {
private static final boolean DEBUG;
static {
String value = Platform.getDebugOption("org.eclipse.jst.jsp.core/debug/taglibvars"); //$NON-NLS-1$
DEBUG = value != null && value.equalsIgnoreCase("true"); //$NON-NLS-1$
}
/**
* An entry for the cache (projectPath string & TaglibHelper)
*/
class Entry {
private TaglibHelper fHelper;
private String fProjectName;
public Entry(String projectName, TaglibHelper helper) {
setProjectName(projectName);
setHelper(helper);
}
public TaglibHelper getHelper() {
return fHelper;
}
public void setHelper(TaglibHelper helper) {
fHelper = helper;
}
public String getProjectName() {
return fProjectName;
}
public void setProjectName(String projectName) {
fProjectName = projectName;
}
public String toString() {
return "Taglib Helper Entry [" + getProjectName() + "]"; //$NON-NLS-1$ //$NON-NLS-2$
}
}
private List fHelpers;
// max size for the cache
private int MAX_SIZE;
/**
* Not intended to be large since underlying implmementation uses
* a List.
*/
public TaglibHelperCache(int size) {
MAX_SIZE = size;
fHelpers = Collections.synchronizedList(new ArrayList(MAX_SIZE));
}
/**
*
* @param projectPath
* @param f
* @param mq
* @return
*/
public final synchronized TaglibHelper getHelper(IProject project) {
TaglibHelper helper = null;
Entry entry = null;
String projectName = project.getName();
int size = fHelpers.size();
// fist check for existing
for (int i=0; i<size; i++) {
entry = (Entry)fHelpers.get(i);
if(entry.getProjectName().equals(projectName)) {
// exists
helper = entry.getHelper();
// only move to front if it's not the first entry
if(i>0) {
fHelpers.remove(entry);
fHelpers.add(1, entry);
if(DEBUG) {
Logger.log(Logger.INFO, "(->) TaglibHelperCache moved: " + entry + " to the front of the list"); //$NON-NLS-1$ //$NON-NLS-2$
printCacheContents();
}
}
break;
}
}
// didn't exist
if(helper == null) {
helper = createNewHelper(projectName, project);
}
return helper;
}
/**
* @param projectName
* @param f
* @param mq
* @return
*/
private TaglibHelper createNewHelper(String projectName, IProject project) {
TaglibHelper helper;
// create
helper = new TaglibHelper(project);
Entry newEntry = new Entry(projectName, helper);
fHelpers.add(0, newEntry);
if(DEBUG) {
Logger.log(Logger.INFO, "(+) TaglibHelperCache added: " + newEntry); //$NON-NLS-1$
printCacheContents();
}
if(fHelpers.size() > MAX_SIZE) {
// one too many, remove last
Entry removed = (Entry) fHelpers.remove(fHelpers.size()-1);
removed.getHelper().dispose();
if(DEBUG) {
Logger.log(Logger.INFO, "(-) TaglibHelperCache removed: " + removed.getProjectName()); //$NON-NLS-1$
printCacheContents();
}
}
return helper;
}
public final synchronized void removeHelper(String projectName) {
Entry entry = null;
Iterator it = fHelpers.iterator();
while(it.hasNext()) {
entry = (Entry)it.next();
if(entry.getProjectName().equals(projectName)) {
entry.getHelper().dispose();
fHelpers.remove(entry);
if(DEBUG) {
Logger.log(Logger.INFO, "(-) TaglibHelperCache removed: " + entry); //$NON-NLS-1$
printCacheContents();
}
break;
}
}
}
public final synchronized void invalidate(String projectName, String className) {
Entry entry = null;
Iterator it = fHelpers.iterator();
while(it.hasNext()) {
entry = (Entry)it.next();
if(entry.getProjectName().equals(projectName)) {
entry.getHelper().invalidateClass(className);
if(DEBUG) {
Logger.log(Logger.INFO, "(-) TaglibHelperCache invalidated: " + className); //$NON-NLS-1$
printCacheContents();
}
break;
}
}
}
private void printCacheContents() {
StringBuffer debugString = new StringBuffer();
debugString.append("\n-----------------------------------------------------------"); //$NON-NLS-1$
debugString.append("\ncache contents:"); //$NON-NLS-1$
for (int i=0; i<fHelpers.size(); i++)
debugString.append("\n -" + i + "- " + fHelpers.get(i)); //$NON-NLS-1$ //$NON-NLS-2$
debugString.append("\n-----------------------------------------------------------"); //$NON-NLS-1$
Logger.log(Logger.INFO, debugString.toString());
}
}