/*******************************************************************************
* Copyright (c) 2005, 2008 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 org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.jdt.core.ElementChangedEvent;
import org.eclipse.jdt.core.IElementChangedListener;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IJavaElementDelta;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IType;
/**
* Manages creation and caching (ordered MRU) of TaglibHelpers.
* Removes helpers when their classpath changes (so they are rebuilt).
* There is one helper per project (with a specific classpath entry).
*
* @author pavery
*/
public class TaglibHelperManager implements IElementChangedListener {
private static TaglibHelperManager instance = null;
// using a cache of just 3 loaders
private TaglibHelperCache fCache = new TaglibHelperCache(3);
private TaglibHelperManager() {
// use instance
}
public static synchronized TaglibHelperManager getInstance() {
if(instance == null)
instance = new TaglibHelperManager();
return instance;
}
public TaglibHelper getTaglibHelper(IFile f) {
IProject p = f.getProject();
return getHelperFromCache(p);
}
/**
* @param projectPath
*/
private TaglibHelper getHelperFromCache(IProject project) {
return fCache.getHelper(project);
}
/**
* Update classpath for appropriate loader.
* @see org.eclipse.jdt.core.IElementChangedListener#elementChanged(org.eclipse.jdt.core.ElementChangedEvent)
*/
public void elementChanged(ElementChangedEvent event) {
// handle classpath changes
IJavaElementDelta delta = event.getDelta();
if (delta.getElement().getElementType() == IJavaElement.JAVA_MODEL) {
IJavaElementDelta[] changed = delta.getChangedChildren();
for (int i = 0; i < changed.length; i++) {
if ((changed[i].getFlags() & IJavaElementDelta.F_CLASSPATH_CHANGED) != 0 || (changed[i].getFlags() & IJavaElementDelta.F_REORDER) != 0 || (changed[i].getFlags() & IJavaElementDelta.F_RESOLVED_CLASSPATH_CHANGED) != 0 || (changed[i].getFlags() & IJavaElementDelta.F_PRIMARY_RESOURCE) != 0) {
IJavaElement proj = changed[i].getElement();
handleClasspathChange(changed, i, proj);
}
}
}
else if (delta.getElement().getElementType() == IJavaElement.COMPILATION_UNIT) {
IJavaElementDelta[] changed = delta.getChangedChildren();
for (int i = 0; i < changed.length; i++) {
if ((changed[i].getFlags() & IJavaElementDelta.F_SUPER_TYPES) != 0) {
IJavaElement element = changed[i].getElement();
handleSuperTypeChange(element);
}
}
}
}
private void handleSuperTypeChange(IJavaElement element) {
IJavaProject project = element.getJavaProject();
if (element instanceof IType) {
fCache.invalidate(project.getProject().getName(), ((IType) element).getFullyQualifiedName());
}
}
/**
* @param changed
* @param i
* @param proj
*/
private void handleClasspathChange(IJavaElementDelta[] changed, int i, IJavaElement proj) {
if (proj.getElementType() == IJavaElement.JAVA_PROJECT) {
String projectName = ((IJavaProject) proj).getProject().getName();
fCache.removeHelper(projectName);
}
}
}