/*******************************************************************************
* Copyright (c) 2000, 2007 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.aspectj.org.eclipse.jdt.internal.core;
import java.text.NumberFormat;
import java.util.Enumeration;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.aspectj.org.eclipse.jdt.core.IBuffer;
import org.aspectj.org.eclipse.jdt.core.IJavaElement;
import org.aspectj.org.eclipse.jdt.core.IOpenable;
/**
* The buffer manager manages the set of open buffers.
* It implements an LRU cache of buffers.
*/
public class BufferManager {
protected static BufferManager DEFAULT_BUFFER_MANAGER;
protected static boolean VERBOSE;
/**
* LRU cache of buffers. The key and value for an entry
* in the table is the identical buffer.
*/
private BufferCache openBuffers = new BufferCache(60);
/**
* @deprecated
*/
protected org.aspectj.org.eclipse.jdt.core.IBufferFactory defaultBufferFactory = new org.aspectj.org.eclipse.jdt.core.IBufferFactory() {
/**
* @deprecated
*/
public IBuffer createBuffer(IOpenable owner) {
return BufferManager.createBuffer(owner);
}
};
/**
* Adds a buffer to the table of open buffers.
*/
protected void addBuffer(IBuffer buffer) {
if (VERBOSE) {
String owner = ((Openable)buffer.getOwner()).toStringWithAncestors();
System.out.println("Adding buffer for " + owner); //$NON-NLS-1$
}
synchronized (this.openBuffers) {
this.openBuffers.put(buffer.getOwner(), buffer);
}
// close buffers that were removed from the cache if space was needed
this.openBuffers.closeBuffers();
if (VERBOSE) {
System.out.println("-> Buffer cache filling ratio = " + NumberFormat.getInstance().format(this.openBuffers.fillingRatio()) + "%"); //$NON-NLS-1$//$NON-NLS-2$
}
}
public static IBuffer createBuffer(IOpenable owner) {
IJavaElement element = (IJavaElement)owner;
IResource resource = element.getResource();
return
new Buffer(
resource instanceof IFile ? (IFile)resource : null,
owner,
element.isReadOnly());
}
public static IBuffer createNullBuffer(IOpenable owner) {
IJavaElement element = (IJavaElement)owner;
IResource resource = element.getResource();
return
new NullBuffer(
resource instanceof IFile ? (IFile)resource : null,
owner,
element.isReadOnly());
}
/**
* Returns the open buffer associated with the given owner,
* or <code>null</code> if the owner does not have an open
* buffer associated with it.
*/
public IBuffer getBuffer(IOpenable owner) {
synchronized (this.openBuffers) {
return (IBuffer)this.openBuffers.get(owner);
}
}
/**
* Returns the default buffer manager.
*/
public synchronized static BufferManager getDefaultBufferManager() {
if (DEFAULT_BUFFER_MANAGER == null) {
DEFAULT_BUFFER_MANAGER = new BufferManager();
}
return DEFAULT_BUFFER_MANAGER;
}
/**
* Returns the default buffer factory.
* @deprecated
*/
public org.aspectj.org.eclipse.jdt.core.IBufferFactory getDefaultBufferFactory() {
return this.defaultBufferFactory;
}
/**
* Returns an enumeration of all open buffers.
* <p>
* The <code>Enumeration</code> answered is thread safe.
*
* @see OverflowingLRUCache
* @return Enumeration of IBuffer
*/
public Enumeration getOpenBuffers() {
Enumeration result;
synchronized (this.openBuffers) {
this.openBuffers.shrink();
result = this.openBuffers.elements();
}
// close buffers that were removed from the cache if space was needed
this.openBuffers.closeBuffers();
return result;
}
/**
* Removes a buffer from the table of open buffers.
*/
protected void removeBuffer(IBuffer buffer) {
if (VERBOSE) {
String owner = ((Openable)buffer.getOwner()).toStringWithAncestors();
System.out.println("Removing buffer for " + owner); //$NON-NLS-1$
}
synchronized (this.openBuffers) {
this.openBuffers.remove(buffer.getOwner());
}
// close buffers that were removed from the cache (should be only one)
this.openBuffers.closeBuffers();
if (VERBOSE) {
System.out.println("-> Buffer cache filling ratio = " + NumberFormat.getInstance().format(this.openBuffers.fillingRatio()) + "%"); //$NON-NLS-1$//$NON-NLS-2$
}
}
}