| /* |
| * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package javax.swing.text; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * SegmentCache caches <code>Segment</code>s to avoid continually creating |
| * and destroying of <code>Segment</code>s. A common use of this class would |
| * be: |
| * <pre> |
| * Segment segment = segmentCache.getSegment(); |
| * // do something with segment |
| * ... |
| * segmentCache.releaseSegment(segment); |
| * </pre> |
| * |
| */ |
| class SegmentCache { |
| /** |
| * A global cache. |
| */ |
| private static SegmentCache sharedCache = new SegmentCache(); |
| |
| /** |
| * A list of the currently unused Segments. |
| */ |
| private List<Segment> segments; |
| |
| |
| /** |
| * Returns the shared SegmentCache. |
| */ |
| public static SegmentCache getSharedInstance() { |
| return sharedCache; |
| } |
| |
| /** |
| * A convenience method to get a Segment from the shared |
| * <code>SegmentCache</code>. |
| */ |
| public static Segment getSharedSegment() { |
| return getSharedInstance().getSegment(); |
| } |
| |
| /** |
| * A convenience method to release a Segment to the shared |
| * <code>SegmentCache</code>. |
| */ |
| public static void releaseSharedSegment(Segment segment) { |
| getSharedInstance().releaseSegment(segment); |
| } |
| |
| |
| |
| /** |
| * Creates and returns a SegmentCache. |
| */ |
| public SegmentCache() { |
| segments = new ArrayList<Segment>(11); |
| } |
| |
| /** |
| * Returns a <code>Segment</code>. When done, the <code>Segment</code> |
| * should be recycled by invoking <code>releaseSegment</code>. |
| */ |
| public Segment getSegment() { |
| synchronized(this) { |
| int size = segments.size(); |
| |
| if (size > 0) { |
| return segments.remove(size - 1); |
| } |
| } |
| return new CachedSegment(); |
| } |
| |
| /** |
| * Releases a Segment. You should not use a Segment after you release it, |
| * and you should NEVER release the same Segment more than once, eg: |
| * <pre> |
| * segmentCache.releaseSegment(segment); |
| * segmentCache.releaseSegment(segment); |
| * </pre> |
| * Will likely result in very bad things happening! |
| */ |
| public void releaseSegment(Segment segment) { |
| if (segment instanceof CachedSegment) { |
| synchronized(this) { |
| segment.array = null; |
| segment.count = 0; |
| segments.add(segment); |
| } |
| } |
| } |
| |
| |
| /** |
| * CachedSegment is used as a tagging interface to determine if |
| * a Segment can successfully be shared. |
| */ |
| private static class CachedSegment extends Segment { |
| } |
| } |