| /******************************************************************************* |
| * Copyright (c) 2008 Ketan Padegaonkar 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: |
| * Ketan Padegaonkar - initial API and implementation |
| * Hans Schwaebli - http://swtbot.org/bugzilla/show_bug.cgi?id=112 |
| *******************************************************************************/ |
| package org.eclipse.swtbot.swt.finder.utils; |
| |
| import java.util.Arrays; |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| |
| /** |
| * Message formatter to optimize logging performance. The cost of logging is mostly in the string concatenation and |
| * parameter evaluation of arguments. Log4j logs the object by invoking {@link #toString()} on the object being logged. |
| * This class performs lazy evaluation of the message, only when {@link #toString()} is invoked, which happens at the |
| * time of logging. |
| * <p> |
| * <b>Note:</b> This class uses a ThreadLocal cache instead of a single cache, since the cache would then need to be |
| * synchronized since multiple threads would access it. |
| * </p> |
| * |
| * @author Ketan Padegaonkar <KetanPadegaonkar [at] gmail [dot] com> |
| * @version $Id$ |
| */ |
| public class MessageFormat { |
| |
| private final String pattern; |
| private final Object[] args; |
| private static final ThreadLocal<Map<String, java.text.MessageFormat>> threadLocal = new ThreadLocal<Map<String, java.text.MessageFormat>>() { |
| @Override |
| protected java.util.Map<String, java.text.MessageFormat> initialValue() { |
| return new LRUMap<String, java.text.MessageFormat>(); |
| }; |
| }; |
| |
| private MessageFormat(String pattern, Object... args) { |
| this.pattern = pattern; |
| this.args = args; |
| } |
| |
| public static MessageFormat format(String s, Object... args) { |
| return new MessageFormat(s, args); |
| } |
| |
| @Override |
| public String toString() { |
| try { |
| java.text.MessageFormat formatter = formatter(pattern); |
| return formatter.format(args); |
| } catch (Exception e) { |
| return "MessageFormat: Could not translate message: '" + pattern + "' using arguments " + Arrays.asList(args); //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| } |
| |
| private java.text.MessageFormat formatter(String pattern) { |
| java.text.MessageFormat formatter = threadLocal.get().get(pattern); |
| if (formatter == null) { |
| formatter = new java.text.MessageFormat(pattern); |
| threadLocal.get().put(pattern, formatter); |
| } |
| return formatter; |
| } |
| |
| private static final class LRUMap<K, V> extends LinkedHashMap<K, V> { |
| private static final int MAX_SIZE = 512; |
| |
| @Override |
| protected boolean removeEldestEntry(Entry<K, V> eldest) { |
| return size() > MAX_SIZE; |
| } |
| } |
| } |