| /******************************************************************************* |
| * Copyright (c) 2009, 2010 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.osgi.service.debug; |
| |
| import java.util.EventListener; |
| |
| /** |
| * A debug options listener is notified whenever one of its plug-in option-path entries is |
| * changed. A listener is registered as an OSGi service using the {@link DebugOptions#LISTENER_SYMBOLICNAME} |
| * service property to specify the symbolic name of the debug options listener. |
| * <p> |
| * The {@link DebugOptionsListener#optionsChanged(DebugOptions)} method will automatically |
| * be called upon registration of the debug options listener service. This allows the |
| * listener to obtain the initial debug options. This initial call to the listener |
| * will happen even if debug is not enabled at the time of registration |
| * ({@link DebugOptions#isDebugEnabled()} will return false in this case). |
| * </p> |
| * A debug options listener allows a bundle to cache trace option values in boolean fields for performance |
| * and code cleanliness. For example: |
| * <pre> |
| * public class Activator implements BundleActivator, DebugOptionsListener { |
| * public static boolean DEBUG = false; |
| * public static DebugTrace trace; |
| * |
| * public void start(BundleContext context) { |
| * Hashtable props = new Hashtable(4); |
| * props.put(DebugOptions.LISTENER_SYMBOLICNAME, "com.mycompany.mybundle"); |
| * context.registerService(DebugOptionsListener.class.getName(), this, props); |
| * } |
| * |
| * public void optionsChanged(DebugOptions options) { |
| * if (trace == null) |
| * trace = options.newDebugTrace("com.mycompany.mybundle"); |
| * DEBUG = options.getBooleanOption("com.mycompany.mybundle/debug", false); |
| * } |
| * |
| * public void doSomeWork() { |
| * if (DEBUG) |
| * trace.trace(null, "Doing some work"); |
| * } |
| * ... |
| * } |
| * </pre> |
| * @since 3.5 |
| */ |
| public interface DebugOptionsListener extends EventListener { |
| |
| /** |
| * Notifies this listener that an option-path for its plug-in has changed. |
| * This method is also called initially by the DebugOptions implementation |
| * when the listener is registered as a service. This allows the listener |
| * to obtain the initial set of debug options without the need to |
| * acquire the debug options service. |
| * @param options a reference to the DebugOptions |
| */ |
| public void optionsChanged(DebugOptions options); |
| } |