bundles/org.eclipse.equinox.log.stream/osgi/src/org/osgi/service/log/stream/LogStreamProvider.java

/*
 * Copyright (c) OSGi Alliance (2016). All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.osgi.service.log.stream;

import org.osgi.annotation.versioning.ProviderType;
import org.osgi.service.log.LogEntry;
import org.osgi.util.pushstream.PushStream;

/**
 * LogStreamProvider service for creating a PushStream of {@link LogEntry}
 * objects.
 * 
 * @ThreadSafe
 * @author $Id$
 */
@ProviderType
public interface LogStreamProvider {
	/**
	 * Creation options for the PushStream of {@link LogEntry} objects.
	 */
	enum Options {
		/**
		 * Include history.
		 * <p>
		 * Prime the created PushStream with the past {@link LogEntry} objects.
		 * The number of past {@link LogEntry} objects is implementation
		 * specific.
		 * <p>
		 * The created PushStream will supply the past {@link LogEntry} objects
		 * followed by newly created {@link LogEntry} objects.
		 */
		HISTORY;
	}

	/**
	 * Create a PushStream of {@link LogEntry} objects.
	 * <p>
	 * The returned PushStream is an unbuffered stream with a parallelism of
	 * one.
	 * <p>
	 * When this LogStreamProvider service is released by the obtaining bundle,
	 * this LogStreamProvider service must call {@code close()} on the returned
	 * PushStream object if it has not already been closed.
	 * 
	 * @param options The options to use when creating the PushStream.
	 * @return A PushStream of {@link LogEntry} objects.
	 */
	PushStream<LogEntry> createStream(Options... options);
}