plugins/org.eclipse.app4mc.util.sessionlog/src/org/eclipse/app4mc/util/sessionlog/SessionLogger.java

/**
 ********************************************************************************
 * Copyright (c) 2021 Robert Bosch GmbH and others.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Robert Bosch GmbH - initial API and implementation
 ********************************************************************************
 */
package org.eclipse.app4mc.util.sessionlog;

import java.io.File;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.concurrent.CopyOnWriteArrayList;

import org.eclipse.app4mc.util.sessionlog.SessionLogEntry.Status;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.annotations.ReferenceCardinality;
import org.osgi.service.component.annotations.ReferencePolicy;
import org.osgi.service.component.annotations.ReferencePolicyOption;

/**
 * Service factory to create a service that can be used to collect session log
 * statements, e.g. for a migration or a transformation session. The collected
 * log statements can then be flushed via SessionLogWriter services, e.g. to a
 * file or to the console.
 */
@Component(factory = "org.eclipse.app4mc.amalthea.sessionlog.factory", service = SessionLogger.class)
public class SessionLogger {

	CopyOnWriteArrayList<SessionLogWriter> logWriter = new CopyOnWriteArrayList<>();
	
	ArrayList<SessionLogEntry> log = new ArrayList<>();
	
	public void error(String msg, Object... args) {
		String message = (args != null && args.length > 0) ? MessageFormat.format(msg, args) : msg;
		Exception e = null;
		if (args != null && args.length > 0 && args[args.length - 1] instanceof Exception) {
			e = (Exception) args[args.length - 1];
		}
		this.log.add(new SessionLogEntry(Status.ERROR, "ERROR: " + message, e));
	}
	
	public void warn(String msg, Object... args) {
		String message = (args != null && args.length > 0) ? MessageFormat.format(msg, args) : msg;
		this.log.add(new SessionLogEntry(Status.WARNING, "WARN : " + message));
	}
	
	public void info(String msg, Object... args) {
		String message = (args != null && args.length > 0) ? MessageFormat.format(msg, args) : msg;
		this.log.add(new SessionLogEntry(Status.INFO, "INFO : " + message));
	}
	
	public void flush(File sessionLogFile) {
		this.logWriter.forEach(w -> w.write(sessionLogFile, new ArrayList<>(this.log)));
		this.log.clear();
	}
	
	@Reference(cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC, policyOption = ReferencePolicyOption.GREEDY)
	public void registerLogWriter(SessionLogWriter writer) {
		this.logWriter.add(writer);
	}
	
	public void unregisterLogWriter(SessionLogWriter writer) {
		this.logWriter.remove(writer);
	}
}