# FileOutput.java

    /*******************************************************************************
     * Copyright (c) 2009, 2013 Mountainminds GmbH & Co. KG and Contributors
     * 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:
     *    Brock Janiczak - initial API and implementation
     *
     *******************************************************************************/
    package org.jacoco.agent.rt.internal.output;

    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;

    import org.jacoco.core.data.ExecutionDataWriter;
    import org.jacoco.core.runtime.AgentOptions;
    import org.jacoco.core.runtime.RuntimeData;

    /**
     * Local only agent output that will write coverage data to the filesystem. This
     * controller uses the following agent options:
     * <ul>
     * <li>destfile</li>
     * <li>append</li>
     * </ul>
     */
    public class FileOutput implements IAgentOutput {

    	private RuntimeData data;

    	private File destFile;

    	private boolean append;

    	public final void startup(final AgentOptions options, final RuntimeData data)
    			throws IOException {
    		this.data = data;
    		this.destFile = new File(options.getDestfile()).getAbsoluteFile();
    		this.append = options.getAppend();
    		final File folder = destFile.getParentFile();
    		if (folder != null) {
    			folder.mkdirs();
    		}
    		// Make sure we can write to the file:
    		openFile().close();
    	}

    	public void writeExecutionData(final boolean reset) throws IOException {
    		final OutputStream output = openFile();
    		try {
    			final ExecutionDataWriter writer = new ExecutionDataWriter(output);
    			data.collect(writer, writer, reset);
    		} finally {
    			output.close();
    		}
    	}

    	public void shutdown() throws IOException {
    		// Nothing to do
    	}

    	private OutputStream openFile() throws IOException {
    		final FileOutputStream file = new FileOutputStream(destFile, append);
    		// Avoid concurrent writes from different agents running in parallel:
    		file.getChannel().lock();
    		return file;
    	}

    }