org.obm.push.mail.greenmail.ExternalProcess.java Source code

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Here is the source code for org.obm.push.mail.greenmail.ExternalProcess.java

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/* ***** BEGIN LICENSE BLOCK *****
 * 
 * Copyright (C) 2011-2014  Linagora
 *
 * This program is free software: you can redistribute it and/or 
 * modify it under the terms of the GNU Affero General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version, provided you comply 
 * with the Additional Terms applicable for OBM connector by Linagora 
 * pursuant to Section 7 of the GNU Affero General Public License, 
 * subsections (b), (c), and (e), pursuant to which you must notably (i) retain 
 * the Message sent thanks to OBM, Free Communication by Linagora? 
 * signature notice appended to any and all outbound messages 
 * (notably e-mail and meeting requests), (ii) retain all hypertext links between 
 * OBM and obm.org, as well as between Linagora and linagora.com, and (iii) refrain 
 * from infringing Linagora intellectual property rights over its trademarks 
 * and commercial brands. Other Additional Terms apply, 
 * see <http://www.linagora.com/licenses/> for more details. 
 *
 * This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License 
 * for more details. 
 *
 * You should have received a copy of the GNU Affero General Public License 
 * and its applicable Additional Terms for OBM along with this program. If not, 
 * see <http://www.gnu.org/licenses/> for the GNU Affero General Public License version 3 
 * and <http://www.linagora.com/licenses/> for the Additional Terms applicable to 
 * OBM connectors. 
 * 
 * ***** END LICENSE BLOCK ***** */
package org.obm.push.mail.greenmail;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecuteResultHandler;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteWatchdog;
import org.apache.commons.exec.Executor;
import org.apache.commons.exec.PumpStreamHandler;

import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.Maps;

public abstract class ExternalProcess {

    private final CommandLine cli;
    private final Map<String, String> environment;
    private final PumpStreamHandler streamHandler;
    private final ByteArrayOutputStream processOutputStream;

    private long processTimeout;
    private long processStartTimeNeeded;

    public ExternalProcess(String executablePath, long processTimeout) {
        this(executablePath, processTimeout, 0);
    }

    public ExternalProcess(String executablePath, long processTimeout, long processStartTimeNeeded) {
        Preconditions.checkNotNull(Strings.emptyToNull(executablePath));
        Preconditions.checkArgument(processTimeout > 0);

        this.cli = new CommandLine(executablePath);
        this.environment = Maps.newHashMap();
        this.processTimeout = processTimeout;
        this.processStartTimeNeeded = processStartTimeNeeded;
        this.processOutputStream = new ByteArrayOutputStream();
        this.streamHandler = new PumpStreamHandler(processOutputStream, System.err);
    }

    protected ClosableProcess execute(Map<String, String> cliArgs) throws ExternalProcessException {
        setCommandLineArgs(cliArgs);
        final DefaultExecuteResultHandler resultHandler = new DefaultExecuteResultHandler();
        final Executor executor = buildExecutor();
        executeProcess(resultHandler, executor);
        waitForProcessStartTime(resultHandler);

        return new ClosableProcess() {
            @Override
            public void closeProcess() throws InterruptedException {
                executor.getWatchdog().destroyProcess();
                resultHandler.waitFor();
            }
        };
    }

    private Executor buildExecutor() {
        Executor executor = new DefaultExecutor();
        executor.setStreamHandler(streamHandler);
        setTimeoutWatchdog(executor);
        return executor;
    }

    private void setTimeoutWatchdog(Executor executor) {
        executor.setWatchdog(new ExecuteWatchdog(processTimeout));
    }

    private void executeProcess(DefaultExecuteResultHandler resultHandler, Executor executor)
            throws ExternalProcessException {
        try {
            executor.execute(cli, environment, resultHandler);
        } catch (IOException e) {
            throw new ExternalProcessException("Could not execute process", e);
        }
    }

    private void waitForProcessStartTime(DefaultExecuteResultHandler resultHandler)
            throws ExternalProcessException {
        try {
            if (processStartTimeNeeded > 0) {
                resultHandler.waitFor(processStartTimeNeeded);
            }
        } catch (InterruptedException e) {
            throw new ExternalProcessException("Could not execute process", e);
        }
    }

    protected Reader readProcessOutput() {
        ByteArrayInputStream processInputStream = new ByteArrayInputStream(processOutputStream.toByteArray());
        return new InputStreamReader(processInputStream, Charsets.UTF_8);
    }

    protected void addEnvironmentVariable(String key, String value) {
        environment.put(key, value);
    }

    protected void addSimpleCliArgument(String simpleArg) {
        cli.addArgument(simpleArg);
    }

    protected void addTaggedCliArgument(String name, String value) {
        cli.addArgument(name.concat(value));
    }

    public void setCommandLineArgs(Map<String, String> cliArgs) {
        for (Entry<String, String> arg : cliArgs.entrySet()) {
            addTaggedCliArgument(arg.getKey(), arg.getValue());
        }
    }

    protected String readStringProcessOutputArgument(String processOutputLine, String argTag) {
        return processOutputLine.substring(argTag.length());
    }

    protected int readIntegerProcessOutputArgument(String processOutputLine, String argTag) {
        return Integer.valueOf(readStringProcessOutputArgument(processOutputLine, argTag));
    }

    public PumpStreamHandler getStreamHandler() {
        return streamHandler;
    }

    public long getProcessStartTimeNeeded() {
        return processStartTimeNeeded;
    }
}