maven-surefire-common/src/main/java/org/apache/maven/plugin/surefire/booterclient/lazytestprovider/OutputStreamFlushableCommandline.java

package org.apache.maven.plugin.surefire.booterclient.lazytestprovider;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.ConcurrentLinkedDeque;

import org.apache.maven.surefire.shared.utils.cli.CommandLineException;
import org.apache.maven.surefire.shared.utils.cli.CommandLineUtils;
import org.apache.maven.surefire.shared.utils.cli.Commandline;

/**
 * A {@link Commandline} implementation that provides the output stream of
 * the executed process in form of a {@link FlushReceiver}, for it to be
 * flushed on demand.
 *
 * @author Andreas Gudian
 */
public class OutputStreamFlushableCommandline
    extends Commandline
    implements FlushReceiverProvider
{
    private final Collection<String> excludedEnvironmentVariables;
    private final Set<String> addedEnvironmentVariables;
    private volatile FlushReceiver flushReceiver;

    /**
     * for testing purposes only
     */
    public OutputStreamFlushableCommandline()
    {
        this( new String[0] );
    }

    public OutputStreamFlushableCommandline( String[] excludedEnvironmentVariables )
    {
        this.excludedEnvironmentVariables = new ConcurrentLinkedDeque<>();
        addedEnvironmentVariables = new HashSet<>();
        Collections.addAll( this.excludedEnvironmentVariables, excludedEnvironmentVariables );
    }

    @Override
    public void addEnvironment( String name, String value )
    {
        super.addEnvironment( name, value );
        addedEnvironmentVariables.add( name );
    }

    @Override
    public final void addSystemEnvironment()
    {
        Properties systemEnvVars = CommandLineUtils.getSystemEnvVars();

        for ( String key : systemEnvVars.stringPropertyNames() )
        {
            if ( !addedEnvironmentVariables.contains( key ) && !excludedEnvironmentVariables.contains( key ) )
            {
                addEnvironment( key, systemEnvVars.getProperty( key ) );
            }
        }
    }

    @Override
    public Process execute()
        throws CommandLineException
    {
        Process process = super.execute();

        if ( process.getOutputStream() != null )
        {
            flushReceiver = new OutputStreamFlushReceiver( process.getOutputStream() );
        }

        return process;
    }

    @Override
    public FlushReceiver getFlushReceiver()
    {
        return flushReceiver;
    }
}