uk.co.unclealex.process.builder.BuildingProcessRequest.java Source code

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/**
 * Copyright 2012 Alex Jones
 *
 * 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.    
 *
 */
package uk.co.unclealex.process.builder;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.Reader;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;

import org.apache.commons.io.IOUtils;

import uk.co.unclealex.process.BuildableProcessRequest;
import uk.co.unclealex.process.EchoingProcessCallback;
import uk.co.unclealex.process.ProcessCallback;
import uk.co.unclealex.process.ProcessFailedException;
import uk.co.unclealex.process.ProcessResult;
import uk.co.unclealex.process.stream.StandardInputSupplier;

import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;

/**
 * An implementation of {@link BuildableProcessRequest}.
 * 
 * @author alex
 * 
 */
abstract class BuildingProcessRequest extends BasicProcessRequest implements BuildableProcessRequest {

    /**
     * The arguments to the command.
     */
    private final List<String> arguments = Lists.newArrayList();

    /**
     * The class to use to supply information to standard input.
     */
    private StandardInputSupplier standardInputSupplier;

    /**
     * The {@link ProcessCallback}s to use to monitor command execution.
     */
    private final List<ProcessCallback> processCallbacks = Lists.newArrayList();

    /**
     * Instantiates a new building process request.
     * 
     * @param executor
     *          the executor
     */
    public BuildingProcessRequest(final ExecutorService executor) {
        super(executor);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withArguments(final String... arguments) {
        getArguments().addAll(Arrays.asList(arguments));
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withArguments(final Iterable<String> arguments) {
        Iterables.addAll(getArguments(), arguments);
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withCallbacks(final ProcessCallback... processCallbacks) {
        getProcessCallbacks().addAll(Arrays.asList(processCallbacks));
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withCallbacks(final Iterable<ProcessCallback> processCallbacks) {
        Iterables.addAll(getProcessCallbacks(), processCallbacks);
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withStandardInput(final InputStream standardInput) {
        final StandardInputSupplier copier = new StandardInputCopier() {

            @Override
            public void copyToStandardInput(final OutputStream standardInputOutputStream) throws IOException {
                IOUtils.copy(standardInput, standardInputOutputStream);
            }
        };
        return withStandardInputSupplier(copier);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withStandardInput(final Reader reader, final String charset) {
        final StandardInputSupplier copier = new StandardInputCopier() {
            @Override
            public void copyToStandardInput(final OutputStream standardInputOutputStream) throws IOException {
                IOUtils.copy(reader, standardInputOutputStream, charset);
            }
        };
        return withStandardInputSupplier(copier);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withStandardInput(final Reader reader) {
        final StandardInputSupplier copier = new StandardInputCopier() {
            @Override
            public void copyToStandardInput(final OutputStream standardInputOutputStream) throws IOException {
                IOUtils.copy(reader, standardInputOutputStream, Charset.defaultCharset().name());
            }
        };
        return withStandardInputSupplier(copier);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withStandardInputSupplier(final StandardInputSupplier standardInputSupplier) {
        setStandardInputSupplier(standardInputSupplier);
        if (standardInputSupplier instanceof ProcessCallback) {
            return withCallbacks((ProcessCallback) standardInputSupplier);
        } else {
            return this;
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withStandardOutput(final PrintStream stdout) {
        return withCallbacks(new EchoingProcessCallback(stdout, null));
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public BuildableProcessRequest withStandardError(final PrintStream stderr) {
        return withCallbacks(new EchoingProcessCallback(null, stderr));
    }

    /**
     * Create the command file required to run this command, if neccessary.
     * 
     * @return The string required to call this command or file.
     * @throws IOException
     *           Signals that an I/O exception has occurred.
     */
    protected abstract String createCommand() throws IOException;

    /**
     * {@inheritDoc}
     */
    @Override
    public ProcessResult executeAndWait() throws IOException {
        return executeAndWait(true);
    }

    @Override
    public ProcessResult executeAndWait(final boolean throwOnNonZeroReturn) throws IOException {
        try {
            final ProcessResult processResult = createExecutable().call();
            if (processResult.getReturnValue() != 0) {
                throw new ProcessFailedException("A process returned code " + processResult.getReturnValue(),
                        processResult);
            }
            return processResult;
        } catch (final Exception e) {
            if (e instanceof IOException) {
                throw (IOException) e;
            } else {
                throw new IOException(e);
            }
        }
    }

    /**
     * {@inheritDoc}
     * 
     * @throws IOException
     */
    @Override
    public Future<ProcessResult> execute() throws IOException {
        return getExecutor().submit(createExecutable());
    }

    /**
     * Create a {@link Callable} that creates the command and executes it.
     * 
     * @return A {@link Callable} that creates the command and executes it.
     * @throws IOException
     */
    protected Callable<ProcessResult> createExecutable() throws IOException {
        final String command = createCommand();
        final Callable<ProcessResult> task = execute(command, getProcessCallbacks(), getArguments(),
                getStandardInputSupplier());
        final Callable<ProcessResult> callable = new Callable<ProcessResult>() {
            @Override
            public ProcessResult call() throws Exception {
                try {
                    return task.call();
                } finally {
                    destroyCommand();
                }
            }
        };
        return callable;
    }

    /**
     * Destroy any remnants created by the {@link #createCommand()} methods.
     */
    protected abstract void destroyCommand();

    /**
     * Gets the arguments to the command.
     * 
     * @return the arguments
     */
    protected List<String> getArguments() {
        return arguments;
    }

    /**
     * Gets the {@link ProcessCallback}s to use to monitor command execution.
     * 
     * @return the processCallbacks
     */
    protected List<ProcessCallback> getProcessCallbacks() {
        return processCallbacks;
    }

    protected StandardInputSupplier getStandardInputSupplier() {
        return standardInputSupplier;
    }

    protected void setStandardInputSupplier(final StandardInputSupplier standardInputSupplier) {
        this.standardInputSupplier = standardInputSupplier;
    }

}