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A framework for writing end-to-end integration tests using the Concourse client and server
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/*
 * Copyright (c) 2015 Cinchapi, Inc.
 * 
 * Licensed 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 org.cinchapi.concourse.util;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.List;

import org.cinchapi.concourse.annotate.UtilityClass;

import com.google.common.base.Throwables;
import com.google.common.collect.Lists;

/**
 * Utilities for dealing with {@link Process} objects.
 * 
 * @author jnelson
 */
@UtilityClass
public final class Processes {

    /**
     * Get the stdout for {@code process}.
     * 
     * @param process
     * @return a collection of output lines
     */
    public static List getStdOut(Process process) {
        return readStream(process.getInputStream());

    }

    /**
     * Read an input stream.
     * 
     * @param stream
     * @return the lines in the stream
     */
    private static List readStream(InputStream stream) {
        try {
            BufferedReader out = new BufferedReader(new InputStreamReader(
                    stream));
            String line;
            List output = Lists.newArrayList();
            while ((line = out.readLine()) != null) {
                output.add(line);
            }
            return output;
        }
        catch (Exception e) {
            throw Throwables.propagate(e);
        }
    }

    /**
     * Similar to {@link Process#waitFor()} but will throw a
     * {@link RuntimeException} if the process does not have an exit code of
     * {@code 0}.
     * 
     * @param process
     */
    public static void waitForSuccessfulCompletion(Process process) {
        try {
            int exitVal = process.waitFor();
            if(exitVal != 0) {
                throw new RuntimeException(getStdErr(process).toString());
            }
        }
        catch (Exception e) {
            throw Throwables.propagate(e);
        }
    }

    /**
     * Get the stderr for {@code process}.
     * 
     * @param process
     * @return a collection of error lines
     */
    public static List getStdErr(Process process) {
        return readStream(process.getErrorStream());
    }

    private Processes() {} /* noinit */

}