org.openedit.util.StreamGobbler.java Source code

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Here is the source code for org.openedit.util.StreamGobbler.java

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/*
 * Copyright 2013 John Leacox
 *
 * 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.openedit.util;

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.openedit.util.ExecutorManager;

/**
 * An object that consumes an {@link InputStream} on a daemon thread to prevent
 * the stream from blocking.
 * 
 * <p>
 * The stream can optionally be output to a logger at an INFO level. The gobbler
 * thread will run until the stream is empty or until this {@code StreamGobbler}
 * is closed.
 * 
 * @author John Leacox
 * 
 */
public class StreamGobbler implements Closeable, Runnable {
    private static final Log log = LogFactory.getLog(StreamGobbler.class);

    protected ExecutorManager fieldExecutorManager;
    private final InputStream inputStream;
    private final boolean isLoggingEnabled;
    protected Thread parentThread = null;
    protected String fieldOutput = null;
    protected boolean fieldErrorStream;

    public boolean isErrorStream() {
        return fieldErrorStream;
    }

    public void setErrorStream(boolean inIsErrorStream) {
        fieldErrorStream = inIsErrorStream;
    }

    public StreamGobbler(InputStream inputStream, boolean enableLogging) {
        this.inputStream = inputStream;
        this.isLoggingEnabled = enableLogging;

        //setName("StreamGobbler");
        //setDaemon(true);
    }

    public ExecutorManager getExecutorManager() {
        return fieldExecutorManager;
    }

    public void setExecutorManager(ExecutorManager inExecutorManager) {
        fieldExecutorManager = inExecutorManager;
    }

    /**
     * Starts gobbling the input stream.
     */
    public void gobble() {
        getExecutorManager().execute(this);
    }

    @Override
    public void run() {
        parentThread = Thread.currentThread();
        BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
        String line = null;
        try {
            StringBuffer writer = null;
            if (isLoggingEnabled) {
                writer = new StringBuffer();
            }
            while (!Thread.currentThread().isInterrupted() && (line = br.readLine()) != null) {
                if (isLoggingEnabled) {
                    writer.append(line);
                    writer.append('\n');
                    if (writer.length() > 100000) //Dont let this buffer get more than 100k of memory
                    {
                        String cut = writer.substring(writer.length() - 70000, writer.length());
                        writer = new StringBuffer(cut);
                    }
                }
            }
            if (isLoggingEnabled) {
                fieldOutput = writer.toString();
            }
        } catch (IOException e) {
            if (isLoggingEnabled) {
                log.debug("Failed to gobble stream", e);
                log.info("Failed to gobble stream");

            }
        }
    }

    public String getOutput() {
        return fieldOutput;
    }

    @Override
    public void close() throws IOException {
        if (parentThread != null) {
            parentThread.interrupt();
            //Do we need to destry this thread?

        }
        inputStream.close();
    }
}