org.codehaus.plexus.util.cli.StreamFeeder Maven / Gradle / Ivy

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package org.codehaus.plexus.util.cli;

/*
 * Copyright The Codehaus Foundation.
 *
 * 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.
 */

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Read from an InputStream and write the output to an OutputStream.
 *
 * @author Trygve Laugstøl
 *
 */
public class StreamFeeder extends AbstractStreamHandler {

    private InputStream input;

    private OutputStream output;

    private volatile Throwable exception = null;

    /**
     * Create a new StreamFeeder
     *
     * @param input Stream to read from
     * @param output Stream to write to
     */
    public StreamFeeder(InputStream input, OutputStream output) {
        super();
        this.input = input;
        this.output = output;
    }

    @Override
    public void run() {
        try {
            feed();
        } catch (Throwable ex) {
            if (exception == null) {
                exception = ex;
            }
        } finally {
            close();

            synchronized (this) {
                setDone();

                this.notifyAll();
            }
        }
    }

    public void close() {
        if (input != null) {
            synchronized (input) {
                try {
                    input.close();
                } catch (IOException ex) {
                    if (exception == null) {
                        exception = ex;
                    }
                }

                input = null;
            }
        }

        if (output != null) {
            synchronized (output) {
                try {
                    output.close();
                } catch (IOException ex) {
                    if (exception == null) {
                        exception = ex;
                    }
                }

                output = null;
            }
        }
    }

    /**
     * @since 3.1.0
     * @return the Exception
     */
    public Throwable getException() {
        return exception;
    }

    private void feed() throws IOException {
        boolean flush = false;
        int data = input.read();

        while (!isDone() && data != -1) {
            synchronized (output) {
                if (!isDisabled()) {
                    output.write(data);
                    flush = true;
                }

                data = input.read();
            }
        }

        if (flush) {
            output.flush();
        }
    }
}