OutputStreamPrinter.java

/**
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.commons.utils;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;

import org.gatein.common.io.UndeclaredIOException;

/**
 * <p>
 * An extension of {@link Printer} that encodes the text with a provided encoder and sends the resulting bytes on an
 * {@link java.io.OutputStream}. The instance can be configured to have different behavior on failure of the output stream.
 * </p>
 *
 * <p>
 * The <tt>ignoreOnFailure</tt> property will stop to make further invocations to the output stream if an exception is thrown by
 * the output stream except for the {@link #close()} method.
 * </p>
 *
 * <p>
 * The <tt>failureFlow</tt> property modifies the control flow of the method invocation when the output stream throws an
 * {@link java.io.IOException}.
 *
 * <ul>
 * <li>The {@link IOFailureFlow#IGNORE} value ignores the exception.</li>
 * <li>The {@link IOFailureFlow#RETHROW} value rethrows the exception.</li>
 * <li>The {@link IOFailureFlow#THROW_UNDECLARED} value throws instead a {@link UndeclaredIOException} exception wrapping the
 * original exception.</li>
 * </ul>
 *
 * </p>
 *
 * <p>
 * The class provides direct write access to the underlying output stream when the client of the stream can provides bytes
 * directly.
 * </p>
 *
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
public class OutputStreamPrinter extends Printer implements BinaryOutput {

    private final IOFailureFlow failureFlow;

    private final boolean ignoreOnFailure;

    private final OutputStream out;

    private final TextEncoder encoder;

    private boolean failed;

    private final boolean flushOnClose;

    /**
     * Builds an instance with the failureFlow being {@link IOFailureFlow#RETHROW} and a the ignoreOnFailure property set to
     * false.
     *
     * @param encoder the encoder
     * @param out the output
     * @param flushOnClose flush when stream is closed
     * @throws IllegalArgumentException if any argument is null
     */
    public OutputStreamPrinter(TextEncoder encoder, OutputStream out, boolean flushOnClose) throws IllegalArgumentException {
        this(encoder, out, IOFailureFlow.RETHROW, false, flushOnClose, 0, false);
    }

    /**
     * Builds an instance with the failureFlow being {@link IOFailureFlow#RETHROW} and a the ignoreOnFailure property set to
     * false.
     *
     * @param encoder the encoder
     * @param out the output
     * @param flushOnClose flush when stream is closed
     * @param bufferSize the size of the buffer
     * @throws IllegalArgumentException if any argument is null
     */
    public OutputStreamPrinter(TextEncoder encoder, OutputStream out, boolean flushOnClose, int bufferSize)
            throws IllegalArgumentException {
        this(encoder, out, IOFailureFlow.RETHROW, false, flushOnClose, bufferSize, false);
    }

    /**
     * Builds an instance with the failureFlow being {@link IOFailureFlow#RETHROW} and a the ignoreOnFailure property set to
     * false.
     *
     * @param encoder the encoder
     * @param out the output
     * @param flushOnClose flush when stream is closed
     * @param bufferSize the initial size of the buffer
     * @param growing if the buffer should grow in size once full
     * @throws IllegalArgumentException if any argument is null
     */
    public OutputStreamPrinter(TextEncoder encoder, OutputStream out, boolean flushOnClose, int bufferSize, boolean growing)
            throws IllegalArgumentException {
        this(encoder, out, IOFailureFlow.RETHROW, false, flushOnClose, bufferSize, growing);
    }

    /**
     * Builds an instance with the failureFlow being {@link IOFailureFlow#RETHROW} and a the ignoreOnFailure property set to
     * false.
     *
     * @param encoder the encoder
     * @param out the output
     * @throws IllegalArgumentException if any argument is null
     */
    public OutputStreamPrinter(TextEncoder encoder, OutputStream out) throws IllegalArgumentException {
        this(encoder, out, IOFailureFlow.RETHROW, false, false, 0, false);
    }

    /**
     * Builds a new instance with the specified parameters and the delegate output.
     *
     * @param encoder the encoder
     * @param out the output
     * @param failureFlow the control flow failureFlow
     * @param ignoreOnFailure the behavior on failure
     * @param flushOnClose flush when stream is closed
     * @param bufferSize the buffer size
     * @throws IllegalArgumentException if any argument is null
     */
    public OutputStreamPrinter(TextEncoder encoder, OutputStream out, IOFailureFlow failureFlow, boolean ignoreOnFailure,
            boolean flushOnClose, int bufferSize) throws IllegalArgumentException {
        this(encoder, out, failureFlow, ignoreOnFailure, flushOnClose, bufferSize, false);
    }

    public OutputStreamPrinter(TextEncoder encoder, OutputStream out, IOFailureFlow failureFlow, boolean ignoreOnFailure,
            boolean flushOnClose, int bufferSize, boolean growing) throws IllegalArgumentException {
        if (encoder == null) {
            throw new IllegalArgumentException("No null encoder accepted");
        }
        if (out == null) {
            throw new IllegalArgumentException("No null output stream accepted");
        }
        if (failureFlow == null) {
            throw new IllegalArgumentException("No null control flow mode accepted");
        }
        if (bufferSize < 0) {
            throw new IllegalArgumentException("Invalid negative max buffer size: " + bufferSize);
        }

        //
        if (bufferSize > 0 && !growing) {
            out = new BufferingOutputStream(out, bufferSize);
        } else if (growing) {
            out = new GrowingOutputStream(out, bufferSize);
        }

        //
        this.encoder = encoder;
        this.out = out;
        this.failureFlow = failureFlow;
        this.failed = false;
        this.ignoreOnFailure = ignoreOnFailure;
        this.flushOnClose = flushOnClose;
    }

    public final Charset getCharset() {
        return encoder.getCharset();
    }

    /**
     * Returns the failure flow.
     *
     * @return the failure flow
     */
    public final IOFailureFlow getFailureFlow() {
        return failureFlow;
    }

    /**
     * Returns the ignore on failure property.
     *
     * @return the ignore on failure property
     */
    public final boolean getIgnoreOnFailure() {
        return ignoreOnFailure;
    }

    public final boolean isFailed() {
        return failed;
    }

    // Bytes access interface

    public final void write(byte b) throws IOException {
        if (!failed) {
            try {
                out.write(b);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    public final void write(byte[] bytes) throws IOException {
        if (!failed) {
            try {
                out.write(bytes);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    public final void write(byte[] bytes, int off, int len) throws IOException {
        if (!failed) {
            try {
                out.write(bytes, off, len);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    //

    @Override
    // Note that the parent method has a synchronisation that we want to avoid
    // for performance reasons
    public final void write(int c) throws IOException {
        if (!failed) {
            try {
                encoder.encode((char) c, out);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    @Override
    public final void write(char[] cbuf) throws IOException {
        if (!failed) {
            try {
                encoder.encode(cbuf, 0, cbuf.length, out);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    @Override
    public final void write(String str) throws IOException {
        if (!failed) {
            try {
                encoder.encode(str, 0, str.length(), out);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    @Override
    // Note that the parent method has a synchronisation that we want to avoid
    // for performance reasons
    public final void write(String str, int off, int len) throws IOException {
        if (!failed) {
            try {
                encoder.encode(str, off, len, out);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    public final void write(char[] cbuf, int off, int len) throws IOException {
        if (!failed) {
            try {
                encoder.encode(cbuf, off, len, out);
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    public final void flush() throws IOException {
        if (!failed && !flushOnClose) {
            try {
                out.flush();
            } catch (IOException e) {
                handle(e);
            }
        }
    }

    public final void close() throws IOException {
        try {
            out.close();
        } catch (IOException e) {
            handle(e);
        }
    }

    private void handle(IOException e) throws IOException {
        if (ignoreOnFailure) {
            failed = true;
        }
        switch (failureFlow) {
            case IGNORE:
                break;
            case THROW_UNDECLARED:
                throw new UndeclaredIOException(e);
            case RETHROW:
                throw e;
        }
    }

    /**
     * Flush the output stream. This allows for the outputstream to be independently flushed regardless of the flushOnClose
     * setting.
     */
    public void flushOutputStream() throws IOException {
        if (!failed) {
            try {
                out.flush();
            } catch (IOException e) {
                handle(e);
            }
        }
    }
}