com.github.jlgrock.javascriptframework.mavenutils.logging.Log4jOutputStream Maven / Gradle / Ivy

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Although this is technically not a plugin, this is a bunch of tools that all of the plugins use. This is very useful for anyone doing maven plugin development.

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package com.github.jlgrock.javascriptframework.mavenutils.logging;

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

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/**
 * An output stream that ports output to log4j. Especially useful when porting
 * System.err and System.out streams.
 * 
 */
public class Log4jOutputStream extends OutputStream {
	/**
	 * The character used as the line separator constant.
	 */
	private static final String LINE_SEPERATOR = System
			.getProperty("line.separator");

	/**
	 * The boolean to keep track if the output stream has been closed.
	 */
	private boolean isClosed = false;

	/**
	 * The internal buffer where data is stored.
	 */
	private byte[] buffer;

	/**
	 * The number of bytes in the buffer.
	 */
	private int count;

	/**
	 * The initial number of bytes in the buffer.
	 */
	private static final int DEFAULT_BUFFER_LENGTH = 1024;

	/**
	 * The logger to log to.
	 */
	private final Logger logger;

	/**
	 * The level to use when writing to the logger.
	 */
	private final Level level;

	/**
	 * Constructor.
	 * 
	 * @param loggerIn
	 *            the logger to log output to
	 * @param levelIn
	 *            the level at which to log messages at
	 */
	public Log4jOutputStream(final Logger loggerIn, final Level levelIn) {
		if (loggerIn == null || levelIn == null) {
			throw new IllegalArgumentException(
					"nether logger nor level are allowed to be null");
		}
		logger = loggerIn;
		level = levelIn;
		count = 0;
		buffer = new byte[DEFAULT_BUFFER_LENGTH];
	}

	@Override
	public final void close() {
		flush();
		isClosed = true;
	}

	@Override
	public final void write(final int b) throws IOException {
		if (isClosed) {
			throw new IOException("The stream has been closed.");
		}

		if (b == 0) {
			return;
		}

		if (count == buffer.length) {
			final int newBufLength = buffer.length + DEFAULT_BUFFER_LENGTH;
			final byte[] newBuf = new byte[newBufLength];
			System.arraycopy(buffer, 0, newBuf, 0, buffer.length);
			buffer = newBuf;
		}

		buffer[count] = (byte) b;
		count++;
	}

	@Override
	public final void flush() {
		if (count == 0) {
			return;
		}

		if (count == LINE_SEPERATOR.length()) {
			if (((char) buffer[0]) == LINE_SEPERATOR.charAt(0)
					&& ((count == 1) || ((count == 2) && ((char) buffer[1]) == LINE_SEPERATOR
							.charAt(1)))) {
				count = 0;
				return;
			}
		}

		final byte[] theBytes = new byte[count];
		System.arraycopy(buffer, 0, theBytes, 0, count);
		logger.log(level, new String(theBytes));
		count = 0;
	}
}