LoggingOutputStream.java

/**
 * LoggingOutputStream
 * 
 */
package gov.usgs.util.logging;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * An OutputStream that writes contents to a Logger upon each call to flush().
 *
 * From http://blogs.sun.com/nickstephen/entry/java_redirecting_system_out_and
 */
public class LoggingOutputStream extends ByteArrayOutputStream {

    private String lineSeparator;

    private Logger logger;
    private Level level;

    /**
     * Constructor
     * 
     * @param logger
     *            Logger to write to
     * @param level
     *            Level at which to write the log message
     */
    public LoggingOutputStream(Logger logger, Level level) {
        super();
        this.logger = logger;
        this.level = level;
        lineSeparator = System.getProperty("line.separator");
    }

    /**
     * upon flush() write the existing contents of the OutputStream to the
     * logger as a log record.
     * 
     * @throws java.io.IOException
     *             in case of error
     */
    public void flush() throws IOException {

        String record;
        synchronized (this) {
            super.flush();
            record = this.toString().trim();
            super.reset();

            if (record.length() == 0 || record.equals(lineSeparator)) {
                // avoid empty records
                return;
            }

            logger.logp(level, "", "", record);
        }
    }
}