CapturingJULHandler.java

package org.eclipse.jetty.util.log;

import static org.hamcrest.Matchers.containsString;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.logging.Handler;
import java.util.logging.LogRecord;

import org.eclipse.jetty.util.IO;
import org.junit.Assert;

public class CapturingJULHandler extends Handler
{
    private static final String LN = System.getProperty("line.separator");
    private StringBuilder output = new StringBuilder();

    @Override
    public void publish(LogRecord record)
    {
        StringBuilder buf = new StringBuilder();
        buf.append(record.getLevel().getName()).append("|");
        buf.append(record.getLoggerName()).append("|");
        buf.append(record.getMessage());

        output.append(buf);
        if (record.getMessage().length() > 0)
        {
            output.append(LN);
        }

        if (record.getThrown() != null)
        {
            StringWriter sw = new StringWriter(128);
            PrintWriter capture = new PrintWriter(sw);
            record.getThrown().printStackTrace(capture);
            capture.flush();
            output.append(sw.toString());
            IO.close(capture);
        }
    }

    public void clear()
    {
        output.setLength(0);
    }

    @Override
    public void flush()
    {
        /* do nothing */
    }

    @Override
    public void close() throws SecurityException
    {
        /* do nothing */
    }

    public void dump()
    {
        System.out.println(output);
    }

    public void assertContainsLine(String line)
    {
        Assert.assertThat(output.toString(),containsString(line));
    }
}