de.intarsys.tools.logging.MemoryLogHandler Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of isrt Show documentation
The basic runtime tools and interfaces for intarsys components.
There is a newer version: 4.11
package de.intarsys.tools.logging;

import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;

import de.intarsys.tools.event.AttributeChangedEvent;
import de.intarsys.tools.event.Event;
import de.intarsys.tools.event.EventDispatcher;
import de.intarsys.tools.event.EventType;
import de.intarsys.tools.event.INotificationListener;
import de.intarsys.tools.event.INotificationSupport;

/**
 * A {@link Handler} that keeps its {@link LogRecord}s in memory.
 * 
 */
public class MemoryLogHandler extends Handler implements INotificationSupport {

	private final static int DEFAULT_SIZE = 1000;

	final private int size;

	final private String id;

	final private LogRecord buffer[];

	private int start, count;

	private EventDispatcher dispatcher;

	public MemoryLogHandler(String id) {
		this.size = DEFAULT_SIZE;
		this.id = id;
		setFormatter(new SimpleFormatter());
		buffer = new LogRecord[size];
		start = 0;
		count = 0;
	}

	public MemoryLogHandler(String id, int size) {
		if (size <= 0) {
			throw new IllegalArgumentException();
		}
		this.size = size;
		this.id = id;
		setFormatter(new SimpleFormatter());
		buffer = new LogRecord[size];
		start = 0;
		count = 0;
	}

	synchronized public void addNotificationListener(EventType type,
			INotificationListener listener) {
		if (dispatcher == null) {
			dispatcher = new EventDispatcher(this);
		}
		dispatcher.addNotificationListener(type, listener);
	}

	public synchronized void clear() {
		for (int i = 0; i < buffer.length; i++) {
			buffer[i] = null;
		}
		start = 0;
		count = 0;
		triggerChanged(null, null, null);
	}

	@Override
	public void close() throws SecurityException {
		setLevel(Level.OFF);
	}

	@Override
	public void flush() {
	}

	public String getId() {
		return id;
	}

	synchronized public LogRecord[] getLogRecords() {
		LogRecord[] result = new LogRecord[count];
		for (int i = 0; i < count; i++) {
			int ix = (start + i) % buffer.length;
			result[i] = buffer[ix];
		}
		return result;
	}

	synchronized public int getSize() {
		return size;
	}

	public String getString() {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < count; i++) {
			int ix = (start + i) % buffer.length;
			try {
				sb.append(getFormatter().format(buffer[ix]));
			} catch (Exception ex) {
				//
			}
		}
		return sb.toString();
	}

	@Override
	public synchronized void publish(LogRecord record) {
		if (!isLoggable(record)) {
			return;
		}
		int ix = (start + count) % buffer.length;
		buffer[ix] = record;
		if (count < buffer.length) {
			count++;
		} else {
			start++;
			start %= buffer.length;
		}
		triggerChanged(null, null, record);
	}

	public synchronized void push(Handler target) {
		for (int i = 0; i < count; i++) {
			int ix = (start + i) % buffer.length;
			target.publish(buffer[ix]);
		}
		clear();
	}

	synchronized public void removeNotificationListener(EventType type,
			INotificationListener listener) {
		if (dispatcher == null) {
			return;
		}
		dispatcher.removeNotificationListener(type, listener);
		if (dispatcher.isEmpty()) {
			dispatcher = null;
		}
	}

	protected void triggerChanged(Object attribute, Object oldValue,
			Object newValue) {
		Event event = new AttributeChangedEvent(this, attribute, oldValue,
				newValue);
		triggerEvent(event);
	}

	protected void triggerEvent(Event event) {
		if (dispatcher == null) {
			return;
		}
		try {
			dispatcher.triggerEvent(event);
		} catch (RuntimeException e) {
			// ignore
		}
	}

}