slf4j-ext/src/main/java/org/slf4j/ext/EventData.java

/**
 * Copyright (c) 2004-2011 QOS.ch
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
package org.slf4j.ext;

import java.io.Serializable;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.beans.XMLDecoder;
import java.beans.XMLEncoder;
import java.beans.ExceptionListener;

/**
 * Base class for Event Data. Event Data contains data to be logged about an
 * event. Users may extend this class for each EventType they want to log.
 * 
 * @author Ralph Goers
 */
public class EventData implements Serializable {

    private static final long serialVersionUID = 153270778642103985L;

    private Map<String, Object> eventData = new HashMap<String, Object>();
    public static final String EVENT_MESSAGE = "EventMessage";
    public static final String EVENT_TYPE = "EventType";
    public static final String EVENT_DATETIME = "EventDateTime";
    public static final String EVENT_ID = "EventId";

    /**
     * Default Constructor
     */
    public EventData() {
    }

    /**
     * Constructor to create event data from a Map.
     * 
     * @param map
     *          The event data.
     */
    public EventData(Map<String, Object> map) {
        eventData.putAll(map);
    }

    /**
     * Construct from a serialized form of the Map containing the RequestInfo
     * elements
     * 
     * @param xml
     *          The serialized form of the RequestInfo Map.
     */
    @SuppressWarnings("unchecked")
    public EventData(String xml) {
        ByteArrayInputStream bais = new ByteArrayInputStream(xml.getBytes());
        try {
            XMLDecoder decoder = new XMLDecoder(bais);
            this.eventData = (Map<String, Object>) decoder.readObject();
        } catch (Exception e) {
            throw new EventException("Error decoding " + xml, e);
        }
    }

    /**
     * Serialize all the EventData items into an XML representation.
     * 
     * @return an XML String containing all the EventDAta items.
     */
    public String toXML() {
        return toXML(eventData);
    }

    /**
     * Serialize all the EventData items into an XML representation.
     * 
     * @param map the Map to transform
     * @return an XML String containing all the EventDAta items.
     */
    public static String toXML(Map<String, Object> map) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            XMLEncoder encoder = new XMLEncoder(baos);
            encoder.setExceptionListener(new ExceptionListener() {
                public void exceptionThrown(Exception exception) {
                    exception.printStackTrace();
                }
            });
            encoder.writeObject(map);
            encoder.close();
            return baos.toString();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * Retrieve the event identifier.
     * 
     * @return The event identifier
     */
    public String getEventId() {
        return (String) this.eventData.get(EVENT_ID);
    }

    /**
     * Set the event identifier.
     * 
     * @param eventId
     *          The event identifier.
     */
    public void setEventId(String eventId) {
        if (eventId == null) {
            throw new IllegalArgumentException("eventId cannot be null");
        }
        this.eventData.put(EVENT_ID, eventId);
    }

    /**
     * Retrieve the message text associated with this event, if any.
     * 
     * @return The message text associated with this event or null if there is
     *         none.
     */
    public String getMessage() {
        return (String) this.eventData.get(EVENT_MESSAGE);
    }

    /**
     * Set the message text associated with this event.
     * 
     * @param message
     *          The message text.
     */
    public void setMessage(String message) {
        this.eventData.put(EVENT_MESSAGE, message);
    }

    /**
     * Retrieve the date and time the event occurred.
     * 
     * @return The Date associated with the event.
     */
    public Date getEventDateTime() {
        return (Date) this.eventData.get(EVENT_DATETIME);
    }

    /**
     * Set the date and time the event occurred in case it is not the same as when
     * the event was logged.
     * 
     * @param eventDateTime
     *          The event Date.
     */
    public void setEventDateTime(Date eventDateTime) {
        this.eventData.put(EVENT_DATETIME, eventDateTime);
    }

    /**
     * Set the type of event that occurred.
     * 
     * @param eventType
     *          The type of the event.
     */
    public void setEventType(String eventType) {
        this.eventData.put(EVENT_TYPE, eventType);
    }

    /**
     * Retrieve the type of the event.
     * 
     * @return The event type.
     */
    public String getEventType() {
        return (String) this.eventData.get(EVENT_TYPE);
    }

    /**
     * Add arbitrary attributes about the event.
     * 
     * @param name
     *          The attribute's key.
     * @param obj
     *          The data associated with the key.
     */
    public void put(String name, Serializable obj) {
        this.eventData.put(name, obj);
    }

    /**
     * Retrieve an event attribute.
     * 
     * @param name
     *          The attribute's key.
     * @return The value associated with the key or null if the key is not
     *         present.
     */
    public Serializable get(String name) {
        return (Serializable) this.eventData.get(name);
    }

    /**
     * Populate the event data from a Map.
     * 
     * @param data
     *          The Map to copy.
     */
    public void putAll(Map<String, Object> data) {
        this.eventData.putAll(data);
    }

    /**
     * Returns the number of attributes in the EventData.
     * 
     * @return the number of attributes in the EventData.
     */
    public int getSize() {
        return this.eventData.size();
    }

    /**
     * Returns an Iterator over all the entries in the EventDAta.
     * 
     * @return an Iterator that can be used to access all the event attributes.
     */
    public Iterator<Map.Entry<String, Object>> getEntrySetIterator() {
        return this.eventData.entrySet().iterator();
    }

    /**
     * Retrieve all the attributes in the EventData as a Map. Changes to this map
     * will be reflected in the EventData.
     * 
     * @return The Map of attributes in this EventData instance.
     */
    public Map<String, Object> getEventMap() {
        return this.eventData;
    }

    /**
     * Convert the EventData to a String.
     * 
     * @return The EventData as a String.
     */
    @Override
    public String toString() {
        return toXML();
    }

    /**
     * Compare two EventData objects for equality.
     * 
     * @param o
     *          The Object to compare.
     * @return true if the objects are the same instance or contain all the same
     *         keys and their values.
     */
    @SuppressWarnings("unchecked")
    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (!(o instanceof EventData || o instanceof Map)) {
            return false;
        }
        Map<String, Object> map = (o instanceof EventData) ? ((EventData) o).getEventMap() : (Map<String, Object>) o;

        return this.eventData.equals(map);
    }

    /**
     * Compute the hashCode for this EventData instance.
     * 
     * @return The hashcode for this EventData instance.
     */
    @Override
    public int hashCode() {
        return this.eventData.hashCode();
    }
}