ConnectionEvent.java

/**
 * Alipay.com Inc.
 * Copyright (c) 2004-2012 All Rights Reserved.
 */
package com.alipay.zdal.datasource.resource.spi;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.util.EventObject;

import com.alipay.zdal.datasource.resource.util.id.SerialVersion;

/**
 * The ConnectionEvent class provides information about the source of a
 * Connection related event. A ConnectionEvent contains:
 * <ul>
 * 
 * <li>Type of connection event.</li>
 * <li>Managed connection instance that generated the event.</li>
 * <li>Connection handle associated with the managed connection.</li>
 * <li>Optionally an exception indicating an error.</li>
 * </ul>
 * <p>
 * This class is used for the following types of notifications:
 * <ul>
 * 
 * <li>Connection closed</li>
 * <li>Local transaction started</li>
 * <li>Local transaction commited</li>
 * <li>Local transaction rolled back</li>
 * <li>Connection error occurred</li>
 * </ul>
 * @version $Revision: 37390 $
 */
public class ConnectionEvent extends EventObject {
    /** @since 4.0.2 */
    static final long                        serialVersionUID;

    // Constants -----------------------------------------------------
    /**
     * These field names match the j2ee 1.4.1 ri version names
     */
    private static final ObjectStreamField[] serialPersistentFields;
    private static final int                 ID_IDX                       = 0;
    private static final int                 EXCEPTION_IDX                = 1;
    private static final int                 CONN_HANDLE_IDX              = 2;

    static {
        if (SerialVersion.version == SerialVersion.LEGACY) {
            serialVersionUID = 2776168349823367611L;
            serialPersistentFields = new ObjectStreamField[] {
            /** @serialField id int */
            new ObjectStreamField("id", int.class),
            /** @serialField e Exception */
            new ObjectStreamField("e", Exception.class),
            /** @serialField connectionHandle Object */
            new ObjectStreamField("connectionHandle", Object.class) };
        } else {
            // j2ee 1.4.1 RI values
            serialVersionUID = 5611772461379563249L;
            serialPersistentFields = new ObjectStreamField[] {
            /** @serialField id int */
            new ObjectStreamField("id", int.class),
            /** @serialField exception Exception */
            new ObjectStreamField("exception", Exception.class),
            /** @serialField connectionHandle Object */
            new ObjectStreamField("connectionHandle", Object.class) };
        }
    }

    /**
     * Connection has been closed
     */
    public static final int                  CONNECTION_CLOSED            = 1;

    /**
     * Local transaction has been started
     */
    public static final int                  LOCAL_TRANSACTION_STARTED    = 2;

    /**
     * Local transaction has been committed
     */
    public static final int                  LOCAL_TRANSACTION_COMMITTED  = 3;

    /**
     * Local transaction has been rolled back
     */
    public static final int                  LOCAL_TRANSACTION_ROLLEDBACK = 4;

    /**
     * Connection error has occurred
     */
    public static final int                  CONNECTION_ERROR_OCCURRED    = 5;

    /** Type of event */
    protected int                            id;

    /** The exception */
    private Exception                        e                            = null;
    /** The connectionHandle */
    private Object                           connectionHandle             = null;

    /**
     * Create a new ConnectionEvent
     *
     * @param source the source of the event
     * @param eid the event id
     */
    public ConnectionEvent(ManagedConnection source, int eid) {
        super(source);
        id = eid;
    }

    /**
     * Create a new ConnectionEvent
     *
     * @param source the source of the event
     * @param eid the event id
     * @param exception the exception associated with the event
     */
    public ConnectionEvent(ManagedConnection source, int eid, Exception exception) {
        super(source);
        id = eid;
        e = exception;
    }

    /**
     * Get the event type
     * 
     * @return the event id
     */
    public int getId() {
        return id;
    }

    /**
     * Get the exception
     * 
     * @return the exception
     */
    public Exception getException() {
        return e;
    }

    /**
     * Set the ConnectionHandle
     * 
     * @param connectionHandle the connection handle
     */
    public void setConnectionHandle(Object connectionHandle) {
        this.connectionHandle = connectionHandle;
    }

    /**
     * Get the ConnectionHandle
     * 
     * @return the connection handle
     */
    public Object getConnectionHandle() {
        return connectionHandle;
    }

    // Private -------------------------------------------------------
    private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
        ObjectInputStream.GetField fields = ois.readFields();
        String name = serialPersistentFields[ID_IDX].getName();
        this.id = fields.get(name, CONNECTION_ERROR_OCCURRED);
        name = serialPersistentFields[EXCEPTION_IDX].getName();
        this.e = (Exception) fields.get(name, null);
        name = serialPersistentFields[CONN_HANDLE_IDX].getName();
        this.connectionHandle = fields.get(name, null);
    }

    private void writeObject(ObjectOutputStream oos) throws IOException {
        // Write j2ee 1.4.1 RI field names
        ObjectOutputStream.PutField fields = oos.putFields();
        String name = serialPersistentFields[ID_IDX].getName();
        fields.put(name, id);
        name = serialPersistentFields[EXCEPTION_IDX].getName();
        fields.put(name, e);
        name = serialPersistentFields[CONN_HANDLE_IDX].getName();
        fields.put(name, connectionHandle);
        oos.writeFields();
    }

}