objectcontainer.java

Java的面向对象数据库系统的源代码

// You can redistribute this software and/or modify it under the terms of
// the Ozone Core License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-@year@ by SMB GmbH. All rights reserved.
//
// $Id: ObjectContainer.java,v 1.7 2003/04/06 13:57:33 mediumnet Exp $

package org.ozoneDB.core;

import org.ozoneDB.*;
import org.ozoneDB.core.dr.Lockable;


/**
 * Together with the {@link StoreManager} interface this is part of the
 * StoreManager back-end API.<p>
 *
 * An ObjectContainer wraps a target (database) object and decorates it with
 * functionality needed by the database system, such as the corresponding object
 * ID. Also, the ObjectContainer is the delegate for the methods defined by
 * {@link OzoneCompatible}.
 *
 *
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @author <A HREF="http://www.medium.net/">Medium.net</A>
 * @version $Revision: 1.7 $Date: 2003/04/06 13:57:33 $
 */
public interface ObjectContainer extends Lockable {

    public final static String PROXYNAME_POSTFIX = "_Proxy";
    public final static String IMPLNAME_POSTFIX = "_Impl";

    // possible return values of the state() method
    public final static int STATE_CLEAN = 0;
    public final static int STATE_READ = 1;
    public final static int STATE_MODIFIED = 2;
    public final static int STATE_CREATED = 4;
    public final static int STATE_DELETED = 8;

    /**
     * Return the current state of the container. Possible return values are the
     * STATE constants defined in this class. A container can only be in one of
     * these states at one time. The state of a container can only be raised
     * during one transaction. So, if a container is created (STATE_CREATED)
     * during a transaction, the state can become STATE_DELETED only.
     *
     *
     * @return The state of the container.
     */
    public int state();


    /**
     * Returns the time when the container was last commited with lock level
     * greater than Lock.LEVEL_READ. The value returned by this method should
     * only be compared against return values of this method.
     */
    public long modTime();


    public Lock lock();


    public void touch();


    public void setName( String _name );


    public String name();


    public void setTarget( OzoneCompatible _target );


    public OzoneCompatible target();


    public Class targetClass();


    public void createTarget( Env env, Class cl, String sig, Object[] args ) throws Exception;


    public Object invokeTarget( Env env, String methodName, String sig, Object[] args ) throws Exception;


    public Object invokeTarget( Env env, int methodIndex, Object[] args ) throws Exception;


    public void deleteTarget();


    public void nameTarget( String _name );


    public OzoneCompatible targetClone() throws Exception;


    /**
     * @return True if obj and receiver point to the same target object.
     */
    public boolean equals( Object obj );


    /**
     * Return a proxy for the receiver.
     * @return Proxy for this object.
     */
    public OzoneProxy ozoneProxy();


    public ObjectID id();


    public OzoneInterface database();


    public Permissions permissions();


	/**
		Pins this ObjectContainer.
		Every caller of this method must pair this call with a call to {@link #unpin}.
		An ObjectContainer remains in main memory at least as long as it is pinned.
	*/
	public void pin();

	/**
		Unpins this ObjectContainer.
		This method must be called exactly once for every call to {@link #pin}.
	*/
	public void unpin();

	/**
		Returns wether this ObjectContainer is pinned.
	*/
	public boolean isPinned();

    /**
    	Ensures that the garbageCollectionLevel is at least the given currentGarbageCollectionLevel.
    	The return value is meaningful if the supplied newGarbageCollectionLevel is the currentGarbageCollectionLevel

    	@return
    		<=0 if this object still has to be processed.
    			This is the case if it belongs to the surelyReachable set but not to the processedReachable set
    		> otherwise

    		<0 if this object has been updated
    		=0 if this object has not been updated, it is surelyReachable
    		>0 if this object has not been updated, it is processedReachable
    */
    public int ensureGarbageCollectionLevel(int newGarbageCollectionLevel);

    /**
    	Returns the garbageCollectionLevel this ObjectContainer has reached due to (not) calling {@link #ensureGarbageCollectionLevel}.
    */
    public int getGarbageCollectionLevel();

    public boolean shouldOnActivateBeCalled();

    public void invokeOnActivate();

    public void invokeOnPassivate();

    boolean shouldOnPassivateBeCalled();
    
    public void requireWriteLocking();

    void setShouldCallOnPassivate(boolean shouldOnPassivateBeCalled);

    void setShouldCallOnActivate(boolean shouldOnActivateBeCalled);

}

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