All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • org.glassfish.pfl.dynamic.codegen.impl.AttributedObjectBase Maven / Gradle / Ivy

    /*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * 
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 * 
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 * 
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package org.glassfish.pfl.dynamic.codegen.impl;

import java.util.List ;
import java.util.ArrayList ;
import java.lang.Math ;

import org.glassfish.pfl.dynamic.copyobject.spi.Copy ;
import org.glassfish.pfl.dynamic.copyobject.spi.CopyInterceptor ;
import org.glassfish.pfl.dynamic.copyobject.spi.CopyType ;

/** An implementation of the AttributedObject interface.  This implementation
 * supports lazy copying of AttributedObject instances.
 */
public class AttributedObjectBase implements AttributedObject, CopyInterceptor {
    // Copying AttributedObjectBase is complicated, because we want to make
    // sure that after the copy, source and dest have the same attributes,
    // but whenever an attribute is set either in the source or the dest, it
    // is not visible to the other node.  We do this by making both the
    // source and the dest point to the same delegate, which carries the 
    // attributes originally present in the source.  This happens in 3 parts:
    // 1. The preCopy method is invoked, which introduces a new delegate in the
    //    source object, which carries the sources old delegate and attributes.
    // 2. During the copy, the destination object's delegate points to the source object.
    // 3. After the copy, the destination object's delegate is moved to the source 
    //    object's delegate in the postCopy method.
    // At this point, the source and dest share the same delegate, which contains the
    // original attributes of the source object.  Any set calls on either the 
    // source or dest will allocate a new attributes objects, which will be used for
    // all attribute setting.

    // This method is invoked on the source before the copy.  If the 
    // source has attributes, this causes the source to delegate to a new
    // AttributedObjectBase object which has the attributes that the source
    // originally had.  The source ends up having a delegate but no attributes.
    // If it also had a delegate originally, the new delegate delegates to the old
    // delegate.
    public void preCopy() {
	if (attributes != null) {
	    AttributedObjectBase base = new AttributedObjectBase() ;
	    base.delegate = this.delegate ;
	    this.delegate = base ;
	    base.attributes = this.attributes ;
	    this.attributes = null ;
	}
    }

    // This method is invoked on the result of the copy after all fields have been
    // copied.  If the result has a delegate, the delegate points to the source,
    // but we really want to point to the source's delegate, thus avoiding any conflict
    // between the source and the result setting attribute values.
    public void postCopy() {
	if (delegate != null)
	    delegate = delegate.delegate ;
    }

    @Copy(CopyType.SOURCE) // delegate is set to the source object in the copy
    private AttributedObjectBase delegate = null ;

    @Copy(CopyType.NULL) // attributes is set to null in the copy.
    private ArrayList attributes = null ;
    
    // The current dynamic attribute implementation is chosen
    // for simplicity and maximum possible performance in a simple case, 
    // not robust performance.  It is intended
    // to handle O( 10-20 ) attributes on a few thousands of AttributedObjects.
    // Obviously we can end up with very sparsely
    // occupied ArrayLists as more attributes are added.
    // This implementation is probably adequate for the codegen
    // library's needs, but a more efficient representation
    // (like a compressed bitmap index into an array of the
    // number of attributes set) could be needed if there are
    // hundreds or thousands of attributes on thousands of nodes.
    private void ensure( int index ) {
	if (attributes == null) {
	    attributes = new ArrayList( index+1 ) ;
	} else {
	    attributes.ensureCapacity( index+1 ) ;
	}

	// Make sure that any new elements of attributes
	// are set to null, otherwise set/get will throw
	// an IndexOutOfBounds exception.
	for (int ctr=attributes.size(); ctr<=index; ctr++) {
	    attributes.add( null ) ;
	}
    }

    public final Object get( int index ) {
	ensure( index ) ;
	Object result = null ;
	if (attributes != null)
	    result = attributes.get(index) ;

	if ((result == null) && (delegate != null))
	    result = delegate.get( index ) ;

	return result ;
    }

    public final void set( int index, Object obj ) {
	ensure( index ) ;
	attributes.set( index, obj ) ;
    }

    public final List attributes() {
	List delAttrs = null ;
	if (delegate != null)
	    delAttrs = delegate.attributes() ;

	if (delAttrs == null) {
	    return attributes ;
	} else {
	    int len = Math.max( attributes.size(), delAttrs.size() ) ;
	    List result = new ArrayList( len ) ;
	    for (int ctr=0; ctr    
    
    
    

    




    
    
    © 2015 - 2025 Weber Informatics LLC | Privacy Policy