MWQueryKeyHandle.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.mappingsmodel.handles;

import org.eclipse.persistence.tools.workbench.mappingsmodel.MWModel;
import org.eclipse.persistence.tools.workbench.mappingsmodel.MWQueryKey;
import org.eclipse.persistence.tools.workbench.mappingsmodel.descriptor.relational.MWRelationalDescriptor;
import org.eclipse.persistence.tools.workbench.utility.node.Node;

import org.eclipse.persistence.oxm.XMLDescriptor;

/**
 * MWQueryKeyHandle is used to isolate the painful bits of code
 * necessary to correctly handle references to MWQueryKeys.
 * Since a MWQueryKey is nested within the XML file
 * for a MWDescriptor, we need to store a reference to a particular
 * query key as a pair of instance variables:
 *   - the name of the containing descriptor
 *   - the name of the query key
 *
 * This causes no end of pain when dealing with TopLink, property
 * change listeners, backward-compatibility, etc.
 */
public final class MWQueryKeyHandle extends MWHandle {

    /**
     * This is the actual query key.
     * It is built from the descriptor and query key names, below.
     */
    private volatile MWQueryKey queryKey;

    /**
     * The descriptor and query key names are transient. They
     * are used only to hold their values until postProjectBuild()
     * is called and we can resolve the actual query key.
     * We do not keep these in synch with the query key itself because
     * we cannot know when the query key has been renamed etc.
     */
    private volatile String descriptorName;
    private volatile String queryKeyName;


    // ********** constructors **********

    /**
     * default constructor - for TopLink use only
     */
    private MWQueryKeyHandle() {
        super();
    }

    public MWQueryKeyHandle(MWModel parent, NodeReferenceScrubber scrubber) {
        super(parent, scrubber);
    }

    public MWQueryKeyHandle(MWModel parent, MWQueryKey queryKey, NodeReferenceScrubber scrubber) {
        super(parent, scrubber);
        this.queryKey = queryKey;
    }


    // ********** instance methods **********

    public MWQueryKey getQueryKey() {
        return this.queryKey;
    }

    public void setQueryKey(MWQueryKey queryKey) {
        this.queryKey = queryKey;
    }

    protected Node node() {
        return getQueryKey();
    }

    public MWQueryKeyHandle setScrubber(NodeReferenceScrubber scrubber) {
        this.setScrubberInternal(scrubber);
        return this;
    }

    public void resolveColumnHandles() {
        super.resolveColumnHandles();

        if (this.descriptorName != null && this.queryKeyName != null) {
            MWRelationalDescriptor descriptor = (MWRelationalDescriptor) this.getProject().descriptorNamed(this.descriptorName);
            if (descriptor != null) {
                this.queryKey = descriptor.queryKeyNamed(this.queryKeyName);
            }
        }

        // Ensure descriptorName and queryKeyName are not used by setting them to null....
        // If the XML is corrupt and only one of these attributes is populated,
        // this will cause the populated attribute to be cleared out if the
        // objects are rewritten.
        this.descriptorName = null;
        this.queryKeyName = null;
    }

    /**
     * Override to delegate comparison to the queryKey itself.
     * If the handles being compared are in a collection that is being sorted,
     * NEITHER query key should be null.
     */
    public int compareTo(Object o) {
        return this.queryKey.compareTo(((MWQueryKeyHandle) o).queryKey);
    }

    public void toString(StringBuffer sb) {
        if (this.queryKey == null) {
            sb.append("null");
        } else {
            sb.append(this.queryKey.getName());
        }
    }


    // ********** TopLink methods **********

    public static XMLDescriptor buildDescriptor() {
        XMLDescriptor descriptor = new XMLDescriptor();

        descriptor.setJavaClass(MWQueryKeyHandle.class);

        descriptor.addDirectMapping("descriptorName", "getDescriptorNameForTopLink", "setDescriptorNameForTopLink", "descriptor-name/text()");
        descriptor.addDirectMapping("queryKeyName", "getQueryKeyNameForTopLink", "setQueryKeyNameForTopLink", "query-key-name/text()");

        return descriptor;
    }

    private String getDescriptorNameForTopLink(){
        return (this.queryKey == null) ? null : this.queryKey.getDescriptor().getName();
    }

    private void setDescriptorNameForTopLink(String descriptorName){
        this.descriptorName = descriptorName;
    }

    private String getQueryKeyNameForTopLink() {
        return (this.queryKey == null) ? null : this.queryKey.getName();
    }

    private void setQueryKeyNameForTopLink(String queryKeyName) {
        this.queryKeyName = queryKeyName;
    }

}