MWMappingHandle.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 java.util.Map;

import org.eclipse.persistence.tools.workbench.mappingsmodel.MWModel;
import org.eclipse.persistence.tools.workbench.mappingsmodel.descriptor.MWMappingDescriptor;
import org.eclipse.persistence.tools.workbench.mappingsmodel.mapping.MWMapping;
import org.eclipse.persistence.tools.workbench.mappingsmodel.meta.MWClass;
import org.eclipse.persistence.tools.workbench.utility.ClassTools;
import org.eclipse.persistence.tools.workbench.utility.node.Node;

import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.mappings.OneToOneMapping;
import org.eclipse.persistence.oxm.XMLDescriptor;

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

    /**
     * This is the actual mapping.
     * It is built from the descriptor and mapping names, below.
     */
    private volatile MWMapping mapping;

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

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

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

    public MWMappingHandle(MWModel parent, MWMapping mapping, NodeReferenceScrubber scrubber) {
        super(parent, scrubber);
        this.mapping = mapping;
    }


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

    public MWMapping getMapping() {
        return this.mapping;
    }

    public void setMapping(MWMapping mapping) {
        this.mapping = mapping;
    }

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

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

    public void postProjectBuild() {
        super.postProjectBuild();
        if (this.mappingDescriptorName != null && this.mappingName != null) {
            MWMappingDescriptor mappingDescriptor = (MWMappingDescriptor) this.getProject().descriptorNamed(mappingDescriptorName);
            if (mappingDescriptor != null) {
                this.mapping = mappingDescriptor.mappingNamed(this.mappingName);
            }
        }
        // Ensure mappingDescriptorName and mappingName 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.mappingDescriptorName = null;
        this.mappingName = null;
    }

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

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


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

    public static XMLDescriptor buildDescriptor() {
        XMLDescriptor descriptor = new XMLDescriptor();
        descriptor.setJavaClass(MWMappingHandle.class);

        descriptor.addDirectMapping("mappingDescriptorName", "getMappingDescriptorNameForToplink", "setMappingDescriptorNameForToplink", "mapping-descriptor-name/text()");
        descriptor.addDirectMapping("mappingName", "getMappingNameForToplink", "setMappingNameForToplink", "mapping-name/text()");

        return descriptor;
    }

    private String getMappingDescriptorNameForToplink() {
        return (this.mapping == null) ? null : this.mapping.getParentDescriptor().getName();
    }

    private void setMappingDescriptorNameForToplink(String mappingDescriptorName) {
        this.mappingDescriptorName = mappingDescriptorName;
    }

    private String getMappingNameForToplink() {
        return (this.mapping == null) ? null : this.mapping.getName();
    }

    private void setMappingNameForToplink(String mappingName) {
        this.mappingName = mappingName;
    }

}