MWDescriptorInterfaceAliasPolicy.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.descriptor;

import java.util.List;

import org.eclipse.persistence.tools.workbench.mappingsmodel.MWModel;
import org.eclipse.persistence.tools.workbench.mappingsmodel.ProblemConstants;
import org.eclipse.persistence.tools.workbench.mappingsmodel.handles.MWClassHandle;
import org.eclipse.persistence.tools.workbench.mappingsmodel.handles.MWHandle;
import org.eclipse.persistence.tools.workbench.mappingsmodel.handles.MWHandle.NodeReferenceScrubber;
import org.eclipse.persistence.tools.workbench.mappingsmodel.meta.MWClass;
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;
import org.eclipse.persistence.oxm.mappings.XMLCompositeObjectMapping;

/**
 * A MWInterfaceAliasPolicy exists to allow the user to choose an interface
 * alias for a class descriptor. This is commonly used in cases such as RMI,
 * EJB, or CORBA, where you want to refer to everything as an interface. The
 * problem is, you really need some underlying class to contain attributes that
 * actually get mapped.
 */
public final class MWDescriptorInterfaceAliasPolicy extends MWAbstractDescriptorPolicy {

    private MWClassHandle interfaceAliasHandle;
        public final static String INTERFACE_ALIAS_PROPERTY = "interfaceAlias";


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

    private MWDescriptorInterfaceAliasPolicy() {
        // for TopLink use only
        super();
    }

    public MWDescriptorInterfaceAliasPolicy(MWMappingDescriptor descriptor) {
        super(descriptor);
    }


    // ********** initialization **********

    protected void initialize(Node parent) {
        super.initialize(parent);
        this.interfaceAliasHandle = new MWClassHandle(this, this.buildInterfaceAliasScrubber());
    }


    // ********** containment hierarchy **********

    protected void addChildrenTo(List children) {
        super.addChildrenTo(children);
        children.add(this.interfaceAliasHandle);
    }

    private NodeReferenceScrubber buildInterfaceAliasScrubber() {
        return new NodeReferenceScrubber() {
            public void nodeReferenceRemoved(Node node, MWHandle handle) {
                MWDescriptorInterfaceAliasPolicy.this.setInterfaceAlias(null);
            }
            public String toString() {
                return "MWDescriptorInterfaceAliasPolicy.buildInterfaceAliasScrubber()";
            }
        };
    }


    // ********** accessors **********

    public MWClass getInterfaceAlias() {
        return this.interfaceAliasHandle.getType();
    }

    public void setInterfaceAlias(MWClass newInterfaceAlias) {
        MWClass oldValue = getInterfaceAlias();
        this.interfaceAliasHandle.setType(newInterfaceAlias);
        // If you use an interface as an alias, it should be removed from the
        // project.
        if (newInterfaceAlias != null) {
            getOwningDescriptor().getProject().removeDescriptorForType(newInterfaceAlias);
        }
        firePropertyChanged(INTERFACE_ALIAS_PROPERTY, oldValue, interfaceAliasHandle.getType());
    }


    // ********** run-time **********

    public void adjustRuntimeDescriptor(ClassDescriptor runtimeDescriptor) {
        MWClass interfaceAlias = getInterfaceAlias();
        if (interfaceAlias != null) {
            runtimeDescriptor.getInterfacePolicy().addParentInterfaceName(getInterfaceAlias().getName());
        }
    }


    // ********** MWAbstractDescriptorPolicy implementation **********

    public MWDescriptorPolicy getPersistedPolicy() {
        return this;
    }

    public boolean isActive() {
        return true;
    }


    // ********** problems **********

    protected void addProblemsTo(List problems) {
        super.addProblemsTo(problems);
        this.checkInterfaceAlias(problems);
    }

    private void checkInterfaceAlias(List problems) {
        if (this.getInterfaceAlias() == null) {
            problems.add(this.buildProblem(ProblemConstants.DESCRIPTOR_INTERFACE_ALIAS_INTERFACE_SPECIFIED));
        }
    }


    // ********** misc **********

    public void toString(StringBuffer sb) {
        this.getInterfaceAlias().toString(sb);
    }


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

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

        XMLCompositeObjectMapping interfaceAliasHandleMapping = new XMLCompositeObjectMapping();
        interfaceAliasHandleMapping.setAttributeName("interfaceAliasHandle");
        interfaceAliasHandleMapping.setSetMethodName("setInterfaceAliasHandleForTopLink");
        interfaceAliasHandleMapping.setGetMethodName("getInterfaceAliasHandleForTopLink");
        interfaceAliasHandleMapping.setReferenceClass(MWClassHandle.class);
        interfaceAliasHandleMapping.setXPath("interface-alias-type-handle");
        descriptor.addMapping(interfaceAliasHandleMapping);
        return descriptor;
    }

    /**
     * check for null
     */
    private MWClassHandle getInterfaceAliasHandleForTopLink() {
        return (this.interfaceAliasHandle.getType() == null) ? null : this.interfaceAliasHandle;
    }
    private void setInterfaceAliasHandleForTopLink(MWClassHandle handle) {
        NodeReferenceScrubber scrubber = this.buildInterfaceAliasScrubber();
        this.interfaceAliasHandle = ((handle == null) ? new MWClassHandle(this, scrubber) : handle.setScrubber(scrubber));
    }
}