ManyToManySourceReferencePanel.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.mappingsplugin.ui.mapping.relational;

import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.eclipse.persistence.tools.workbench.framework.context.WorkbenchContextHolder;
import org.eclipse.persistence.tools.workbench.mappingsmodel.db.MWReference;
import org.eclipse.persistence.tools.workbench.mappingsmodel.db.MWTable;
import org.eclipse.persistence.tools.workbench.mappingsmodel.mapping.relational.MWManyToManyMapping;
import org.eclipse.persistence.tools.workbench.mappingsmodel.mapping.relational.MWTableReferenceMapping;
import org.eclipse.persistence.tools.workbench.uitools.app.PropertyValueModel;


/**
 * this is the panel used to pick (and/or build) the reference from the
 * "relation" table back to the mapping's "parent" descriptor
 */
final class ManyToManySourceReferencePanel
    extends AbstractTableReferencePanel
{

    ManyToManySourceReferencePanel(PropertyValueModel subjectHolder, WorkbenchContextHolder contextHolder) {
        super(subjectHolder, contextHolder);
    }

    /**
     * override because a many-to-many mapping does not have a single
     * set of candidate references; it has two, in the relation table:
     * source and target
     */
    protected Iterator candidateReferences(MWTableReferenceMapping mapping) {
        return ((MWManyToManyMapping) mapping).candidateRelationTableSourceReferences();
    }

    /**
     * setting the reference on a many-to-many mapping will set the
     * mapping's "source" reference
     */
    protected void setReference(MWReference reference) {
        super.setReference(reference);
        if (this.mapping().getRelationTable() == null) {
            this.mapping().setRelationTable(reference.getSourceTable());
        }
    }

    /**
     * the reference source is the "relation" table
     */
    protected List candidateNewReferenceSourceTables() {
        MWTable relationTable = this.mapping().getRelationTable();
        if (relationTable == null) {
            return super.candidateNewReferenceSourceTables();
        }
        return Collections.singletonList(relationTable);
    }

    /**
     * the reference source is the "relation" table
     */
    protected MWTable defaultNewReferenceSourceTable() {
        return this.mapping().getRelationTable();
    }

    /**
     * the reference target is one of the "parent" descriptor's tables
     */
    protected MWTable defaultNewReferenceTargetTable() {
        Iterator candidateTables = this.mapping().getParentRelationalDescriptor().candidateTables();
        return candidateTables.hasNext() ? (MWTable) candidateTables.next() : null;
    }

    private MWManyToManyMapping mapping() {
        return (MWManyToManyMapping) this.subject();
    }

}