DatabaseTypeHandle.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.db;

import org.eclipse.persistence.tools.workbench.mappingsmodel.handles.MWHandle;
import org.eclipse.persistence.tools.workbench.platformsmodel.DatabasePlatform;
import org.eclipse.persistence.tools.workbench.platformsmodel.DatabaseType;
import org.eclipse.persistence.tools.workbench.utility.node.Node;


/**
 * This handle is a bit different from the other handles.
 * It references an object that is completely outside of the project
 * and is only used by database fields.
 */
final class DatabaseTypeHandle
    extends MWHandle
{

    /**
     * This is the actual database type.
     * It is built from the database type name, below.
     */
    private volatile DatabaseType databaseType;

    /**
     * The database type name is transient. It
     * is used only to hold its value until #postProjectBuild()
     * is called and we can resolve the actual database type.
     * We do not keep it in synch with the database type itself because
     * we cannot know when the database type has been renamed etc.
     */
    private volatile String databaseTypeName;

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

    DatabaseTypeHandle(MWColumn parent) {
        // database types are never removed
        super(parent, NodeReferenceScrubber.NULL_INSTANCE);
    }


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

    DatabaseType getDatabaseType() {
        return this.databaseType;
    }

    void setDatabaseType(DatabaseType databaseType) {
        this.databaseType = databaseType;
    }

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

    private DatabasePlatform databasePlatform() {
        return this.getDatabase().getDatabasePlatform();
    }

    public void postProjectBuild() {
        if (this.databaseTypeName == null) {
            // bug 3856524 - databaseType can be null in legacy projects
            this.databaseType = this.databasePlatform().defaultDatabaseType();
        } else {
            try {
                this.databaseType = this.databasePlatform().databaseTypeNamed(this.databaseTypeName);
            } catch (IllegalArgumentException ex) {
                // we have really hosed up the database types in the past - try
                // to fix them here...
                this.databaseType = this.databasePlatform().defaultDatabaseType();
            }
        }
        // ensure databaseTypeName is not used by setting it to null....
        this.databaseTypeName = null;
    }

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

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


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

    String getDatabaseTypeNameForTopLink() {
        return (this.databaseType == null) ? null : this.databaseType.getName();
    }

    void setDatabaseTypeNameForTopLink(String name) {
        this.databaseTypeName = name;
    }

}