001/*
002 * The contents of this file are subject to the terms of the Common Development and
003 * Distribution License (the License). You may not use this file except in compliance with the
004 * License.
005 *
006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
007 * specific language governing permission and limitations under the License.
008 *
009 * When distributing Covered Software, include this CDDL Header Notice in each file and include
010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
011 * Header, with the fields enclosed by brackets [] replaced by your own identifying
012 * information: "Portions Copyright [year] [name of copyright owner]".
013 *
014 * Copyright 2008 Sun Microsystems, Inc.
015 * Portions Copyright 2016 ForgeRock AS.
016 */
017package org.forgerock.opendj.config;
018
019/**
020 * An interface for determining the default behavior of a property. A property
021 * exhibits default behavior when it has no values defined. There are four
022 * different types of default behavior:
023 * <ol>
024 * <li>there is no default behavior - e.g. leaving a "description" unset has no
025 * side-effects. This default behavior is represented using the
026 * {@link UndefinedDefaultBehaviorProvider} implementation
027 * <li>the property defaults to one or more real values of the property. This
028 * default behavior is represented using the
029 * {@link DefinedDefaultBehaviorProvider} implementation
030 * <li>the property defaults to some special behavior that cannot be represented
031 * using real property values. This default behavior is represented using the
032 * {@link AliasDefaultBehaviorProvider} implementation
033 * <li>the property inherits its values from property held in another managed
034 * object (e.g. the parent managed object). This default behavior is represented
035 * using the {@link AbsoluteInheritedDefaultBehaviorProvider} and
036 * {@link RelativeInheritedDefaultBehaviorProvider} implementations.
037 * </ol>
038 * An application can perform actions based on the type of the default behavior
039 * by implementing the {@link DefaultBehaviorProviderVisitor} interface.
040 *
041 * @param <T>
042 *            The type of values represented by this provider.
043 */
044public abstract class DefaultBehaviorProvider<T> {
045
046    /** Creates a new default behavior provider. */
047    protected DefaultBehaviorProvider() {
048        // No implementation required.
049    }
050
051    /**
052     * Apply a visitor to this default behavior provider.
053     *
054     * @param <R>
055     *            The return type of the visitor's methods.
056     * @param <P>
057     *            The type of the additional parameters to the visitor's
058     *            methods.
059     * @param v
060     *            The default behavior visitor.
061     * @param p
062     *            Optional additional visitor parameter.
063     * @return Returns a result as specified by the visitor.
064     */
065    public abstract <R, P> R accept(DefaultBehaviorProviderVisitor<T, R, P> v, P p);
066
067    /**
068     * Performs any run-time initialization required by this default behavior
069     * provider. This may include resolving managed object paths and property
070     * names.
071     * <p>
072     * The default implementation is to do nothing.
073     *
074     * @throws Exception
075     *             If this default behavior provider could not be initialized.
076     */
077    protected void initialize() throws Exception {
078        // Default implementation is to do nothing.
079    }
080
081}