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 */
016package org.opends.server.admin;
017
018
019
020/**
021 * An interface for determining the default behavior of a property. A
022 * property exhibits default behavior when it has no values defined.
023 * There are four different types of default behavior:
024 * <ol>
025 * <li>there is no default behavior - e.g. leaving a "description"
026 * unset has no side-effects. This default behavior is represented
027 * using the {@link UndefinedDefaultBehaviorProvider} implementation
028 * <li>the property defaults to one or more real values of the
029 * property. This default behavior is represented using the
030 * {@link DefinedDefaultBehaviorProvider} implementation
031 * <li>the property defaults to some special behavior that cannot be
032 * represented using real property values. This default behavior is
033 * represented using the {@link AliasDefaultBehaviorProvider}
034 * implementation
035 * <li>the property inherits its values from property held in another
036 * managed object (e.g. the parent managed object). This default
037 * behavior is represented using the
038 * {@link AbsoluteInheritedDefaultBehaviorProvider} and
039 * {@link RelativeInheritedDefaultBehaviorProvider} implementations.
040 * </ol>
041 * An application can perform actions based on the type of the default
042 * behavior by implementing the {@link DefaultBehaviorProviderVisitor}
043 * interface.
044 *
045 * @param <T>
046 *          The type of values represented by this provider.
047 */
048public abstract class DefaultBehaviorProvider<T> {
049
050  /**
051   * Creates a new default behavior provider.
052   */
053  protected DefaultBehaviorProvider() {
054    // No implementation required.
055  }
056
057
058
059  /**
060   * Apply a visitor to this default behavior provider.
061   *
062   * @param <R>
063   *          The return type of the visitor's methods.
064   * @param <P>
065   *          The type of the additional parameters to the visitor's
066   *          methods.
067   * @param v
068   *          The default behavior visitor.
069   * @param p
070   *          Optional additional visitor parameter.
071   * @return Returns a result as specified by the visitor.
072   */
073  public abstract <R, P>
074  R accept(DefaultBehaviorProviderVisitor<T, R, P> v, P p);
075
076
077
078  /**
079   * Performs any run-time initialization required by this default
080   * behavior provider. This may include resolving managed object
081   * paths and property names.
082   * <p>
083   * The default implementation is to do nothing.
084   *
085   * @throws Exception
086   *           If this default behavior provider could not be
087   *           initialized.
088   */
089  protected void initialize() throws Exception {
090    // Default implementation is to do nothing.
091  }
092
093}