001/*
002 * CDDL HEADER START
003 *
004 * The contents of this file are subject to the terms of the
005 * Common Development and Distribution License, Version 1.0 only
006 * (the "License").  You may not use this file except in compliance
007 * with the License.
008 *
009 * You can obtain a copy of the license at
010 * docs/licenses/cddl.txt
011 * or http://www.opensource.org/licenses/cddl1.php.
012 * See the License for the specific language governing permissions
013 * and limitations under the License.
014 *
015 * When distributing Covered Code, include this CDDL HEADER in each
016 * file and include the License file at
017 * docs/licenses/cddl.txt.  If applicable,
018 * add the following below this CDDL HEADER, with the fields enclosed
019 * by brackets "[]" replaced with your own identifying information:
020 *      Portions Copyright [yyyy] [name of copyright owner]
021 *
022 * CDDL HEADER END
023 *
024 *
025 *      Copyright 2013-2021 Ping Identity Corporation
026 */
027package com.unboundid.directory.sdk.common.types;
028
029
030/**
031 * Context used to provide named objects to Velocity templates as they are
032 * they are used to render output.  Objects stored in context are available
033 * to templates as they are rendered using variable references like
034 * '$variable'.
035 *
036 * See http://velocity.apache.org/ for more information on using Velocity.
037 */
038public interface VelocityContext
039{
040
041
042  /**
043   * Indicates whether a call to {@code put} will update this context
044   * if a value already exists in the context by the specified key.
045   *
046   * @return  boolean where true indicates overrides are permitted.
047   */
048  boolean isPermitOverrides();
049
050
051
052  /**
053   * Adds a named object to this context.  If overrides are not permitted
054   * and an object already exists in this context for the given key this
055   * method will throw a runtime exception.  Following a successful call
056   * to this method, the object will be available to templates using a
057   * reference like '$key'.
058   *
059   * @param key   The key with which to store the object in context.
060   *              Keys prefixed with a '_' are reserved for internal use.
061   *              Attempting to set a named object using a key prefixed with
062   *              '_' will throw a runtime exception.  Likewise attempting to
063   *              put a named object in this context with a previously used
064   *              key in which overrides are not permitted with throw a
065   *              runtime exception.
066   *
067   * @param value The context value.
068   *
069   * @return The old object or null if there was no old object.
070   */
071  Object put(String key, Object value);
072
073
074
075  /**
076   * Gets the named object associated with a given key.
077   *
078   * @param key associated with the named object.
079   *
080   * @return The associated named object within this context or {@code null}
081   *         if no object exists for the given key.
082   */
083  Object get(String key);
084
085
086
087  /**
088   * Indicates whether a named object exists in this context for a given key.
089   *
090   * @param key  to use for checking whether an associated object exists in
091   *             this context.
092   *
093   * @return boolean where true indicates a named object exists for the given
094   *         key.
095   */
096  boolean containsKey(Object key);
097
098
099
100  /**
101   * Obtains an array of all keys for this context.
102   *
103   * @return array of all keys for this context.
104   */
105  Object[] getKeys();
106
107
108
109  /**
110   * Removes the value associated with the specified key from the context.
111   *
112   * @param key The name of the value to remove.
113   *
114   * @return The value the key was mapped to, or {@code null} the key
115   *         was not previously associated with any named object in this
116   *         context.
117   */
118  Object remove(Object key);
119
120}