NullDirectory.java

/*
** Module   : NullDirectory.java
** Abstract : safe placeholder that simply returns the initial value (there
**            is no directory lookup)
**
** Copyright (c) 2008-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- --JPRM-- ----------------Description-----------------
** 001 GES 20080409 @37910   Created initial version which provides a
**                           safe placeholder that simply returns the
**                           initial value (there is no directory lookup).
** 002 HC  20180813          Added double data type to the directory access interface.
** 003 HC  20200130          Added a method for enumerating nodes.
** 004 GBB 20240709          Added method getBoolean for wrapper class Boolean.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
** 
**   0. Attribution Requirement.
** 
**     You must preserve all legal notices or author attributions in the covered
**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
**     credit already included within the covered work.
** 
**   1. No License To Use Trademarks.
** 
**     This license does not grant any license or rights to use the trademarks
**     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
**     of Golden Code Development Corporation. You are not authorized to use the
**     name Golden Code, FWD, or the names of any author or contributor, for
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** 
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** 
**     You may not represent yourself as Golden Code Development Corporation or FWD.
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**     Golden Code Development Corporation, FWD, or any author or contributor to
**     the covered work, without written authorization.
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**     versions of the covered work must be marked in a reasonable way to make it
**     clear that the modified work is not originating from Golden Code Development
**     Corporation or FWD.  All modified versions must contain the notices of
**     attribution required in this license.
*/

package com.goldencode.p2j.directory;

import java.util.*;

/**
 * Provides a safe placeholder that simply returns the initial value (there
 * is no directory lookup).
 */
public class NullDirectory
implements Directory
{
   /**
    * Access a data value from the directory as specified by the given
    * absolute or relative node ID.
    *
    * @param    search
    *           Must be one of <code>ID_ABSOLUTE</code> (if the given node
    *           ID includes all paths from the root of the directory tree to
    *           the node being read) or <code>ID_RELATIVE</code> if the given
    *           ID is only a relative portion which should be found via a
    *           search through a standard set of search paths.
    * @param    id
    *           The node ID to retrieve.
    * @param    initial
    *           The initial value to return if a node of the proper type is
    *           not found by the given node ID or if no node is found by the
    *           given node ID.
    *
    * @return   The data value at that node ID or the default initial value.
    */
   @Override
   public String getString(int search, String id, String initial)
   {
      return initial;
   }

   /**
    * {@inheritDoc}
    */
   @Override
   public List<String> getStrings(int search, String id)
   {
      return Collections.emptyList();
   }

   /**
    * Access a data value from the directory as specified by the given
    * absolute or relative node ID.
    *
    * @param    search
    *           Must be one of <code>ID_ABSOLUTE</code> (if the given node
    *           ID includes all paths from the root of the directory tree to
    *           the node being read) or <code>ID_RELATIVE</code> if the given
    *           ID is only a relative portion which should be found via a
    *           search through a standard set of search paths.
    * @param    id
    *           The node ID to retrieve.
    * @param    initial
    *           The initial value to return if a node of the proper type is
    *           not found by the given node ID or if no node is found by the
    *           given node ID.
    *
    * @return   The data value at that node ID or the default initial value.
    */
   @Override
   public char getChar(int search, String id, char initial)
   {
      return initial;
   }
   
   /**
    * Access a data value from the directory as specified by the given
    * absolute or relative node ID.
    *
    * @param    search
    *           Must be one of <code>ID_ABSOLUTE</code> (if the given node
    *           ID includes all paths from the root of the directory tree to
    *           the node being read) or <code>ID_RELATIVE</code> if the given
    *           ID is only a relative portion which should be found via a
    *           search through a standard set of search paths.
    * @param    id
    *           The node ID to retrieve.
    * @param    initial
    *           The initial value to return if a node of the proper type is
    *           not found by the given node ID or if no node is found by the
    *           given node ID.
    *
    * @return   The data value at that node ID or the default initial value.
    */
   @Override
   public int getInt(int search, String id, int initial)
   {
      return initial;
   }

   /**
    * Access a data value from the directory as specified by the given
    * absolute or relative node ID.
    *
    * @param    search
    *           Must be one of <code>ID_ABSOLUTE</code> (if the given node
    *           ID includes all paths from the root of the directory tree to
    *           the node being read) or <code>ID_RELATIVE</code> if the given
    *           ID is only a relative portion which should be found via a
    *           search through a standard set of search paths.
    * @param    id
    *           The node ID to retrieve.
    * @param    initial
    *           The initial value to return if a node of the proper type is
    *           not found by the given node ID or if no node is found by the
    *           given node ID.
    *
    * @return   The data value at that node ID or the default initial value.
    */
   @Override
   public double getDouble(int search, String id, double initial)
   {
      return initial;
   }

   /**
    * Access a data value from the directory as specified by the given
    * absolute or relative node ID.
    *
    * @param    search
    *           Must be one of <code>ID_ABSOLUTE</code> (if the given node
    *           ID includes all paths from the root of the directory tree to
    *           the node being read) or <code>ID_RELATIVE</code> if the given
    *           ID is only a relative portion which should be found via a
    *           search through a standard set of search paths.
    * @param    id
    *           The node ID to retrieve.
    * @param    initial
    *           The initial value to return if a node of the proper type is
    *           not found by the given node ID or if no node is found by the
    *           given node ID.
    *
    * @return   The data value at that node ID or the default initial value.
    */
   @Override
   public boolean getBoolean(int search, String id, boolean initial)
   {
      return initial;
   }

   /**
    * Access a data value from the directory as specified by the given
    * absolute or relative node ID.
    *
    * @param    search
    *           Must be one of <code>ID_ABSOLUTE</code> (if the given node
    *           ID includes all paths from the root of the directory tree to
    *           the node being read) or <code>ID_RELATIVE</code> if the given
    *           ID is only a relative portion which should be found via a
    *           search through a standard set of search paths.
    * @param    id
    *           The node ID to retrieve.
    * @param    initial
    *           The initial value to return if a node of the proper type is
    *           not found by the given node ID or if no node is found by the
    *           given node ID.
    *
    * @return   The data value at that node ID or the default initial value.
    */
   @Override
   public Boolean getBoolean(int search, String id, Boolean initial)
   {
      return initial;
   }
   
   /**
    * {@inheritDoc}
    */
   @Override
   public List<String> enumerateNodes(int search, String id)
   {
      return Collections.emptyList();
   }
}