content: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH & Co. KG (https://www.alkacon.com)
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library 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
   * Lesser General Public License for more details.
   *
   * For further information about Alkacon Software, please see the
   * company website: https://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: https://www.opencms.org
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.opencms.util;
  
  import org.opencms.jsp.util.CmsJspContentAccessValueWrapper;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * Returns the constant Object the map was initialized with for all {@link #get(Object)} calls,
   * regardless of what the actual key is.<p>
   *
   * @since 7.0.2
   *
   * @param <K> the type of keys maintained by this map
   * @param <V> the type of mapped values
   */
  @SuppressWarnings("unchecked")
  public class CmsConstantMap<K, V> implements Map<K, V> {
  
      /** Constant Map that always returns {@link Boolean#FALSE}.*/
      public static final Map<String, Boolean> CONSTANT_BOOLEAN_FALSE_MAP = new CmsConstantMap<String, Boolean>(
          Boolean.FALSE);
  
      /** Constant Map that always returns {@link Boolean#TRUE}.*/
      public static final Map<String, Boolean> CONSTANT_BOOLEAN_TRUE_MAP = new CmsConstantMap<String, Boolean>(
          Boolean.TRUE);
  
      /** Constant Map that always returns an empty list. */
      public static final Map<String, List<CmsJspContentAccessValueWrapper>> CONSTANT_EMPTY_LIST_MAP = new CmsConstantMap<String, List<CmsJspContentAccessValueWrapper>>(
          Collections.EMPTY_LIST);
  
      /** Constant Map that always returns an empty list. */
      public static final Map<String, String> CONSTANT_EMPTY_STRING_MAP = new CmsConstantMap<String, String>("".intern());
  
      /** The constant Object this map always returns. */
      private V m_constant;
  
      /**
       * Creates a new constant Map.<p>
       *
       * @param constant the constant to return for all {@link #get(Object)} calls.<p>
       */
      public CmsConstantMap(V constant) {
  
          m_constant = constant;
      }
  
      /**
       * @see java.util.Map#clear()
       */
      public void clear() {
  
          // NOOP
      }
  
      /**
       * @see java.util.Map#containsKey(java.lang.Object)
       */
      public boolean containsKey(Object key) {
  
          // this Map contains all keys, since all keys return the same value
          return true;
      }
  
      /**
       * @see java.util.Map#containsValue(java.lang.Object)
       */
      public boolean containsValue(Object value) {
  
          return m_constant.equals(value);
      }
  
      /**
       * @see java.util.Map#entrySet()
       */
      public Set<Map.Entry<K, V>> entrySet() {
  
          return Collections.emptySet();
      }
  
      /**
       * @see java.lang.Object#equals(java.lang.Object)
       */
      @Override
      public boolean equals(Object obj) {
  
          if (obj == this) {
              return true;
          }
          if (obj instanceof CmsConstantMap) {
              return m_constant.equals(((CmsConstantMap<?, ?>)obj).m_constant);
          }
          return false;
      }
  
      /**
       * @see java.util.Map#get(java.lang.Object)
       */
      public V get(Object key) {
  
          return m_constant;
      }
  
      /**
       * @see java.lang.Object#hashCode()
       */
      @Override
      public int hashCode() {
  
          return m_constant.hashCode();
      }
  
      /**
       * @see java.util.Map#isEmpty()
       */
      public boolean isEmpty() {
  
          return false;
      }
  
      /**
       * @see java.util.Map#keySet()
       */
      public Set<K> keySet() {
  
          return Collections.emptySet();
      }
  
      /**
       * @see java.util.Map#put(java.lang.Object, java.lang.Object)
       */
      public V put(Object arg0, Object arg1) {
  
          return null;
      }
  
      /**
       * @see java.util.Map#putAll(java.util.Map)
       */
      public void putAll(Map<? extends K, ? extends V> arg0) {
  
          // NOOP
      }
  
      /**
       * @see java.util.Map#remove(java.lang.Object)
       */
      public V remove(Object key) {
  
          return m_constant;
      }
  
      /**
       * @see java.util.Map#size()
       */
      public int size() {
  
          return 0;
      }
  
      /**
       * @see java.util.Map#values()
       */
      public Collection<V> values() {
  
          return Collections.singletonList(m_constant);
      }
  }