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 GmbH & Co. KG, 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.workplace.tools;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Default implementation of a named object container. <p>
   *
   * It can handle relative or absolute orderings and unique names.<p>
   *
   * @param <T> the type of objects
   *
   * @since 6.0.0
   */
  public class CmsIdentifiableObjectContainer<T> {
  
      /**
       * Internal class just for taking care of the positions in the container.<p>
       *
       * @param <T> the object type
       *
       * @since 6.0.0
       */
      private static class CmsIdObjectElement<T> {
  
          /** Identifiable object. */
          private final T m_object;
  
          /** Relative position. */
          private final float m_position;
  
          /**
           * Default Constructor.<p>
           *
           * @param object the object
           * @param position the relative position
           *
           */
          public CmsIdObjectElement(T object, float position) {
  
              m_object = object;
              m_position = position;
          }
  
          /**
           * Returns the object.<p>
           *
           * @return the object
           */
          public T getObject() {
  
              return m_object;
          }
  
          /**
           * Returns the position.<p>
           *
           * @return the position
           */
          public float getPosition() {
  
              return m_position;
          }
  
      }
  
      /** Cache for element list. */
      private List<T> m_cache;
  
      /** List of objects. */
      private final List<T> m_objectList = new ArrayList<T>();
  
      /** Map of objects only used if uniqueIds flag set. */
      private final Map<String, T> m_objectsById = new HashMap<String, T>();
  
      /** Map of object lists by id. */
      private final Map<String, List<T>> m_objectsListsById = new HashMap<String, List<T>>();
  
      /** List of ordered objects. */
      private final List<CmsIdObjectElement<T>> m_orderedObjectList = new ArrayList<CmsIdObjectElement<T>>();
  
      /** Flag for managing absolute and relative ordering. */
      private final boolean m_relativeOrdered;
  
      /** Flag for managing uniqueness check. */
      private final boolean m_uniqueIds;
  
      /**
       * Default Constructor.<p>
       *
       * @param uniqueIds if the list show check for unique ids
       * @param relativeOrdered if the list show use relative ordering, instead of absolute ordering
       */
      public CmsIdentifiableObjectContainer(boolean uniqueIds, boolean relativeOrdered) {
  
          m_uniqueIds = uniqueIds;
          m_relativeOrdered = relativeOrdered;
      }
  
      /**
       * Appends the specified object to the end of this container. <p>
       *
       * @param id the object identifier
       * @param idObject the object add to the container
       *
       * @see java.util.List#add(Object)
       */
      public void addIdentifiableObject(String id, T idObject) {
  
          m_cache = null;
          if (m_uniqueIds && (m_objectsById.get(id) != null)) {
              removeObject(id);
          }
          if (m_relativeOrdered) {
              float pos = 1;
              if (!m_orderedObjectList.isEmpty()) {
                  pos = m_orderedObjectList.get(m_orderedObjectList.size() - 1).getPosition() + 1;
              }
              m_orderedObjectList.add(new CmsIdObjectElement<T>(idObject, pos));
          } else {
              m_objectList.add(idObject);
          }
          if (m_uniqueIds) {
              m_objectsById.put(id, idObject);
          } else {
              List<T> prevObj = m_objectsListsById.get(id);
              if (prevObj == null) {
                  List<T> list = new ArrayList<T>();
                  list.add(idObject);
                  m_objectsListsById.put(id, list);
              } else {
                  prevObj.add(idObject);
              }
          }
  
      }
  
      /**
       * Inserts the specified object at the specified position in this container.<p>
       *
       * Shifts the object currently at that position (if any) and any subsequent
       * objects to the right (adds one to their indices).<p>
       *
       * @param id the object identifier
       * @param idObject the object add to the container
       * @param position the insertion point
       *
       * @see java.util.List#add(int, Object)
       */
      public void addIdentifiableObject(String id, T idObject, float position) {
  
          m_cache = null;
          if (m_uniqueIds && (m_objectsById.get(id) != null)) {
              removeObject(id);
          }
          if (m_relativeOrdered) {
              int pos = 0;
              Iterator<CmsIdObjectElement<T>> itElems = m_orderedObjectList.iterator();
              while (itElems.hasNext()) {
                  CmsIdObjectElement<T> element = itElems.next();
                  if (element.getPosition() > position) {
                      break;
                  }
                  pos++;
              }
              m_orderedObjectList.add(pos, new CmsIdObjectElement<T>(idObject, position));
          } else {
              m_objectList.add((int)position, idObject);
          }
          if (m_uniqueIds) {
              m_objectsById.put(id, idObject);
          } else {
              List<T> prevObj = m_objectsListsById.get(id);
              if (prevObj == null) {
                  List<T> list = new ArrayList<T>();
                  list.add(idObject);
                  m_objectsListsById.put(id, list);
              } else {
                  prevObj.add(idObject);
              }
          }
  
      }
  
      /**
       * Resets the container.<p>
       */
      public void clear() {
  
          m_cache = null;
          m_objectList.clear();
          m_objectsById.clear();
          m_orderedObjectList.clear();
          m_objectsListsById.clear();
      }
  
      /**
       * Returns the list of objects.<p>
       *
       * @return the a list of <code>{@link Object}</code>s.
       */
      public List<T> elementList() {
  
          if (m_cache != null) {
              return m_cache;
          }
          if (m_relativeOrdered) {
              List<T> objectList = new ArrayList<T>();
              Iterator<CmsIdObjectElement<T>> itObjs = m_orderedObjectList.iterator();
              while (itObjs.hasNext()) {
                  CmsIdObjectElement<T> object = itObjs.next();
                  objectList.add(object.getObject());
              }
              m_cache = Collections.unmodifiableList(objectList);
          } else {
              m_cache = Collections.unmodifiableList(m_objectList);
          }
          return m_cache;
      }
  
      /**
       * Returns the object with the given id.<p>
       *
       * If <code>uniqueIds</code> is set to <code>false</code> an <code>{@link Object}</code>
       * containing a <code>{@link List}</code> with all the objects with the given id is returned.<p>
       *
       * If the container no contains any object with the given id, <code>null</code> is returned.<p>
       *
       * @param id the id of the object
       *
       * @return the object if found, or <code>null</code>
       *
       * @see java.util.Map#get(Object)
       */
      public T getObject(String id) {
  
          if (!m_uniqueIds) {
              throw new UnsupportedOperationException("Not supported for not unique ids");
          }
          return m_objectsById.get(id);
  
      }
  
      /**
       * Returns the list of objects with the given id.<p>
       *
       * @param id the object id
       *
       * @return the list of objects if found, or <code>null</code>
       */
      public List<T> getObjectList(String id) {
  
          if (m_uniqueIds) {
              throw new UnsupportedOperationException("Not supported for unique ids");
          }
          return m_objectsListsById.get(id);
      }
  
      /**
       * Removes an object with the given id.<p>
       *
       * if <code>m_uniqueIds</code> is set, it will remove at most one object.
       * otherwise it will remove all elements with the given id.<p>
       *
       * @param id the id of the object to remove
       */
      public synchronized void removeObject(String id) {
  
          m_cache = null;
          if (m_relativeOrdered) {
              if (m_uniqueIds) {
                  Object o = getObject(id);
                  Iterator<CmsIdObjectElement<T>> itObjs = m_orderedObjectList.iterator();
                  while (itObjs.hasNext()) {
                      CmsIdObjectElement<T> object = itObjs.next();
                      if (object.getObject() == o) {
                          itObjs.remove();
                          break;
                      }
                  }
                  m_objectsById.remove(id);
              } else {
                  Iterator<T> itRemove = m_objectsListsById.get(id).iterator();
                  while (itRemove.hasNext()) {
                      T o = itRemove.next();
                      Iterator<CmsIdObjectElement<T>> itObjs = m_orderedObjectList.iterator();
                      while (itObjs.hasNext()) {
                          CmsIdObjectElement<T> object = itObjs.next();
                          if (object.getObject() == o) {
                              itObjs.remove();
                              break;
                          }
                      }
                  }
                  m_orderedObjectList.remove(id);
              }
          } else {
              Object o = getObject(id);
              m_objectList.remove(o);
              if (m_uniqueIds) {
                  m_objectsById.remove(id);
              } else {
                  m_objectsListsById.remove(id);
              }
          }
      }
  }
  