code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  package org.apache.xml.dtm.ref;
  
  import org.apache.xml.dtm.DTM;
  
  /**
   * This is a default implementation of a table that manages mappings from
   * expanded names to expandedNameIDs.
   *
   * %OPT% The performance of the getExpandedTypeID() method is very important 
   * to DTM building. To get the best performance out of this class, we implement
   * a simple hash algorithm directly into this class, instead of using the
   * inefficient java.util.Hashtable. The code for the get and put operations
   * are combined in getExpandedTypeID() method to share the same hash calculation
   * code. We only need to implement the rehash() interface which is used to
   * expand the hash table.
   */
  public class ExpandedNameTable
  {
  
    /** Array of extended types for this document   */
    private ExtendedType[] m_extendedTypes;
  
    /** The initial size of the m_extendedTypes array */
    private static int m_initialSize = 128;
    
    /** Next available extended type   */
    // %REVIEW% Since this is (should be) always equal 
    // to the length of m_extendedTypes, do we need this? 
    private int m_nextType;
  
    // These are all the types prerotated, for caller convenience.
    public static final int ELEMENT = ((int)DTM.ELEMENT_NODE) ;
    public static final int ATTRIBUTE = ((int)DTM.ATTRIBUTE_NODE) ;
    public static final int TEXT = ((int)DTM.TEXT_NODE) ;
    public static final int CDATA_SECTION = ((int)DTM.CDATA_SECTION_NODE) ;
    public static final int ENTITY_REFERENCE = ((int)DTM.ENTITY_REFERENCE_NODE) ;
    public static final int ENTITY = ((int)DTM.ENTITY_NODE) ;
    public static final int PROCESSING_INSTRUCTION = ((int)DTM.PROCESSING_INSTRUCTION_NODE) ;
    public static final int COMMENT = ((int)DTM.COMMENT_NODE) ;
    public static final int DOCUMENT = ((int)DTM.DOCUMENT_NODE) ;
    public static final int DOCUMENT_TYPE = ((int)DTM.DOCUMENT_TYPE_NODE) ;
    public static final int DOCUMENT_FRAGMENT =((int)DTM.DOCUMENT_FRAGMENT_NODE) ;
    public static final int NOTATION = ((int)DTM.NOTATION_NODE) ;
    public static final int NAMESPACE = ((int)DTM.NAMESPACE_NODE) ;
  
    /** Workspace for lookup. NOT THREAD SAFE!
     * */
    ExtendedType hashET = new ExtendedType(-1, "", "");
  
    /** The array to store the default extended types. */
    private static ExtendedType[] m_defaultExtendedTypes;
  
    /**
     * The default load factor of the Hashtable.
     * This is used to calcualte the threshold.
     */
    private static float m_loadFactor = 0.75f;
      
    /**
     * The initial capacity of the hash table. Use a bigger number
     * to avoid the cost of expanding the table.
     */ 
    private static int m_initialCapacity = 203;
    
    /**
     * The capacity of the hash table, i.e. the size of the
     * internal HashEntry array.
     */ 
    private int m_capacity;
    
    /** 
     * The threshold of the hash table, which is equal to capacity * loadFactor.
     * If the number of entries in the hash table is bigger than the threshold,
     * the hash table needs to be expanded.
     */
    private int m_threshold;
    
    /**
     * The internal array to store the hash entries.
     * Each array member is a slot for a hash bucket.
     */
    private HashEntry[] m_table;
  
    /**
     * Init default values
     */
    static {
      m_defaultExtendedTypes = new ExtendedType[DTM.NTYPES];
  
      for (int i = 0; i < DTM.NTYPES; i++)
      {
        m_defaultExtendedTypes[i] = new ExtendedType(i, "", "");
      }
    }
  
    /**
     * Create an expanded name table.
     */
    public ExpandedNameTable()
    {
      m_capacity = m_initialCapacity;
      m_threshold = (int)(m_capacity * m_loadFactor);
      m_table = new HashEntry[m_capacity];
      
      initExtendedTypes();
    }
  
  
    /**
     *  Initialize the vector of extended types with the
     *  basic DOM node types.
     */
    private void initExtendedTypes()
    {    
      m_extendedTypes = new ExtendedType[m_initialSize];
      for (int i = 0; i < DTM.NTYPES; i++) {
          m_extendedTypes[i] = m_defaultExtendedTypes[i];
          m_table[i] = new HashEntry(m_defaultExtendedTypes[i], i, i, null);
      }
      
      m_nextType = DTM.NTYPES;
    }
  
    /**
     * Given an expanded name represented by namespace, local name and node type,
     * return an ID.  If the expanded-name does not exist in the internal tables,
     * the entry will be created, and the ID will be returned.  Any additional 
     * nodes that are created that have this expanded name will use this ID.
     *
     * @param namespace The namespace
     * @param localName The local name
     * @param type The node type
     *
     * @return the expanded-name id of the node.
     */
    public int getExpandedTypeID(String namespace, String localName, int type)
    {
      return getExpandedTypeID(namespace, localName, type, false);
    }
    
    /**
     * Given an expanded name represented by namespace, local name and node type,
     * return an ID.  If the expanded-name does not exist in the internal tables,
     * the entry will be created, and the ID will be returned.  Any additional 
     * nodes that are created that have this expanded name will use this ID.
     * <p>
     * If searchOnly is true, we will return -1 if the name is not found in the 
     * table, otherwise the name is added to the table and the expanded name id
     * of the new entry is returned.
     *
     * @param namespace The namespace
     * @param localName The local name
     * @param type The node type
     * @param searchOnly If it is true, we will only search for the expanded name.
     * -1 is return is the name is not found.
     *
     * @return the expanded-name id of the node.
     */
    public int getExpandedTypeID(String namespace, String localName, int type, boolean searchOnly)
    {
      if (null == namespace)
        namespace = "";
      if (null == localName)
        localName = "";
      
      // Calculate the hash code
      int hash = type + namespace.hashCode() + localName.hashCode();
      
      // Redefine the hashET object to represent the new expanded name.
      hashET.redefine(type, namespace, localName, hash);
      
      // Calculate the index into the HashEntry table.
      int index = hash % m_capacity;
      if (index < 0)
        index = -index;
  
      // Look up the expanded name in the hash table. Return the id if
      // the expanded name is already in the hash table.
      for (HashEntry e = m_table[index]; e != null; e = e.next)
      {
        if (e.hash == hash && e.key.equals(hashET))
          return e.value;
      }
      
      if (searchOnly)
      {
        return DTM.NULL;
      }
  
      // Expand the internal HashEntry array if necessary.
      if (m_nextType > m_threshold) {
        rehash();
        index = hash % m_capacity;
        if (index < 0)
          index = -index;
      }
      
      // Create a new ExtendedType object
      ExtendedType newET = new ExtendedType(type, namespace, localName, hash);
      
      // Expand the m_extendedTypes array if necessary.
      if (m_extendedTypes.length == m_nextType) {
          ExtendedType[] newArray = new ExtendedType[m_extendedTypes.length * 2];
          System.arraycopy(m_extendedTypes, 0, newArray, 0,
                           m_extendedTypes.length);
          m_extendedTypes = newArray;
      }
      
      m_extendedTypes[m_nextType] = newET;
      
      // Create a new hash entry for the new ExtendedType and put it into 
      // the table.
      HashEntry entry = new HashEntry(newET, m_nextType, hash, m_table[index]);
      m_table[index] = entry;
  
      return m_nextType++;
    }
  
    /**
     * Increases the capacity of and internally reorganizes the hashtable, 
     * in order to accommodate and access its entries more efficiently. 
     * This method is called when the number of keys in the hashtable exceeds
     * this hashtable's capacity and load factor.
     */
    private void rehash()
    {
      int oldCapacity = m_capacity;
      HashEntry[] oldTable = m_table;
        
      int newCapacity = 2 * oldCapacity + 1;
      m_capacity = newCapacity;
      m_threshold = (int)(newCapacity * m_loadFactor);
        
      m_table = new HashEntry[newCapacity];
      for (int i = oldCapacity-1; i >=0 ; i--)
      {
        for (HashEntry old = oldTable[i]; old != null; )
        {
          HashEntry e = old;
          old = old.next;
            
          int newIndex = e.hash % newCapacity;
          if (newIndex < 0)
            newIndex = -newIndex;
            
          e.next = m_table[newIndex];
          m_table[newIndex] = e;
        }
      }
    }
  
    /**
     * Given a type, return an expanded name ID.Any additional nodes that are
     * created that have this expanded name will use this ID.
     *
     * @return the expanded-name id of the node.
     */
    public int getExpandedTypeID(int type)
    {
      return type;
    }
  
    /**
     * Given an expanded-name ID, return the local name part.
     *
     * @param ExpandedNameID an ID that represents an expanded-name.
     * @return String Local name of this node, or null if the node has no name.
     */
    public String getLocalName(int ExpandedNameID)
    {
      return m_extendedTypes[ExpandedNameID].getLocalName();
    }
  
    /**
     * Given an expanded-name ID, return the local name ID.
     *
     * @param ExpandedNameID an ID that represents an expanded-name.
     * @return The id of this local name.
     */
    public final int getLocalNameID(int ExpandedNameID)
    {
      // ExtendedType etype = m_extendedTypes[ExpandedNameID];
      if (m_extendedTypes[ExpandedNameID].getLocalName().length() == 0)
        return 0;
      else
      return ExpandedNameID;
    }
  
  
    /**
     * Given an expanded-name ID, return the namespace URI part.
     *
     * @param ExpandedNameID an ID that represents an expanded-name.
     * @return String URI value of this node's namespace, or null if no
     * namespace was resolved.
     */
    public String getNamespace(int ExpandedNameID)
    {
      String namespace = m_extendedTypes[ExpandedNameID].getNamespace();
      return (namespace.length() == 0 ? null : namespace);
    }
  
    /**
     * Given an expanded-name ID, return the namespace URI ID.
     *
     * @param ExpandedNameID an ID that represents an expanded-name.
     * @return The id of this namespace.
     */
    public final int getNamespaceID(int ExpandedNameID)
    {
      //ExtendedType etype = m_extendedTypes[ExpandedNameID];
      if (m_extendedTypes[ExpandedNameID].getNamespace().length() == 0)
        return 0;
      else
      return ExpandedNameID;
    }
  
    /**
     * Given an expanded-name ID, return the local name ID.
     *
     * @param ExpandedNameID an ID that represents an expanded-name.
     * @return The id of this local name.
     */
    public final short getType(int ExpandedNameID)
    {
      //ExtendedType etype = m_extendedTypes[ExpandedNameID];
      return (short)m_extendedTypes[ExpandedNameID].getNodeType();
    }
    
    /**
     * Return the size of the ExpandedNameTable
     *
     * @return The size of the ExpandedNameTable
     */
    public int getSize()
    {
      return m_nextType;
    }
    
    /**
     * Return the array of extended types
     *
     * @return The array of extended types
     */
    public ExtendedType[] getExtendedTypes()
    {
      return m_extendedTypes;
    }
  
    /**
     * Inner class which represents a hash table entry.
     * The field next points to the next entry which is hashed into
     * the same bucket in the case of "hash collision".
     */
    private static final class HashEntry
    {
      ExtendedType key;
      int value;
      int hash;
      HashEntry next;
        
      protected HashEntry(ExtendedType key, int value, int hash, HashEntry next)
      {
        this.key = key;
        this.value = value;
        this.hash = hash;
        this.next = next;
      }
    }
    
  }
  