content: /*
   * 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.
   */
  
  package mf.org.apache.xerces.util;
  
  
  /**
   * Shadowed symbol table.
   * <p/>
   * The table has a reference to the main symbol table and is
   * not allowed to add new symbols to the main symbol table.
   * New symbols are added to the shadow symbol table and are local
   * to the component using this table.
   *
   * @author Andy Clark IBM
   * @version $Id: ShadowedSymbolTable.java 447241 2006-09-18 05:12:57Z mrglavas $
   */
  
  public final class ShadowedSymbolTable
          extends SymbolTable {
  
      //
      // Data
      //
  
      /**
       * Main symbol table.
       */
      protected SymbolTable fSymbolTable;
  
      //
      // Constructors
      //
  
      /**
       * Constructs a shadow of the specified symbol table.
       */
      public ShadowedSymbolTable(SymbolTable symbolTable) {
          fSymbolTable = symbolTable;
      } // <init>(SymbolTable)
  
      //
      // SymbolTable methods
      //
  
      /**
       * Adds the specified symbol to the symbol table and returns a
       * reference to the unique symbol. If the symbol already exists,
       * the previous symbol reference is returned instead, in order
       * guarantee that symbol references remain unique.
       *
       * @param symbol The new symbol.
       */
      @Override
      public String addSymbol(String symbol) {
  
          if (fSymbolTable.containsSymbol(symbol)) {
              return fSymbolTable.addSymbol(symbol);
          }
          return super.addSymbol(symbol);
  
      } // addSymbol(String)
  
      /**
       * Adds the specified symbol to the symbol table and returns a
       * reference to the unique symbol. If the symbol already exists,
       * the previous symbol reference is returned instead, in order
       * guarantee that symbol references remain unique.
       *
       * @param buffer The buffer containing the new symbol.
       * @param offset The offset into the buffer of the new symbol.
       * @param length The length of the new symbol in the buffer.
       */
      @Override
      public String addSymbol(char[] buffer, int offset, int length) {
  
          if (fSymbolTable.containsSymbol(buffer, offset, length)) {
              return fSymbolTable.addSymbol(buffer, offset, length);
          }
          return super.addSymbol(buffer, offset, length);
  
      } // addSymbol(char[],int,int):String
  
      /**
       * Returns a hashcode value for the specified symbol. The value
       * returned by this method must be identical to the value returned
       * by the <code>hash(char[],int,int)</code> method when called
       * with the character array that comprises the symbol string.
       *
       * @param symbol The symbol to hash.
       */
      @Override
      public int hash(String symbol) {
          return fSymbolTable.hash(symbol);
      } // hash(String):int
  
      /**
       * Returns a hashcode value for the specified symbol information.
       * The value returned by this method must be identical to the value
       * returned by the <code>hash(String)</code> method when called
       * with the string object created from the symbol information.
       *
       * @param buffer The character buffer containing the symbol.
       * @param offset The offset into the character buffer of the start
       *               of the symbol.
       * @param length The length of the symbol.
       */
      @Override
      public int hash(char[] buffer, int offset, int length) {
          return fSymbolTable.hash(buffer, offset, length);
      } // hash(char[],int,int):int
  
  } // class ShadowedSymbolTable
  