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.xni.grammars;
  
  /**
   * <p> This interface specifies how the parser and the application
   * interact with respect to Grammar objects that the application
   * possesses--either by having precompiled them or by having stored them
   * from a previous validation of an instance document.  It makes no
   * assumptions about the kind of Grammar involved, or about how the
   * application's storage mechanism works.</p>
   * <p/>
   * <p>The interaction works as follows:
   * <ul>
   * <li>When a validator considers a document, it is expected to request
   * grammars of the type it can handle from this object using the
   * <code>retrieveInitialGrammarSet</code> method. </li>
   * <li>If it requires a grammar
   * not in this set, it will request it from this Object using the
   * <code>retrieveGrammar</code> method.  </li>
   * <li> After successfully validating an
   * instance, the validator should make any new grammars it has compiled
   * available to this object using the <code>cacheGrammars</code>
   * method; for ease of implementation it may make other Grammars it holds references to as well (i.e.,
   * it may return some grammars that were retrieved from the GrammarPool in earlier operations). </li> </ul> </p>
   *
   * @author Neil Graham, IBM
   * @version $Id: XMLGrammarPool.java 447245 2006-09-18 05:22:10Z mrglavas $
   */
  
  public interface XMLGrammarPool {
  
      // <p>we are trying to make this XMLGrammarPool work for all kinds of
      // grammars, so we have a parameter "grammarType" for each of the
      // methods. </p>
  
      /**
       * <p> retrieve the initial known set of grammars. this method is
       * called by a validator before the validation starts. the application
       * can provide an initial set of grammars available to the current
       * validation attempt. </p>
       *
       * @param grammarType the type of the grammar, from the
       *                    <code>org.apache.xerces.xni.grammars.Grammar</code> interface.
       * @return the set of grammars the validator may put in its "bucket"
       */
      Grammar[] retrieveInitialGrammarSet(String grammarType);
  
      /**
       * <p>return the final set of grammars that the validator ended up
       * with.
       * This method is called after the
       * validation finishes. The application may then choose to cache some
       * of the returned grammars. </p>
       *
       * @param grammarType the type of the grammars being returned;
       * @param grammars    an array containing the set of grammars being
       *                    returned; order is not significant.
       */
      void cacheGrammars(String grammarType, Grammar[] grammars);
  
      /**
       * <p> This method requests that the application retrieve a grammar
       * corresponding to the given GrammarIdentifier from its cache.
       * If it cannot do so it must return null; the parser will then
       * call the EntityResolver.  <strong>An application must not call its
       * EntityResolver itself from this method; this may result in infinite
       * recursions.</strong>
       *
       * @param desc The description of the Grammar being requested.
       * @return the Grammar corresponding to this description or null if
       * no such Grammar is known.
       */
      Grammar retrieveGrammar(XMLGrammarDescription desc);
  
      /**
       * Causes the XMLGrammarPool not to store any grammars when
       * the cacheGrammars(String, Grammar[[]) method is called.
       */
      void lockPool();
  
      /**
       * Allows the XMLGrammarPool to store grammars when its cacheGrammars(String, Grammar[])
       * method is called.  This is the default state of the object.
       */
      void unlockPool();
  
      /**
       * Removes all grammars from the pool.
       */
      void clear();
  } // XMLGrammarPool
  
  