1 /*
   2  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.xml.internal.rngom.digested;
  27 
  28 import java.util.HashMap;
  29 import java.util.Iterator;
  30 import java.util.Map;
  31 
  32 /**
  33  * <grammar> pattern, which is a collection of named patterns.
  34  *
  35  * @author Kohsuke Kawaguchi (kk@kohsuke.org)
  36  */
  37 public class DGrammarPattern extends DPattern implements Iterable<DDefine> {
  38     private final Map<String,DDefine> patterns = new HashMap<String,DDefine>();
  39 
  40     DPattern start;
  41 
  42     /**
  43      * Gets the start pattern.
  44      */
  45     public DPattern getStart() {
  46         return start;
  47     }
  48 
  49     /**
  50      * Gets the named pattern by its name.
  51      *
  52      * @return
  53      *      null if not found.
  54      */
  55     public DDefine get( String name ) {
  56         return patterns.get(name);
  57     }
  58 
  59     DDefine getOrAdd( String name ) {
  60         if(patterns.containsKey(name)) {
  61             return get(name);
  62         } else {
  63             DDefine d = new DDefine(name);
  64             patterns.put(name,d);
  65             return d;
  66         }
  67     }
  68 
  69     /**
  70      * Iterates all the {@link DDefine}s in this grammar.
  71      */
  72     public Iterator<DDefine> iterator() {
  73         return patterns.values().iterator();
  74     }
  75 
  76     public boolean isNullable() {
  77         return start.isNullable();
  78     }
  79 
  80     public <V> V accept( DPatternVisitor<V> visitor ) {
  81         return visitor.onGrammar(this);
  82     }
  83 }