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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   /*
6    * Copyright 2001-2004 The Apache Software Foundation.
7    *
8    * Licensed under the Apache License, Version 2.0 (the "License");
9    * you may not use this file except in compliance with the License.
10   * You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  /*
21   * $Id: Fallback.java,v 1.2.4.1 2005/09/01 14:22:25 pvedula Exp $
22   */
23  
24  package com.sun.org.apache.xalan.internal.xsltc.compiler;
25  
26  import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
27  import com.sun.org.apache.bcel.internal.generic.InstructionList;
28  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
29  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
30  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
31  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
32  
33  /**
34   * @author Morten Jorgensen
35   */
36  final class Fallback extends Instruction {
37  
38      private boolean _active = false;
39  
40      /**
41       * This element never produces any data on the stack
42       */
43      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
44          if (_active) {
45              return(typeCheckContents(stable));
46          }
47          else {
48              return Type.Void;
49          }
50      }
51  
52      /**
53       * Activate this fallback element
54       */
55      public void activate() {
56          _active = true;
57      }
58  
59      public String toString() {
60          return("fallback");
61      }
62  
63      /**
64       * Parse contents only if this fallback element is put in place of
65       * some unsupported element or non-XSLTC extension element
66       */
67      public void parseContents(Parser parser) {
68          if (_active) parseChildren(parser);
69      }
70  
71      /**
72       * Translate contents only if this fallback element is put in place of
73       * some unsupported element or non-XSLTC extension element
74       */
75      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
76          final ConstantPoolGen cpg = classGen.getConstantPool();
77          final InstructionList il = methodGen.getInstructionList();
78  
79          if (_active) translateContents(classGen, methodGen);
80      }
81  }