1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 /* 19 * $Id: XUnresolvedVariable.java 468643 2006-10-28 06:56:03Z minchau $ 20 */ 21 package org.apache.xalan.templates; 22 23 import org.apache.xalan.res.XSLTErrorResources; 24 import org.apache.xalan.transformer.TransformerImpl; 25 import org.apache.xpath.VariableStack; 26 import org.apache.xpath.XPathContext; 27 import org.apache.xpath.objects.XObject; 28 29 /** 30 * An instance of this class holds unto a variable until 31 * it is executed. It is used at this time for global 32 * variables which must (we think) forward reference. 33 */ 34 public class XUnresolvedVariable extends XObject 35 { 36 static final long serialVersionUID = -256779804767950188L; 37 /** The node context for execution. */ 38 transient private int m_context; 39 40 /** The transformer context for execution. */ 41 transient private TransformerImpl m_transformer; 42 43 /** An index to the point in the variable stack where we should 44 * begin variable searches for evaluation of expressions. 45 * This is -1 if m_isTopLevel is false. 46 **/ 47 transient private int m_varStackPos = -1; 48 49 /** An index into the variable stack where the variable context 50 * ends, i.e. at the point we should terminate the search. 51 **/ 52 transient private int m_varStackContext; 53 54 /** true if this variable or parameter is a global. 55 * @serial */ 56 private boolean m_isGlobal; 57 58 /** true if this variable or parameter is not currently being evaluated. */ 59 transient private boolean m_doneEval = true; 60 61 /** 62 * Create an XUnresolvedVariable, that may be executed at a later time. 63 * This is primarily used so that forward referencing works with 64 * global variables. An XUnresolvedVariable is initially pushed 65 * into the global variable stack, and then replaced with the real 66 * thing when it is accessed. 67 * 68 * @param obj Must be a non-null reference to an ElemVariable. 69 * @param sourceNode The node context for execution. 70 * @param transformer The transformer execution context. 71 * @param varStackPos An index to the point in the variable stack where we should 72 * begin variable searches for evaluation of expressions. 73 * @param varStackContext An index into the variable stack where the variable context 74 * ends, i.e. at the point we should terminate the search. 75 * @param isGlobal true if this is a global variable. 76 */ 77 public XUnresolvedVariable(ElemVariable obj, int sourceNode, 78 TransformerImpl transformer, 79 int varStackPos, int varStackContext, 80 boolean isGlobal) 81 { 82 super(obj); 83 m_context = sourceNode; 84 m_transformer = transformer; 85 86 // For globals, this value will have to be updated once we 87 // have determined how many global variables have been pushed. 88 m_varStackPos = varStackPos; 89 90 // For globals, this should zero. 91 m_varStackContext = varStackContext; 92 93 m_isGlobal = isGlobal; 94 } 95 96 /** 97 * For support of literal objects in xpaths. 98 * 99 * @param xctxt The XPath execution context. 100 * 101 * @return This object. 102 * 103 * @throws javax.xml.transform.TransformerException 104 */ 105 public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException 106 { 107 if (!m_doneEval) 108 { 109 this.m_transformer.getMsgMgr().error 110 (xctxt.getSAXLocator(), XSLTErrorResources.ER_REFERENCING_ITSELF, 111 new Object[]{((ElemVariable)this.object()).getName().getLocalName()}); 112 } 113 VariableStack vars = xctxt.getVarStack(); 114 115 // These three statements need to be combined into one operation. 116 int currentFrame = vars.getStackFrame(); 117 //// vars.setStackFrame(m_varStackPos); 118 119 120 ElemVariable velem = (ElemVariable)m_obj; 121 try 122 { 123 m_doneEval = false; 124 if(-1 != velem.m_frameSize) 125 vars.link(velem.m_frameSize); 126 XObject var = velem.getValue(m_transformer, m_context); 127 m_doneEval = true; 128 return var; 129 } 130 finally 131 { 132 // These two statements need to be combined into one operation. 133 // vars.setStackFrame(currentFrame); 134 135 if(-1 != velem.m_frameSize) 136 vars.unlink(currentFrame); 137 } 138 } 139 140 /** 141 * Set an index to the point in the variable stack where we should 142 * begin variable searches for evaluation of expressions. 143 * This is -1 if m_isTopLevel is false. 144 * 145 * @param top A valid value that specifies where in the variable 146 * stack the search should begin. 147 */ 148 public void setVarStackPos(int top) 149 { 150 m_varStackPos = top; 151 } 152 153 /** 154 * Set an index into the variable stack where the variable context 155 * ends, i.e. at the point we should terminate the search. 156 * 157 * @param bottom The point at which the search should terminate, normally 158 * zero for global variables. 159 */ 160 public void setVarStackContext(int bottom) 161 { 162 m_varStackContext = bottom; 163 } 164 165 /** 166 * Tell what kind of class this is. 167 * 168 * @return CLASS_UNRESOLVEDVARIABLE 169 */ 170 public int getType() 171 { 172 return CLASS_UNRESOLVEDVARIABLE; 173 } 174 175 /** 176 * Given a request type, return the equivalent string. 177 * For diagnostic purposes. 178 * 179 * @return An informational string. 180 */ 181 public String getTypeString() 182 { 183 return "XUnresolvedVariable (" + object().getClass().getName() + ")"; 184 } 185 186 187 } 188
