001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the "License");
007 * you may not use this file except in compliance with the License.
008 * You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 /*
019 * $Id: StringType.java 468649 2006-10-28 07:00:55Z minchau $
020 */
021
022 package org.apache.xalan.xsltc.compiler.util;
023
024 import org.apache.bcel.generic.ALOAD;
025 import org.apache.bcel.generic.ASTORE;
026 import org.apache.bcel.generic.BranchHandle;
027 import org.apache.bcel.generic.ConstantPoolGen;
028 import org.apache.bcel.generic.GOTO;
029 import org.apache.bcel.generic.IFEQ;
030 import org.apache.bcel.generic.IFNONNULL;
031 import org.apache.bcel.generic.INVOKESTATIC;
032 import org.apache.bcel.generic.INVOKEVIRTUAL;
033 import org.apache.bcel.generic.Instruction;
034 import org.apache.bcel.generic.InstructionList;
035 import org.apache.bcel.generic.PUSH;
036 import org.apache.xalan.xsltc.compiler.Constants;
037 import org.apache.xalan.xsltc.compiler.FlowList;
038
039 /**
040 * @author Jacek Ambroziak
041 * @author Santiago Pericas-Geertsen
042 */
043 public class StringType extends Type {
044 protected StringType() {}
045
046 public String toString() {
047 return "string";
048 }
049
050 public boolean identicalTo(Type other) {
051 return this == other;
052 }
053
054 public String toSignature() {
055 return "Ljava/lang/String;";
056 }
057
058 public boolean isSimple() {
059 return true;
060 }
061
062 public org.apache.bcel.generic.Type toJCType() {
063 return org.apache.bcel.generic.Type.STRING;
064 }
065
066 /**
067 * Translates a string into an object of internal type <code>type</code>.
068 * The translation to int is undefined since strings are always converted
069 * to reals in arithmetic expressions.
070 *
071 * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
072 */
073 public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
074 Type type) {
075 if (type == Type.Boolean) {
076 translateTo(classGen, methodGen, (BooleanType) type);
077 }
078 else if (type == Type.Real) {
079 translateTo(classGen, methodGen, (RealType) type);
080 }
081 else if (type == Type.Reference) {
082 translateTo(classGen, methodGen, (ReferenceType) type);
083 }
084 else {
085 ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
086 toString(), type.toString());
087 classGen.getParser().reportError(Constants.FATAL, err);
088 }
089 }
090
091 /**
092 * Translates a string into a synthesized boolean.
093 *
094 * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
095 */
096 public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
097 BooleanType type) {
098 final InstructionList il = methodGen.getInstructionList();
099 FlowList falsel = translateToDesynthesized(classGen, methodGen, type);
100 il.append(ICONST_1);
101 final BranchHandle truec = il.append(new GOTO(null));
102 falsel.backPatch(il.append(ICONST_0));
103 truec.setTarget(il.append(NOP));
104 }
105
106 /**
107 * Translates a string into a real by calling stringToReal() from the
108 * basis library.
109 *
110 * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
111 */
112 public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
113 RealType type) {
114 final ConstantPoolGen cpg = classGen.getConstantPool();
115 final InstructionList il = methodGen.getInstructionList();
116 il.append(new INVOKESTATIC(cpg.addMethodref(BASIS_LIBRARY_CLASS,
117 STRING_TO_REAL,
118 STRING_TO_REAL_SIG)));
119 }
120
121 /**
122 * Translates a string into a non-synthesized boolean. It does not push a
123 * 0 or a 1 but instead returns branchhandle list to be appended to the
124 * false list.
125 *
126 * @see org.apache.xalan.xsltc.compiler.util.Type#translateToDesynthesized
127 */
128 public FlowList translateToDesynthesized(ClassGenerator classGen,
129 MethodGenerator methodGen,
130 BooleanType type) {
131 final ConstantPoolGen cpg = classGen.getConstantPool();
132 final InstructionList il = methodGen.getInstructionList();
133
134 il.append(new INVOKEVIRTUAL(cpg.addMethodref(STRING_CLASS,
135 "length", "()I")));
136 return new FlowList(il.append(new IFEQ(null)));
137 }
138
139 /**
140 * Expects a string on the stack and pushes a boxed string.
141 * Strings are already boxed so the translation is just a NOP.
142 *
143 * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
144 */
145 public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
146 ReferenceType type) {
147 methodGen.getInstructionList().append(NOP);
148 }
149
150 /**
151 * Translates a internal string into an external (Java) string.
152 *
153 * @see org.apache.xalan.xsltc.compiler.util.Type#translateFrom
154 */
155 public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
156 Class clazz)
157 {
158 // Is String <: clazz? I.e. clazz in { String, Object }
159 if (clazz.isAssignableFrom(java.lang.String.class)) {
160 methodGen.getInstructionList().append(NOP);
161 }
162 else {
163 ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
164 toString(), clazz.getName());
165 classGen.getParser().reportError(Constants.FATAL, err);
166 }
167 }
168
169 /**
170 * Translates an external (primitive) Java type into a string.
171 *
172 * @see org.apache.xalan.xsltc.compiler.util.Type#translateFrom
173 */
174 public void translateFrom(ClassGenerator classGen,
175 MethodGenerator methodGen, Class clazz)
176 {
177 final ConstantPoolGen cpg = classGen.getConstantPool();
178 final InstructionList il = methodGen.getInstructionList();
179
180 if (clazz.getName().equals("java.lang.String")) {
181 // same internal representation, convert null to ""
182 il.append(DUP);
183 final BranchHandle ifNonNull = il.append(new IFNONNULL(null));
184 il.append(POP);
185 il.append(new PUSH(cpg, ""));
186 ifNonNull.setTarget(il.append(NOP));
187 }
188 else {
189 ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
190 toString(), clazz.getName());
191 classGen.getParser().reportError(Constants.FATAL, err);
192 }
193 }
194
195 /**
196 * Translates an object of this type to its boxed representation.
197 */
198 public void translateBox(ClassGenerator classGen,
199 MethodGenerator methodGen) {
200 translateTo(classGen, methodGen, Type.Reference);
201 }
202
203 /**
204 * Translates an object of this type to its unboxed representation.
205 */
206 public void translateUnBox(ClassGenerator classGen,
207 MethodGenerator methodGen) {
208 methodGen.getInstructionList().append(NOP);
209 }
210
211 /**
212 * Returns the class name of an internal type's external representation.
213 */
214 public String getClassName() {
215 return(STRING_CLASS);
216 }
217
218
219 public Instruction LOAD(int slot) {
220 return new ALOAD(slot);
221 }
222
223 public Instruction STORE(int slot) {
224 return new ASTORE(slot);
225 }
226 }