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1
25 package com.sun.el.lang;
26
27 import java.io.StringReader  ;
28 import java.lang.reflect.Method ;
29 import java.util.Map ;
30 import java.util.concurrent.ConcurrentHashMap ;
31
32 import javax.el.ELContext;
33 import javax.el.ELException;
34 import javax.el.FunctionMapper;
35 import javax.el.MethodExpression;
36 import javax.el.ValueExpression;
37 import javax.el.VariableMapper;
38
39 import com.sun.el.MethodExpressionImpl;
40 import com.sun.el.MethodExpressionLiteral;
41 import com.sun.el.ValueExpressionImpl;
42 import com.sun.el.parser.AstCompositeExpression;
43 import com.sun.el.parser.AstDeferredExpression;
44 import com.sun.el.parser.AstDynamicExpression;
45 import com.sun.el.parser.AstFunction;
46 import com.sun.el.parser.AstIdentifier;
47 import com.sun.el.parser.AstLiteralExpression;
48 import com.sun.el.parser.AstValue;
49 import com.sun.el.parser.ELParser;
50 import com.sun.el.parser.Node;
51 import com.sun.el.parser.NodeVisitor;
52 import com.sun.el.parser.ParseException;
53 import com.sun.el.util.MessageFactory;
54
55
59 public final class ExpressionBuilder implements NodeVisitor {
60
61 private static final int SIZE = 5000;
62 private static final Map cache = new ConcurrentHashMap (SIZE);
63 private static final Map cache2 = new ConcurrentHashMap (SIZE);
64
65 private FunctionMapper fnMapper;
66
67 private VariableMapper varMapper;
68
69 private String expression;
70
71
74 public ExpressionBuilder(String expression, ELContext ctx)
75 throws ELException {
76 this.expression = expression;
77
78 FunctionMapper ctxFn = ctx.getFunctionMapper();
79 VariableMapper ctxVar = ctx.getVariableMapper();
80
81 if (ctxFn != null) {
82 this.fnMapper = new FunctionMapperFactory(ctxFn);
83 }
84 if (ctxVar != null) {
85 this.varMapper = new VariableMapperFactory(ctxVar);
86 }
87 }
88
89 public final static Node createNode(String expr) throws ELException {
90 Node n = createNodeInternal(expr);
91 return n;
92 }
93
94 private final static Node createNodeInternal(String expr)
95 throws ELException {
96 if (expr == null) {
97 throw new ELException(MessageFactory.get("error.null"));
98 }
99
100 Node n = (Node) cache.get(expr);
101 if (n == null && (n = (Node) cache2.get(expr)) == null) {
102 try {
103 n = (new ELParser(new StringReader (expr)))
104 .CompositeExpression();
105
106 if (n instanceof AstCompositeExpression) {
108 int numChildren = n.jjtGetNumChildren();
109 if (numChildren == 1) {
110 n = n.jjtGetChild(0);
111 } else {
112 Class type = null;
113 Node child = null;
114 for (int i = 0; i < numChildren; i++) {
115 child = n.jjtGetChild(i);
116 if (child instanceof AstLiteralExpression)
117 continue;
118 if (type == null)
119 type = child.getClass();
120 else {
121 if (!type.equals(child.getClass())) {
122 throw new ELException(MessageFactory.get(
123 "error.mixed", expr));
124 }
125 }
126 }
127 }
128 }
129 if (n instanceof AstDeferredExpression
130 || n instanceof AstDynamicExpression) {
131 n = n.jjtGetChild(0);
132 }
133 if (cache.size() > SIZE) {
134 cache2.clear();
135 cache2.putAll(cache);
136 cache.clear();
137 }
138 cache.put(expr, n);
139 } catch (ParseException pe) {
140 throw new ELException("Error Parsing: " + expr, pe);
141 }
142 }
143 return n;
144 }
145
146 private void prepare(Node node) throws ELException {
147 node.accept(this);
148 if (this.fnMapper instanceof FunctionMapperFactory) {
149 this.fnMapper = ((FunctionMapperFactory) this.fnMapper).create();
150 }
151 if (this.varMapper instanceof VariableMapperFactory) {
152 this.varMapper = ((VariableMapperFactory) this.varMapper).create();
153 }
154 }
155
156 private Node build() throws ELException {
157 Node n = createNodeInternal(this.expression);
158 this.prepare(n);
159 if (n instanceof AstDeferredExpression
160 || n instanceof AstDynamicExpression) {
161 n = n.jjtGetChild(0);
162 }
163 return n;
164 }
165
166
171 public void visit(Node node) throws ELException {
172 if (node instanceof AstFunction) {
173
174 AstFunction funcNode = (AstFunction) node;
175
176 if (this.fnMapper == null) {
177 throw new ELException(MessageFactory.get("error.fnMapper.null"));
178 }
179 Method m = fnMapper.resolveFunction(funcNode.getPrefix(), funcNode
180 .getLocalName());
181 if (m == null) {
182 throw new ELException(MessageFactory.get(
183 "error.fnMapper.method", funcNode.getOutputName()));
184 }
185 int pcnt = m.getParameterTypes().length;
186 if (node.jjtGetNumChildren() != pcnt) {
187 throw new ELException(MessageFactory.get(
188 "error.fnMapper.paramcount", funcNode.getOutputName(),
189 "" + pcnt, "" + node.jjtGetNumChildren()));
190 }
191 } else if (node instanceof AstIdentifier && this.varMapper != null) {
192 String variable = ((AstIdentifier) node).getImage();
193
194 this.varMapper.resolveVariable(variable);
196 }
197 }
198
199 public ValueExpression createValueExpression(Class expectedType)
200 throws ELException {
201 Node n = this.build();
202 return new ValueExpressionImpl(this.expression, n, this.fnMapper,
203 this.varMapper, expectedType);
204 }
205
206 public MethodExpression createMethodExpression(Class expectedReturnType,
207 Class [] expectedParamTypes) throws ELException {
208 Node n = this.build();
209 if (n instanceof AstValue || n instanceof AstIdentifier) {
210 return new MethodExpressionImpl(expression, n,
211 this.fnMapper, this.varMapper, expectedReturnType,
212 expectedParamTypes);
213 } else if (n instanceof AstLiteralExpression) {
214 return new MethodExpressionLiteral(expression, expectedReturnType,
215 expectedParamTypes);
216 } else {
217 throw new ELException("Not a Valid Method Expression: "
218 + expression);
219 }
220 }
221 }
222 |
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