001: /* ====================================================================
002: * Tea - Copyright (c) 1997-2000 Walt Disney Internet Group
003: * ====================================================================
004: * The Tea Software License, Version 1.1
005: *
006: * Copyright (c) 2000 Walt Disney Internet Group. All rights reserved.
007: *
008: * Redistribution and use in source and binary forms, with or without
009: * modification, are permitted provided that the following conditions
010: * are met:
011: *
012: * 1. Redistributions of source code must retain the above copyright
013: * notice, this list of conditions and the following disclaimer.
014: *
015: * 2. Redistributions in binary form must reproduce the above copyright
016: * notice, this list of conditions and the following disclaimer in
017: * the documentation and/or other materials provided with the
018: * distribution.
019: *
020: * 3. The end-user documentation included with the redistribution,
021: * if any, must include the following acknowledgment:
022: * "This product includes software developed by the
023: * Walt Disney Internet Group (http://opensource.go.com/)."
024: * Alternately, this acknowledgment may appear in the software itself,
025: * if and wherever such third-party acknowledgments normally appear.
026: *
027: * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must
028: * not be used to endorse or promote products derived from this
029: * software without prior written permission. For written
030: * permission, please contact opensource@dig.com.
031: *
032: * 5. Products derived from this software may not be called "Tea",
033: * "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet",
034: * "Kettle", "Trove" or "BeanDoc" appear in their name, without prior
035: * written permission of the Walt Disney Internet Group.
036: *
037: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
038: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
039: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
040: * DISCLAIMED. IN NO EVENT SHALL THE WALT DISNEY INTERNET GROUP OR ITS
041: * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
042: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
043: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
044: * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
045: * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
046: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
047: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
048: * ====================================================================
049: *
050: * For more information about Tea, please see http://opensource.go.com/.
051: */
052:
053: package com.go.tea.parsetree;
054:
055: import com.go.tea.compiler.SourceInfo;
056: import com.go.tea.compiler.Token;
057: import com.go.tea.compiler.Type;
058: import java.lang.reflect.Method;
059:
060: /******************************************************************************
061: * A Lookup can access properties on objects. A Bean Introspector is used to
062: * get the available properties from an object. Arrays, Lists and Strings also
063: * have a built-in property named "length". For arrays, the length field is
064: * retrieved, for Lists, the size() method is called, and for Strings, the
065: * length() method is called.
066: *
067: * @author Brian S O'Neill
068: * @version
069: * <!--$$Revision:--> 24 <!-- $-->, <!--$$JustDate:--> 9/07/00 <!-- $-->
070: * @see java.beans.Introspector
071: */
072: public class Lookup extends Expression {
073: private Expression mExpr;
074: private Token mDot;
075: private Name mLookupName;
076: private Method mMethod;
077:
078: public Lookup(SourceInfo info, Expression expr, Token dot,
079: Name lookupName) {
080: super (info);
081:
082: mExpr = expr;
083: mDot = dot;
084: mLookupName = lookupName;
085: }
086:
087: public Object accept(NodeVisitor visitor) {
088: return visitor.visit(this );
089: }
090:
091: public Object clone() {
092: Lookup lookup = (Lookup) super .clone();
093: lookup.mExpr = (Expression) mExpr.clone();
094: return lookup;
095: }
096:
097: public boolean isExceptionPossible() {
098: if (super .isExceptionPossible()) {
099: return true;
100: }
101:
102: if (mExpr != null) {
103: if (mExpr.isExceptionPossible()) {
104: return true;
105: }
106: Type type = mExpr.getType();
107: if (type != null && type.isNullable()) {
108: return true;
109: }
110: }
111:
112: return mMethod != null;
113: }
114:
115: public Expression getExpression() {
116: return mExpr;
117: }
118:
119: public Token getDot() {
120: return mDot;
121: }
122:
123: public Name getLookupName() {
124: return mLookupName;
125: }
126:
127: /**
128: * Returns the method to invoke in order to perform the lookup. This is
129: * filled in by the type checker. If the lookup name is "length" and
130: * the expression type is an array, the read method is null. A code
131: * generator must still be able to get the length of the array.
132: */
133: public Method getReadMethod() {
134: return mMethod;
135: }
136:
137: public void setExpression(Expression expr) {
138: mExpr = expr;
139: }
140:
141: public void setReadMethod(Method m) {
142: mMethod = m;
143: }
144: }
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