variableexpression.java

大名鼎鼎的java动态脚本语言。已经通过了sun的认证

/*
 $Id: VariableExpression.java,v 1.14 2006/01/19 00:06:51 blackdrag Exp $

 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.

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 ("Software"), with or without modification, are permitted provided
 that the following conditions are met:

 1. Redistributions of source code must retain copyright
    statements and notices.  Redistributions must also contain a
    copy of this document.

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    following disclaimer in the documentation and/or other
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    products derived from this Software without prior written
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    please contact [e-mail].

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    permission of The Codehaus. "groovy" is a registered
    trademark of The Codehaus.

 5. Due credit should be given to The Codehaus -
    http://groovy.codehaus.org/

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 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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package org.codehaus.groovy.ast.expr;

import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.GroovyCodeVisitor;
import org.codehaus.groovy.ast.Variable;

/**
 * Represents a local variable name, the simplest form of expression. e.g. "foo".
 * 
 * @author <a href="mailto:[e-mail]">James Strachan</a>
 * @version $Revision: 1.14 $
 */
public class VariableExpression extends Expression implements Variable {

    public static final VariableExpression THIS_EXPRESSION = new VariableExpression("this", ClassHelper.DYNAMIC_TYPE);
    public static final VariableExpression SUPER_EXPRESSION = new VariableExpression("super", ClassHelper.DYNAMIC_TYPE);

    private String variable;
    private boolean inStaticContext;
    private boolean isDynamicTyped=false;
    private Variable accessedVariable;
    boolean closureShare=false;

    public Variable getAccessedVariable() {
        return accessedVariable;
    }

    public void setAccessedVariable(Variable origin) {
        this.accessedVariable = origin;
    }

    public VariableExpression(String variable, ClassNode type) {
        this.variable = variable;
        super.setType(ClassHelper.getWrapper(type));
    }
    
    public VariableExpression(String variable) {
        this(variable, ClassHelper.DYNAMIC_TYPE);
    }
    
    public VariableExpression(Variable variable) {
        this(variable.getName(), variable.getType());
        setAccessedVariable(variable);
    }

    public void visit(GroovyCodeVisitor visitor) {
        visitor.visitVariableExpression(this);
    }

    public Expression transformExpression(ExpressionTransformer transformer) {
        return this;
    }

    public String getText() {
        return variable;
    }
    
    public String getName() {
        return variable;
    }

    /**
     * @return true if this variable is dynamically typed
     */
    public String toString() {
        return super.toString() + "[variable: " + variable + (this.isDynamicTyped() ? "" : " type: " + getType()) + "]";
    }

    public Expression getInitialExpression() {
        return null;
    }

    public boolean hasInitialExpression() {
        return false;
    }
    
    public boolean isInStaticContext() {
        if (accessedVariable!=null && accessedVariable!=this) return accessedVariable.isInStaticContext();
        return inStaticContext;
    }
    
    public void setInStaticContext(boolean inStaticContext) {
        this.inStaticContext = inStaticContext;
    }

    public void setType(ClassNode cn){
        super.setType(cn);
        isDynamicTyped |= ClassHelper.DYNAMIC_TYPE==cn;
    }
    
    public boolean isDynamicTyped() {
        return isDynamicTyped;
    }

    public boolean isClosureSharedVariable() {
        if (accessedVariable!=null && accessedVariable!=this) return accessedVariable.isClosureSharedVariable();
        return closureShare;
    }
    
    public void setClosureSharedVariable(boolean inClosure) {
        closureShare = inClosure;        
    }
    
    public ClassNode getType() {
        if (accessedVariable!=null && accessedVariable!=this) return accessedVariable.getType();
        return super.getType();
    }
}