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Groovy example source code file (MethodCallExpression.java)

This example Groovy source code file (MethodCallExpression.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

constantexpression, constantexpression, expression, expression, genericstype, metamethod, methodcallexpression, methodnode, no_arguments, string, string, tupleexpression, tupleexpression

The Groovy MethodCallExpression.java source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.codehaus.groovy.ast.expr;

import groovy.lang.MetaMethod;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.GenericsType;
import org.codehaus.groovy.ast.GroovyCodeVisitor;
import org.codehaus.groovy.ast.MethodNode;

/**
 * A method call on an object or class
 * 
 * @author <a href="mailto:james@coredevelopers.net">James Strachan
 * @version $Revision: 21775 $
 */
public class MethodCallExpression extends Expression {

    private Expression objectExpression;
    private Expression method;
    private Expression arguments;
    private boolean spreadSafe = false;
    private boolean safe = false;
    private boolean implicitThis;

    // type spec for generics
    private GenericsType[] genericsTypes = null;
    private boolean usesGenerics = false;

    private MethodNode target;
    
    public static final Expression NO_ARGUMENTS = new TupleExpression();

    /**
     * @deprecated
     */
    public MetaMethod getMetaMethod() {
        return null;
    }

    public MethodCallExpression(Expression objectExpression, String method, Expression arguments) {
        this(objectExpression,new ConstantExpression(method),arguments);
    }
    
    public MethodCallExpression(Expression objectExpression, Expression method, Expression arguments) {
        this.objectExpression = objectExpression;
        this.method = method;
        if (!(arguments instanceof TupleExpression)){
            this.arguments = new TupleExpression(arguments);
        } else {
            this.arguments = arguments;
        }
        //TODO: set correct type here
        // if setting type and a methodcall is the last expression in a method,
        // then the method will return null if the method itself is not void too!
        // (in bytecode after call: aconst_null, areturn)
        this.setType(ClassHelper.DYNAMIC_TYPE);
        this.setImplicitThis(true);
    }

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

    public Expression transformExpression(ExpressionTransformer transformer) {
        MethodCallExpression answer =
            new MethodCallExpression(transformer.transform(objectExpression), transformer.transform(method), transformer.transform(arguments));
        answer.setSafe(safe);
        answer.setSpreadSafe(spreadSafe);
        answer.setImplicitThis(implicitThis);
        answer.setSourcePosition(this);
        answer.setMethodTarget(target);
        return answer;
    }

    public Expression getArguments() {
        return arguments;
    }

    public void setArguments(Expression arguments) {
        if (!(arguments instanceof TupleExpression)){
            this.arguments = new TupleExpression(arguments);
        } else {
            this.arguments = arguments;
        }
    }

    public Expression getMethod() {
        return method;
    }

    public void setMethod(Expression method) {
      this.method = method;
    }

    /**
     * This method returns the method name as String if it is no dynamic
     * calculated method name, but a constant.
     */
    public String getMethodAsString() {
        if (! (method instanceof ConstantExpression)) return null;
        ConstantExpression constant = (ConstantExpression) method;
        return constant.getText();
    }

    public void setObjectExpression(Expression objectExpression) {
      this.objectExpression = objectExpression;
    }

    public Expression getObjectExpression() {
        return objectExpression;
    }

    public String getText() {
        String object = objectExpression.getText();
        String meth = method.getText();
        String args = arguments.getText();
        String spread = spreadSafe ? "*" : "";
        String dereference = safe ? "?" : "";
        return object + spread + dereference + "." + meth + args;
    }

    /**
     * @return is this a safe method call, i.e. if true then if the source object is null
     * then this method call will return null rather than throwing a null pointer exception
     */
    public boolean isSafe() {
        return safe;
    }

    public void setSafe(boolean safe) {
        this.safe = safe;
    }

    public boolean isSpreadSafe() {
        return spreadSafe;
    }

    public void setSpreadSafe(boolean value) {
        spreadSafe = value;
    }

    /**
     * @return true if no object expression was specified otherwise if 
     * some expression was specified for the object on which to evaluate
     * the method then return false
     */
    public boolean isImplicitThis() {
        return implicitThis;
    }

    public void setImplicitThis(boolean implicitThis) {
        this.implicitThis = implicitThis;
    }

    public String toString() {
        return super.toString()
            + "[object: "
            + objectExpression
            + " method: "
            + method
            + " arguments: "
            + arguments
            + "]";
    }

    /**
     * @deprecated
     */
    public void setMetaMethod(MetaMethod mmeth) {
        //this.metaMethod = mmeth;
        //super.setType(ClassHelper.make(mmeth.getReturnType()));
    }

    public GenericsType[] getGenericsTypes() {
        return genericsTypes;
    }

    public void setGenericsTypes(GenericsType[] genericsTypes) {
        usesGenerics = usesGenerics || genericsTypes != null;
        this.genericsTypes = genericsTypes;
    }

    public boolean isUsingGenerics() {
        return usesGenerics;
	}

    /**
     * Sets a method call target for a direct method call. 
     * WARNING: A method call made this way will run outside of the MOP! 
     * @param mn the target as MethodNode, mn==null means no target
     */
    public void setMethodTarget(MethodNode mn) {
        this.target = mn;
        if (mn!=null) {
            setType(target.getReturnType());
        } else {
            setType(ClassHelper.OBJECT_TYPE);
        }
    }
    
    /**
     * @return the target as method node if set
     */
    public MethodNode getMethodTarget() {
        return target;
    }
}

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