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Groovy: A powerful, dynamic language for the JVM
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.codehaus.groovy.ast.GroovyCodeVisitor;
/**
* Represents a short ternary expression x ?: y, which is equal
* to
*
* def truePart = x
* def booleanPart = truePart as boolean
* booleanPart? truePart : y
*
* Even if x is no atomic expression, x will be evaluated only
* once. Example:
*
* class Foo {
* def index=0
* def getX(){ index++; return index }
* }
* def foo = new Foo()
* def result = foo.x ?: "false case"
* assert foo.index == 1
* assert result == 1
*
*
* @author Jochen Theodorou
* @since 1.5
*/
public class ElvisOperatorExpression extends TernaryExpression {
public ElvisOperatorExpression(Expression base, Expression falseExpression) {
super(getBool(base), base, falseExpression);
}
private static BooleanExpression getBool(Expression base) {
BooleanExpression be = new BooleanExpression(base);
be.setSourcePosition(base);
return be;
}
public void visit(GroovyCodeVisitor visitor) {
visitor.visitShortTernaryExpression(this);
}
public Expression transformExpression(ExpressionTransformer transformer) {
Expression ret = new ElvisOperatorExpression(
transformer.transform(getTrueExpression()),
transformer.transform(getFalseExpression()));
ret.setSourcePosition(this);
ret.copyNodeMetaData(this);
return ret;
}
}