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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.runtime.callsite;
import org.codehaus.groovy.runtime.ExceptionUtils;
/**
* Helper class for internal use only. This allows to call a given method and
* convert the result to a boolean. It will do this by caching the method call
* as well as the "asBoolean" in {@link CallSiteArray} fashion. "asBoolean" will not be
* called if the result is null or a Boolean. In case of null we return false and
* in case of a Boolean we simply unbox. This logic is designed after the one present
* in {@link org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation#castToBoolean(Object)}. The purpose of
* this class is to avoid the slow "asBoolean" call in that method.
*
* The nature of this class allows a per instance caching instead of a per class
* caching like the normal {@link CallSiteArray} logic.
*
* @author Jochen "blackdrag" Theodorou
*/
public class BooleanReturningMethodInvoker {
private final CallSiteArray csa;
public BooleanReturningMethodInvoker() {
this(null);
}
public BooleanReturningMethodInvoker(String methodName) {
csa = new CallSiteArray(BooleanReturningMethodInvoker.class, new String[]{methodName, "asBoolean"});
}
public boolean invoke(Object receiver, Object... args) {
try {
// make cached call for given method
Object ret = csa.array[0].call(receiver, args);
return convertToBoolean(ret);
} catch (Throwable t) {
// ExceptionUtils is a bytecode generated helper class
// to allow throwing checked exceptions without declaring a throws
ExceptionUtils.sneakyThrow(t);
return false;
}
}
public boolean convertToBoolean(Object arg) {
// handle conversion to boolean
if (arg == null) return false;
if (arg instanceof Boolean) {
return ((Boolean) arg).booleanValue();
}
// it was not null and not boolean, so call asBoolean
try {
arg = csa.array[1].call(arg, CallSiteArray.NOPARAM);
} catch (Throwable t) {
// ExceptionUtils is a bytecode generated helper class
// to allow throwing checked exceptions without declaring a throws
ExceptionUtils.sneakyThrow(t);
}
return ((Boolean) arg).booleanValue();
}
}