/*
* Copyright 2012-2014 headius.
*
* 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 com.headius.invokebinder.transform;
import com.headius.invokebinder.InvalidTransformException;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodType;
/**
* An array-spreading transform.
*
* Equivalent call: MethodHandles.spreadInvoker(MethodType, int).bindTo(MethodHandle)
*/
public class Spread extends Transform {
private final MethodType source;
private final Class[] spreadTypes;
public Spread(MethodType source, Class... spreadTypes) {
this.source = source;
this.spreadTypes = spreadTypes;
}
public MethodHandle up(MethodHandle target) {
return target.asSpreader(source.parameterType(source.parameterCount() - 1), spreadTypes.length);
}
public MethodType down(MethodType type) {
int last = source.parameterCount() - 1;
if (!source.parameterArray()[last].isArray()) {
throw new InvalidTransformException("trailing argument is not []: " + source);
}
type = type.dropParameterTypes(last, last + 1);
return type.appendParameterTypes(spreadTypes);
}
public String toString() {
return "spread " + source + " to " + down(source);
}
}