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/*
 *  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;

import groovy.lang.Closure;

import java.util.List;

/**
 * A wrapper for Closure to support composition.
 * Normally used only internally through the rightShift() and
 * leftShift() methods on Closure.
 * 

* Typical usages: *

 * def twice = { a -> a * 2 }
 * def inc = { b -> b + 1 }
 * def f = { x -> twice(inc(x)) } // longhand
 * def g = inc >> twice
 * def h = twice << inc
 * assert f(10) == 22
 * assert g(10) == 22
 * assert h(10) == 22
 *
 * def s2c = { it.chars[0] }
 * def p = Integer.&toHexString >> s2c >> Character.&toUpperCase
 * assert p(15) == 'F'
 *
 * def multiply = { a, b -> a * b }
 * def identity = { a -> [a, a] }
 * def sq = identity >> multiply
 * assert (1..5).collect{ sq(it) } == [1, 4, 9, 16, 25]
 *
 * def add3 = { a, b, c -> a + b + c }
 * def add2plus10 = add3.curry(10)
 * def multBoth = { a, b, c -> [a*c, b*c] }
 * def twiceBoth = multBoth.rcurry(2)
 * def twiceBothPlus10 = twiceBoth >> add2plus10
 * assert twiceBothPlus10(5, 10) == 40
 * 
* * @author Paul King */ public final class ComposedClosure extends Closure { private static final long serialVersionUID = 1290542293376731831L; private Closure first; private Closure second; public ComposedClosure(Closure first, Closure second) { super(first.clone()); this.first = (Closure) getOwner(); this.second = (Closure) second.clone(); maximumNumberOfParameters = first.getMaximumNumberOfParameters(); } public void setDelegate(Object delegate) { ((Closure) getOwner()).setDelegate(delegate); second.setDelegate(delegate); } public Object getDelegate() { return ((Closure) getOwner()).getDelegate(); } public void setResolveStrategy(int resolveStrategy) { ((Closure) getOwner()).setResolveStrategy(resolveStrategy); second.setResolveStrategy(resolveStrategy); } public int getResolveStrategy() { return ((Closure) getOwner()).getResolveStrategy(); } public Object clone() { return new ComposedClosure(first, second); } public Class[] getParameterTypes() { return first.getParameterTypes(); } public Object doCall(Object... args) { return call(args); } @Override public V call(Object... args) { Object temp = first.call(args); if (temp instanceof List && second.getParameterTypes().length > 1) temp = ((List) temp).toArray(); return temp instanceof Object[] ? second.call((Object[]) temp) : second.call(temp); } }




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