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Groovy example source code file (ClosureComposeTest.groovy)

This example Groovy source code file (ClosureComposeTest.groovy) 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

character, character, closurecomposetest, closurecomposetest, composetesthelper, composetesthelper, f, groovytestcase, integer, integer

The Groovy ClosureComposeTest.groovy source code

/*
 * Copyright 2003-2010 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 groovy

/**
 * @author Paul King
 */
class ClosureComposeTest extends GroovyTestCase {

    void testComposeMultiply() {
        def twice = { a -> a * 2 }
        def thrice = { a -> a * 3 }
        def times6 = twice >> thrice
        assert times6(3) == 18
    }

    void testReverseComposeAndCallShortcut() {
        def twice = { a -> a * 2 }
        def thrice = { a -> a * 3 }
        assert twice << thrice << 3 == 18
    }

    void testComposeAndLonghand() {
        def twice = { a -> a * 2 }
        def inc = { b -> b + 1 }
        def f = inc >> twice
        def g = { x -> twice(inc(x)) }
        assert f(10) == 22
        assert g(10) == 22
    }

    // GROOVY-4512
    void testClosureCompositionInstance() {
        def inst = new ComposeTestHelper()
        assert inst.composedA.call() == 42
        assert inst.composedA() == 42
        assert inst.composedB.call(3) == 122
        assert inst.composedB(3) == 122
    }

    void testComposeWithMethodClosure() {
        def s2c = { it.chars[0] }
        def p = Integer.&toHexString >> s2c >> Character.&toUpperCase
        assert p(15) == 'F'
    }

    void testComposeWithMultipleArgs() {
        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]
    }

    void testReverseCompositionWithMultipleArgs() {
        def multiply = { a, b -> a * b }
        def identity = { a -> [a, a] }
        def sq = multiply << identity
        assert (1..5).collect { sq(it) } == [1, 4, 9, 16, 25]
    }

    void testComposeWithCurriedClosures() {
        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
    }

    class ComposeTestHelper {
        def closure1 = { 40 }
        def closure2 = { it * 40 }
        def closure3 = { it + 2 }
        def composedA = closure1 >> closure3
        def composedB = closure2 >> closure3
    }
}

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