Groovy example source code file (CategoryForIteratorTest.groovy)

This example Groovy source code file (CategoryForIteratorTest.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

categoryforiteratortest, categoryforiteratortest, groovytestcase, iterator, iterator, iteratorcategory, object, object, testiterator, testiterator

The Groovy CategoryForIteratorTest.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 org.codehaus.groovy.runtime

/**
 * Test whether the Invoker includes categories when 
 * trying to find an iterator (via the method iterator())
 */
class CategoryForIteratorTest extends GroovyTestCase {

    def identity = { val -> val }
    def c
    def countCalls = { c = c + 1 }

    void setUp() {
        c = 0
    }

    /*
    * Ensure that without the iterator category a
    * one-element collection is returned that
    * results in one call to the countCalls closure
    */

    void testWithoutIteratorCategory() {
        identity.each countCalls
        assert c == 1
    }
    /*
     * When using the IteratorCategory below we get an
     * iterator that does no iteration. So the count
     * has to be 0
     */

    void testWithIteratorCategory() {
        use(IteratorCategory) {
            c = 0
            identity.each countCalls
            assert c == 0
        }
    }
}

/*
 * The category simply adds an iterator()-method returning
 * the null iterator defined below
 */
class IteratorCategory {
    static Iterator iterator(Closure c) {
        return new TestIterator()
    }
}

/*
 * This iterator returns 0 elements, allowing us to distinguish
 * from the default collection-iterator
 */
class TestIterator implements Iterator {
    public boolean hasNext() { return false }

    public Object next() { return null }

    public void remove() {}
}