[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | package org.apache.hadoop.util; |
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| 19 | |
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| 20 | import java.util.ArrayList; |
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| 21 | import java.util.Arrays; |
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| 22 | import java.util.List; |
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| 23 | import java.util.Map; |
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| 24 | import java.util.NavigableMap; |
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| 25 | import java.util.TreeMap; |
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| 26 | |
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| 27 | public class TestCyclicIteration extends junit.framework.TestCase { |
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| 28 | public void testCyclicIteration() throws Exception { |
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| 29 | for(int n = 0; n < 5; n++) { |
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| 30 | checkCyclicIteration(n); |
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| 31 | } |
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| 32 | } |
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| 33 | |
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| 34 | private static void checkCyclicIteration(int numOfElements) { |
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| 35 | //create a tree map |
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| 36 | final NavigableMap<Integer, Integer> map = new TreeMap<Integer, Integer>(); |
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| 37 | final Integer[] integers = new Integer[numOfElements]; |
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| 38 | for(int i = 0; i < integers.length; i++) { |
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| 39 | integers[i] = 2*i; |
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| 40 | map.put(integers[i], integers[i]); |
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| 41 | } |
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| 42 | System.out.println("\n\nintegers=" + Arrays.asList(integers)); |
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| 43 | System.out.println("map=" + map); |
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| 44 | |
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| 45 | //try starting everywhere |
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| 46 | for(int start = -1; start <= 2*integers.length - 1; start++) { |
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| 47 | //get a cyclic iteration |
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| 48 | final List<Integer> iteration = new ArrayList<Integer>(); |
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| 49 | for(Map.Entry<Integer, Integer> e : new CyclicIteration<Integer, Integer>(map, start)) { |
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| 50 | iteration.add(e.getKey()); |
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| 51 | } |
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| 52 | System.out.println("start=" + start + ", iteration=" + iteration); |
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| 53 | |
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| 54 | //verify results |
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| 55 | for(int i = 0; i < integers.length; i++) { |
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| 56 | final int j = ((start+2)/2 + i)%integers.length; |
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| 57 | assertEquals("i=" + i + ", j=" + j, iteration.get(i), integers[j]); |
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| 58 | } |
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| 59 | } |
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| 60 | } |
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| 61 | } |
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