Commons Math example source code file (OpenIntToFieldTest.java)

This example Commons Math source code file (OpenIntToFieldTest.java) 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 - Commons Math tags/keywords

entry, fraction, fraction, fractionconversionexception, hashmap, hashmap, illegalstateexception, map, map, openinttofieldhashmap, openinttofieldhashmap, random, set, testcase, util

The Commons Math OpenIntToFieldTest.java source code

/*
 * 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.apache.commons.math.util;

import java.util.ConcurrentModificationException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Random;
import java.util.Set;
import java.util.Map.Entry;

import org.apache.commons.math.Field;
import org.apache.commons.math.fraction.Fraction;
import org.apache.commons.math.fraction.FractionConversionException;
import org.apache.commons.math.fraction.FractionField;

import junit.framework.TestCase;

public class OpenIntToFieldTest extends TestCase {

    private Map<Integer, Fraction> javaMap = new HashMap();
    private FractionField field = FractionField.getInstance();

    @Override
    protected void setUp() throws Exception {
        javaMap.put(50, new Fraction(100.0));
        javaMap.put(75, new Fraction(75.0));
        javaMap.put(25, new Fraction(500.0));
        javaMap.put(Integer.MAX_VALUE, new Fraction(Integer.MAX_VALUE));
        javaMap.put(0, new Fraction(-1.0));
        javaMap.put(1, new Fraction(0.0));
        javaMap.put(33, new Fraction(-0.1));
        javaMap.put(23234234, new Fraction(-242343.0));
        javaMap.put(23321, new Fraction (Integer.MIN_VALUE));
        javaMap.put(-4444, new Fraction(332.0));
        javaMap.put(-1, new Fraction(-2323.0));
        javaMap.put(Integer.MIN_VALUE, new Fraction(44.0));

        /* Add a few more to cause the table to rehash */
        javaMap.putAll(generate());

    }

    private Map<Integer, Fraction> generate() {
        Map<Integer, Fraction> map = new HashMap();
        Random r = new Random();
        double dd=0;
        for (int i = 0; i < 2000; ++i)
            dd = r.nextDouble();
            try {
                map.put(r.nextInt(), new Fraction(dd));
            } catch (FractionConversionException e) {
                throw new IllegalStateException("Invalid :"+dd, e);
            }
        return map;
    }

    private OpenIntToFieldHashMap<Fraction> createFromJavaMap(Field field) {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field);
        for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            map.put(mapEntry.getKey(), mapEntry.getValue());
        }
        return map;
    }

    public void testPutAndGetWith0ExpectedSize() {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field,0);
        assertPutAndGet(map);
    }

    public void testPutAndGetWithExpectedSize() {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field,500);
        assertPutAndGet(map);
    }

    public void testPutAndGet() {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field);
        assertPutAndGet(map);
    }

    private void assertPutAndGet(OpenIntToFieldHashMap<Fraction> map) {
        assertPutAndGet(map, 0, new HashSet<Integer>());
    }

    private void assertPutAndGet(OpenIntToFieldHashMap<Fraction> map, int mapSize,
            Set<Integer> keysInMap) {
        assertEquals(mapSize, map.size());
        for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            map.put(mapEntry.getKey(), mapEntry.getValue());
            if (!keysInMap.contains(mapEntry.getKey()))
                ++mapSize;
            assertEquals(mapSize, map.size());
            assertEquals(mapEntry.getValue(), map.get(mapEntry.getKey()));
        }
    }

    public void testPutAbsentOnExisting() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        int size = javaMap.size();
        for (Map.Entry<Integer, Fraction> mapEntry : generateAbsent().entrySet()) {
            map.put(mapEntry.getKey(), mapEntry.getValue());
            assertEquals(++size, map.size());
            assertEquals(mapEntry.getValue(), map.get(mapEntry.getKey()));
        }
    }

    public void testPutOnExisting() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            map.put(mapEntry.getKey(), mapEntry.getValue());
            assertEquals(javaMap.size(), map.size());
            assertEquals(mapEntry.getValue(), map.get(mapEntry.getKey()));
        }
    }

    public void testGetAbsent() {
        Map<Integer, Fraction> generated = generateAbsent();
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);

        for (Map.Entry<Integer, Fraction> mapEntry : generated.entrySet())
            assertTrue(field.getZero().equals(map.get(mapEntry.getKey())));
    }

    public void testGetFromEmpty() {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field);
        assertTrue(field.getZero().equals(map.get(5)));
        assertTrue(field.getZero().equals(map.get(0)));
        assertTrue(field.getZero().equals(map.get(50)));
    }

    public void testRemove() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        int mapSize = javaMap.size();
        assertEquals(mapSize, map.size());
        for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            map.remove(mapEntry.getKey());
            assertEquals(--mapSize, map.size());
            assertTrue(field.getZero().equals(map.get(mapEntry.getKey())));
        }

        /* Ensure that put and get still work correctly after removals */
        assertPutAndGet(map);
    }

    /* This time only remove some entries */
    public void testRemove2() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        int mapSize = javaMap.size();
        int count = 0;
        Set<Integer> keysInMap = new HashSet(javaMap.keySet());
        for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            keysInMap.remove(mapEntry.getKey());
            map.remove(mapEntry.getKey());
            assertEquals(--mapSize, map.size());
            assertTrue(field.getZero().equals(map.get(mapEntry.getKey())));
            if (count++ > 5)
                break;
        }

        /* Ensure that put and get still work correctly after removals */
        assertPutAndGet(map, mapSize, keysInMap);
    }

    public void testRemoveFromEmpty() {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field);
        assertTrue(field.getZero().equals(map.remove(50)));
    }

    public void testRemoveAbsent() {
        Map<Integer, Fraction> generated = generateAbsent();

        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        int mapSize = map.size();

        for (Map.Entry<Integer, Fraction> mapEntry : generated.entrySet()) {
            map.remove(mapEntry.getKey());
            assertEquals(mapSize, map.size());
            assertTrue(field.getZero().equals(map.get(mapEntry.getKey())));
        }
    }

    /**
     * Returns a map with at least 100 elements where each element is absent from javaMap.
     */
    private Map<Integer, Fraction> generateAbsent() {
        Map<Integer, Fraction> generated = new HashMap();
        do {
            generated.putAll(generate());
            for (Integer key : javaMap.keySet())
                generated.remove(key);
        } while (generated.size() < 100);
        return generated;
    }

    public void testCopy() {
        OpenIntToFieldHashMap<Fraction> copy =
            new OpenIntToFieldHashMap<Fraction>(createFromJavaMap(field));
        assertEquals(javaMap.size(), copy.size());

        for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet())
            assertEquals(mapEntry.getValue(), copy.get(mapEntry.getKey()));
    }

    public void testContainsKey() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        for (Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            assertTrue(map.containsKey(mapEntry.getKey()));
        }
        for (Map.Entry<Integer, Fraction> mapEntry : generateAbsent().entrySet()) {
            assertFalse(map.containsKey(mapEntry.getKey()));
        }
        for (Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
            int key = mapEntry.getKey();
            assertTrue(map.containsKey(key));
            map.remove(key);
            assertFalse(map.containsKey(key));
        }
    }

    public void testIterator() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        OpenIntToFieldHashMap<Fraction>.Iterator iterator = map.iterator();
        for (int i = 0; i < map.size(); ++i) {
            assertTrue(iterator.hasNext());
            iterator.advance();
            int key = iterator.key();
            assertTrue(map.containsKey(key));
            assertEquals(javaMap.get(key), map.get(key));
            assertEquals(javaMap.get(key), iterator.value());
            assertTrue(javaMap.containsKey(key));
        }
        assertFalse(iterator.hasNext());
        try {
            iterator.advance();
            fail("an exception should have been thrown");
        } catch (NoSuchElementException nsee) {
            // expected
        }
    }

    public void testConcurrentModification() {
        OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
        OpenIntToFieldHashMap<Fraction>.Iterator iterator = map.iterator();
        map.put(3, new Fraction(3));
        try {
            iterator.advance();
            fail("an exception should have been thrown");
        } catch (ConcurrentModificationException cme) {
            // expected
        }
    }

    /**
     * Regression test for a bug in findInsertionIndex where the hashing in the second probing
     * loop was inconsistent with the first causing duplicate keys after the right sequence
     * of puts and removes.
     */
    public void testPutKeysWithCollisions() {
        OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap(field);
        int key1 = -1996012590;
        Fraction value1 = new Fraction(1);
        map.put(key1, value1);
        int key2 = 835099822;
        map.put(key2, value1);
        int key3 = 1008859686;
        map.put(key3, value1);
        assertEquals(value1, map.get(key3));
        assertEquals(3, map.size());

        map.remove(key2);
        Fraction value2 = new Fraction(2);
        map.put(key3, value2);
        assertEquals(value2, map.get(key3));
        assertEquals(2, map.size());
    }

    /**
     * Similar to testPutKeysWithCollisions() but exercises the codepaths in a slightly
     * different manner.
     */
    public void testPutKeysWithCollision2() {
        OpenIntToFieldHashMap<Fraction>map = new OpenIntToFieldHashMap(field);
        int key1 = 837989881;
        Fraction value1 = new Fraction(1);
        map.put(key1, value1);
        int key2 = 476463321;
        map.put(key2, value1);
        assertEquals(2, map.size());
        assertEquals(value1, map.get(key2));

        map.remove(key1);
        Fraction value2 = new Fraction(2);
        map.put(key2, value2);
        assertEquals(1, map.size());
        assertEquals(value2, map.get(key2));
    }


}