TestArrayMap.java

/**
 * Copyright (c) 2002-2011 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.kernel.impl.util;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;

import java.lang.reflect.Field;
import java.util.Map;

import org.junit.Test;

public class TestArrayMap
{
    @Test
	public void testArrayMap()
	{
		ArrayMap<String,Integer> map = new ArrayMap<String,Integer>();

		assertTrue( map.get( "key1" ) == null );
		map.put( "key1", 0 );
		assertEquals( new Integer(0), map.get( "key1" ) );
		assertEquals( new Integer(0), map.get( "key1" ) );
		map.put( "key1", 1 );
		assertEquals( new Integer(1), map.get( "key1" ) );
		map.put( "key2", 0 );
		assertEquals( new Integer(0), map.get( "key2" ) );
		map.put( "key2", 2 );
		assertEquals( new Integer(2), map.get( "key2" ) );
		assertEquals( new Integer(2), map.remove( "key2" ) );
		assertTrue( map.get( "key2" ) == null );
		assertEquals( new Integer(1), map.get( "key1" ) );
		assertEquals( new Integer(1), map.remove( "key1" ) );
		assertTrue( map.get( "key1" ) == null );

		map.put( "key1", 1 );
		map.put( "key2", 2 );
		map.put( "key3", 3 );
		map.put( "key4", 4 );
		map.put( "key5", 5 );
		assertEquals( new Integer(5), map.get( "key5" ) );
		assertEquals( new Integer(4), map.get( "key4" ) );
		assertEquals( new Integer(3), map.get( "key3" ) );
		assertEquals( new Integer(2), map.get( "key2" ) );
		assertEquals( new Integer(1), map.get( "key1" ) );
		assertEquals( new Integer(5), map.remove( "key5" ) );
		assertEquals( new Integer(1), map.get( "key1" ) );
		assertEquals( new Integer(4), map.get( "key4" ) );
		assertEquals( new Integer(3), map.get( "key3" ) );
		assertEquals( new Integer(2), map.get( "key2" ) );
		assertEquals( new Integer(3), map.remove( "key3" ) );
		assertEquals( new Integer(1), map.remove( "key1" ) );
		assertEquals( new Integer(2), map.remove( "key2" ) );

		for ( int i = 0; i < 100; i++ )
		{
			map.put( "key" + i, i );
		}
		for ( int i = 0; i < 100; i++ )
		{
			assertEquals( new Integer(i), map.get( "key" + i) );
		}
		for ( int i = 0; i < 100; i++ )
		{
			assertEquals( new Integer(i), map.remove( "key" + i) );
		}
		for ( int i = 0; i < 100; i++ )
		{
			assertTrue( map.get( "key" + i ) == null );
		}
    }

    @Test
    public void arraymapIsClearedWhenExpandingToHashMapIfNonShrinkable() throws Exception
    {
        assertArrayMapIsClearedWhenExpandingToHashMap( new ArrayMap<String, Integer>( 3, false,
                false ), false );
    }

    @Test
    public void arraymapIsClearedWhenExpandingToHashMapIfShrinkable() throws Exception
    {
        assertArrayMapIsClearedWhenExpandingToHashMap( new ArrayMap<String, Integer>( 3, false,
                true ), true );
    }

    @Test
    public void arraymapIsClearedWhenExpandingToHashMapIfNonShrinkableAndSynchronized()
            throws Exception
    {
        assertArrayMapIsClearedWhenExpandingToHashMap( new ArrayMap<String, Integer>( 3, true,
                false ), false );
    }

    @Test
    public void arraymapIsClearedWhenExpandingToHashMapIfShrinkableAndSynchronized()
            throws Exception
    {
        assertArrayMapIsClearedWhenExpandingToHashMap(
                new ArrayMap<String, Integer>( 3, true, true ), true );
    }

    private void assertArrayMapIsClearedWhenExpandingToHashMap( ArrayMap<String, Integer> map,
            boolean shrinkable )
            throws Exception
    {
        // Perhaps not the pretties solution... quite brittle...
        Field expansion = ArrayMap.class.getDeclaredField( "propertyMap" );
        Field array = ArrayMap.class.getDeclaredField( "arrayEntries" );
        expansion.setAccessible( true );
        array.setAccessible( true );

        map.put( "key1", 1 );
        map.put( "key2", 2 );
        map.put( "key3", 3 );
        map.put( "key4", 4 );
        map.put( "key5", 5 );

        Object[] data = (Object[]) array.get( map );
        if ( data != null ) for ( int i = 0; i < data.length; i++ )
        {
            assertNull( "Nonnull element", data[i] );
        }

        map.remove( "key1" );
        map.remove( "key2" );
        map.remove( "key3" );

        if ( shrinkable )
        {
            Map<?, ?> exp = (Map<?, ?>) expansion.get( map );
            assertTrue( "Data still expanded", exp == null || exp.size() == 0 );
        }
    }

    @Test
    public void canOverwriteThenRemoveElementAcrossDeflation() throws Exception
    {
        ArrayMap<String, Integer> map = new ArrayMap<String, Integer>( 3, false, true );

        map.put( "key1", 1 );
        map.put( "key2", 2 );
        map.put( "key3", 3 );
        map.put( "key4", 4 );
        map.put( "key5", 5 );

        map.put( "key1", 6 );

        map.remove( "key1" );
        assertNull( "removed element still found", map.get( "key1" ) );
        map.remove( "key2" );
        assertNull( "removed element still found", map.get( "key1" ) );
        map.remove( "key3" );
        assertNull( "removed element still found", map.get( "key1" ) );
        map.remove( "key4" );
        assertNull( "removed element still found", map.get( "key1" ) );
    }
}