alfresco-community-repo/source/java/org/alfresco/repo/cache/lookup/EntityLookupCacheTest.java

/*
 * Copyright (C) 2005-2009 Alfresco Software Limited.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 * As a special exception to the terms and conditions of version 2.0 of 
 * the GPL, you may redistribute this Program in connection with Free/Libre 
 * and Open Source Software ("FLOSS") applications as described in Alfresco's 
 * FLOSS exception.  You should have recieved a copy of the text describing 
 * the FLOSS exception, and it is also available here: 
 * http://www.alfresco.com/legal/licensing"
 */
package org.alfresco.repo.cache.lookup;

import java.util.Map;
import java.util.TreeMap;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import org.alfresco.repo.cache.MemoryCache;
import org.alfresco.repo.cache.SimpleCache;
import org.alfresco.repo.cache.lookup.EntityLookupCache.EntityLookup;
import org.alfresco.util.Pair;

/**
 * A cache for two-way lookups of database entities.  These are characterized by having a unique
 * key (perhaps a database ID) and a separate unique key that identifies the object.
 * <p>
 * The keys must have good <code>equals</code> and </code>hashCode</code> implementations and
 * must respect the case-sensitivity of the use-case.
 * 
 * @author Derek Hulley
 * @since 3.3
 */
public class EntityLookupCacheTest extends TestCase implements EntityLookup<Long, Object, String>
{
    private EntityLookupCache<Long, Object, String> entityLookupCache;
    private TreeMap<Long, String> database;

    @Override
    protected void setUp() throws Exception
    {
        SimpleCache<Long, Object> cache = new MemoryCache<Long, Object>();
        entityLookupCache = new EntityLookupCache<Long, Object, String>(cache, this);
        database = new TreeMap<Long, String>();
    }
    
    public void testLookupsUsingIncorrectValue() throws Exception
    {
        try
        {
            // Keep the "database" empty
            entityLookupCache.getByValue(this);
        }
        catch (AssertionFailedError e)
        {
            // Expected
        }
    }
    
    public void testLookupAgainstEmpty() throws Exception
    {
        TestValue value = new TestValue("AAA");
        Pair<Long, Object> entityPair = entityLookupCache.getByValue(value);
        assertNull(entityPair);
        assertTrue(database.isEmpty());
        
        // Now do lookup or create
        entityPair = entityLookupCache.getOrCreateByValue(value);
        assertNotNull("Expected a value to be found", entityPair);
        Long entityId = entityPair.getFirst();
        assertTrue("Database ID should have been created", database.containsKey(entityId));
        assertEquals("Database value incorrect", value.val, database.get(entityId));
        
        // Do lookup or create again
        entityPair = entityLookupCache.getOrCreateByValue(value);
        assertNotNull("Expected a value to be found", entityPair);
        assertEquals("Expected same entity ID", entityId, entityPair.getFirst());
        
        // Look it up using the value
        entityPair = entityLookupCache.getByValue(value);
        assertNotNull("Lookup after create should work", entityPair);
        
        // Look it up using the ID
        entityPair = entityLookupCache.getByKey(entityId);
        assertNotNull("Lookup by key should work after create", entityPair);
        assertTrue("Looked-up type incorrect", entityPair.getSecond() instanceof TestValue);
        assertEquals("Looked-up type value incorrect", value, entityPair.getSecond());
    }
    
    public void testLookupAgainstExisting() throws Exception
    {
        // Put some values in the "database"
        createValue(new TestValue("AAA"));
        createValue(new TestValue("BBB"));
        createValue(new TestValue("CCC"));
        
        // Look up by value
        Pair<Long, Object> entityPair = entityLookupCache.getByValue(new TestValue("AAA"));
        assertNotNull("Expected value to be found", entityPair);
        assertEquals("ID is incorrect", new Long(1), entityPair.getFirst());
        
        // Look up by ID
        entityPair = entityLookupCache.getByKey(new Long(2));
        assertNotNull("Expected value to be found", entityPair);
        
        // Do lookup or create
        entityPair = entityLookupCache.getByValue(new TestValue("CCC"));
        assertNotNull("Expected value to be found", entityPair);
        assertEquals("ID is incorrect", new Long(3), entityPair.getFirst());
    }

    /**
     * Helper class to represent business object
     */
    private static class TestValue
    {
        private final String val;
        private TestValue(String val)
        {
            this.val = val;
        }
        @Override
        public boolean equals(Object obj)
        {
            if (obj == null || !(obj instanceof TestValue))
            {
                return false;
            }
            return val.equals( ((TestValue)obj).val );
        }
        @Override
        public int hashCode()
        {
            return val.hashCode();
        }
        
    }
    
    @Override
    public String getValueKey(Object value)
    {
        assertNotNull(value);
        assertTrue(value instanceof TestValue);
        String dbValue = ((TestValue)value).val;
        return dbValue;
    }

    /**
     * Simulate creation of a new database entry
     */
    @Override
    public Pair<Long, Object> createValue(Object value)
    {
        assertNotNull(value);
        assertTrue(value instanceof TestValue);
        String dbValue = ((TestValue)value).val;
        
        // Get the last key
        Long lastKey = database.isEmpty() ? null : database.lastKey();
        Long newKey = null;
        if (lastKey == null)
        {
            newKey = new Long(1);
        }
        else
        {
            newKey = new Long(lastKey.longValue() + 1);
        }
        database.put(newKey, dbValue);
        return new Pair<Long, Object>(newKey, value);
    }

    @Override
    public Pair<Long, Object> findByKey(Long key)
    {
        assertNotNull(key);

        String dbValue = database.get(key);
        if (dbValue == null)
        {
            return null;
        }
        // Make a value object
        TestValue value = new TestValue(dbValue);
        return new Pair<Long, Object>(key, value);
    }

    @Override
    public Pair<Long, Object> findByValue(Object value)
    {
        assertNotNull(value);
        assertTrue(value instanceof TestValue);
        String dbValue = ((TestValue)value).val;

        for (Map.Entry<Long, String> entry : database.entrySet())
        {
            if (entry.getValue().equals(dbValue))
            {
                return new Pair<Long, Object>(entry.getKey(), entry.getValue());
            }
        }
        return null;
    }
}