/**************************************************************************************
 * Copyright (C) 2008 EsperTech, Inc. All rights reserved.                            *
 * http://esper.codehaus.org                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esper.util;

import com.espertech.esper.collection.Pair;

import java.util.concurrent.CopyOnWriteArraySet;
import java.util.Set;
import java.util.HashSet;

/**
 * Cast implementation for non-numeric values that caches allowed casts assuming there is a small set of casts allowed. 
 */
public class SimpleTypeCasterAnyType implements SimpleTypeCaster
{
    private Class typeToCastTo;
    private CopyOnWriteArraySet<Pair<Class, Boolean>> pairs = new CopyOnWriteArraySet<Pair<Class, Boolean>>();

    /**
     * Ctor.
     * @param typeToCastTo is the target type
     */
    public SimpleTypeCasterAnyType(Class typeToCastTo)
    {
        this.typeToCastTo = typeToCastTo;
    }

    public boolean isNumericCast()
    {
        return false;
    }

    public Object cast(Object object)
    {
        if (object.getClass() == typeToCastTo)
        {
            return object;
        }

        // check cache to see if this is cast-able
        for (Pair<Class, Boolean> pair : pairs)
        {
            if (pair.getFirst() == typeToCastTo)
            {
                if (!pair.getSecond())
                {
                    return null;
                }
                return object;
            }
        }

        // Not found in cache, add to cache;
        synchronized(this)
        {
            // search cache once more
            for (Pair<Class, Boolean> pair : pairs)
            {
                if (pair.getFirst() == typeToCastTo)
                {
                    if (!pair.getSecond())
                    {
                        return null;
                    }
                    return object;
                }
            }

            // Determine if any of the super-types and interfaces that the object implements or extends
            // is the same as any of the target types
            Set<Class> classesToCheck = new HashSet<Class>();
            JavaClassHelper.getSuper(object.getClass(), classesToCheck);

            if (classesToCheck.contains(typeToCastTo))
            {
                pairs.add(new Pair<Class, Boolean>(object.getClass(), true));
                return object;
            }
            pairs.add(new Pair<Class, Boolean>(object.getClass(), false));
            return null;
        }
    }
}