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 *   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
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 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
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package org.apache.cayenne.lifecycle.id;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.cayenne.ObjectId;
import org.apache.cayenne.Persistent;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.ObjEntity;

/**
 * An object to encode/decode ObjectIds for all entities found in a mapping namespace.
 * 
 * @since 3.1
 */
public class IdCoder {

    protected EntityResolver entityResolver;
    protected Map coders;

    public IdCoder(EntityResolver entityResolver) {
        this.entityResolver = entityResolver;
        this.coders = new ConcurrentHashMap();
    }

    /**
     * Returns an ObjectId for a given String ID.
     */
    public ObjectId getObjectId(String id) {

        String entityName = EntityIdCoder.getEntityName(id);
        EntityIdCoder coder = getCoder(entityName);
        return coder.toObjectId(id);
    }

    public String getStringId(Persistent referenceable) {

        if (referenceable == null) {
            throw new NullPointerException("Null object");
        }

        ObjectId id = referenceable.getObjectId();

        EntityIdCoder coder = getCoder(id.getEntityName());
        return coder.toStringId(id);
    }

    protected EntityIdCoder getCoder(String entityName) {
        EntityIdCoder coder = coders.get(entityName);
        if (coder == null) {

            coder = createCoder(entityName);
            coders.put(entityName, coder);
        }

        return coder;
    }

    protected EntityIdCoder createCoder(String entityName) {
        ObjEntity entity = entityResolver.getObjEntity(entityName);
        if (entity == null) {
            throw new IllegalArgumentException("Entity '"
                    + entityName
                    + "' is not mapped");
        }

        return new EntityIdCoder(entity);
    }
}