EntityType.java

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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
 * 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
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 *  KIND, either express or implied.  See the License for the
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package org.apache.wink.client;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import org.apache.wink.common.internal.i18n.Messages;
import org.apache.wink.common.internal.utils.GenericsUtils;

/**
 * The EntityType is used to specify the class type and the generic type of
 * responses.
 * <p>
 * Typically, an anonymous EntityType instance is created in order to specify
 * the response type, like so:
 * 
 * <pre>
 * Resource resource = client.resource(uri);
 * List<String> list = resource.get(new EntityType<List<String>>() {
 * });
 * </pre>
 * 
 * @param <T>
 *            the entity type
 */
public class EntityType<T> {

	private Type type;

	private Class<T> cls;

	/**
	 * Construct a new entity type. The constructor is protected to force
	 * extension of this class, in order to enable the extraction of the generic
	 * type and the class type from the superclass.
	 * 
	 * @throws ClientRuntimeException
	 *             if there are exceptions generating the type information, most
	 *             notably if the derived type is not parameterized
	 */
	@SuppressWarnings("unchecked")
	protected EntityType() {
		Type superclass = this.getClass().getGenericSuperclass();
		if (!(superclass instanceof ParameterizedType)) {
			throw new ClientRuntimeException(Messages
					.getMessage("entityTypeMustBeParameterized")); //$NON-NLS-1$
		}
		this.type = ((ParameterizedType) superclass).getActualTypeArguments()[0];
		this.cls = (Class<T>) GenericsUtils.getClassType(type, this.getClass());
	}

	public Type getType() {
		return type;
	}

	public Class<T> getRawClass() {
		return cls;
	}

}