core/src/main/java/org/jclouds/reflect/Types2.java

/*
 * 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 "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jclouds.reflect;

import static com.google.common.base.Preconditions.checkState;

import java.lang.reflect.TypeVariable;

import com.google.common.annotations.Beta;
import com.google.common.reflect.TypeToken;

/**
 * @since 1.7
 */
@Beta
public class Types2 {

   /**
    * Helpful when you are capturing the type inside a constructor.
    * 
    * @throws IllegalStateException
    *            if the type is an instanceof {@link TypeVariable}
    */
   public static <T> TypeToken<T> checkBound(TypeToken<T> type) throws IllegalStateException {
      checkState(!(type.getType() instanceof TypeVariable<?>),
            "unbound type variable: %s, use ctor that explicitly assigns this", type);
      return type;
   }
}