Java Reflection Type getRawType(Type type)

Description

Copied from com.google.inject.internal.MoreTypes.getRawType(Type)

License

Open Source License

Declaration

public static Class<?> getRawType(Type type) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright (c) 2010 itemis AG (http://www.itemis.eu) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/

import java.lang.reflect.Array;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.text.MessageFormat;

public class Main {
    /**/*from   ww w.  j ava 2s .co  m*/
     * Copied from com.google.inject.internal.MoreTypes.getRawType(Type)
     * @since 2.8
     */
    public static Class<?> getRawType(Type type) {
        if (type instanceof Class<?>) {
            // type is a normal class.
            return (Class<?>) type;

        } else if (type instanceof ParameterizedType) {
            ParameterizedType parameterizedType = (ParameterizedType) type;

            // I'm not exactly sure why getRawType() returns Type instead of Class.
            // Neal isn't either but suspects some pathological case related
            // to nested classes exists.
            Type rawType = parameterizedType.getRawType();
            if (!(rawType instanceof Class)) {
                String message = MessageFormat.format("Expected a Class, but <{0}> is of type {1}", type,
                        type.getClass().getName());
                throw new IllegalArgumentException(message);
            }
            return (Class<?>) rawType;

        } else if (type instanceof GenericArrayType) {
            Type componentType = ((GenericArrayType) type).getGenericComponentType();
            return Array.newInstance(getRawType(componentType), 0).getClass();

        } else if (type instanceof TypeVariable) {
            // we could use the variable's bounds, but that'll won't work if there are multiple.
            // having a raw type that's more general than necessary is okay  
            return Object.class;

        } else {
            throw new IllegalArgumentException("Expected a Class, ParameterizedType, or "
                    + "GenericArrayType, but <" + type + "> is of type " + type.getClass().getName());
        }
    }
}