org.apache.mahout.common.ClassUtils.java Source code

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Here is the source code for org.apache.mahout.common.ClassUtils.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 "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.apache.mahout.common;

import java.lang.reflect.InvocationTargetException;

public final class ClassUtils {

    private ClassUtils() {
    }

    public static <T> T instantiateAs(String classname, Class<T> asSubclassOfClass) {
        try {
            return instantiateAs(Class.forName(classname).asSubclass(asSubclassOfClass), asSubclassOfClass);
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException(e);
        }
    }

    public static <T> T instantiateAs(String classname, Class<T> asSubclassOfClass, Class<?>[] params,
            Object[] args) {
        try {
            return instantiateAs(Class.forName(classname).asSubclass(asSubclassOfClass), asSubclassOfClass, params,
                    args);
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException(e);
        }
    }

    public static <T> T instantiateAs(Class<? extends T> clazz, Class<T> asSubclassOfClass, Class<?>[] params,
            Object[] args) {
        try {
            return clazz.asSubclass(asSubclassOfClass).getConstructor(params).newInstance(args);
        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException
                | InvocationTargetException ie) {
            throw new IllegalStateException(ie);
        }
    }

    public static <T> T instantiateAs(Class<? extends T> clazz, Class<T> asSubclassOfClass) {
        try {
            return clazz.asSubclass(asSubclassOfClass).getConstructor().newInstance();
        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException
                | InvocationTargetException ie) {
            throw new IllegalStateException(ie);
        }
    }
}