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Dependency injection library with reference count

There is a newer version: 2.2.0

/*
 * Copyright 2015 Kejun Xia
 *
 * Licensed 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 com.shipdream.lib.poke;

import com.shipdream.lib.poke.exception.ProvideException;
import com.shipdream.lib.poke.util.ReflectUtils;

/**
 * This provider uses default/empty constructor by provided class name to get dependencies. So
 * make sure the implementation has default public constructor
 */
public class ProviderByClassName extends Provider {
    private final Class clazz;

    protected ProviderByClassName(Class type, Class implementationClass) {
        super(type, ReflectUtils.findFirstQualifier(implementationClass));
        this.clazz = implementationClass;
    }

    /**
     * Construct a {@link ProviderByClassName} with {@link javax.inject.Qualifier}
     *
     * @param type
     * @param implementationClassName
     * @throws ClassNotFoundException
     */
    public ProviderByClassName(Class type, String implementationClassName) throws ClassNotFoundException {
        super(type, ReflectUtils.findFirstQualifier(Class.forName(implementationClassName)));
        this.clazz = (Class) Class.forName(implementationClassName);
    }

    @Override
    public Object createInstance() throws ProvideException {
        try {
            return clazz.newInstance();
        } catch (InstantiationException e) {
            throwProvideException(e);
        } catch (IllegalAccessException e) {
            throwProvideException(e);
        }

        throw new ProvideException(String.format("Failed to provide class - %s as newInstance " +
                "of it returns null"));
    }

    private void throwProvideException(Exception e) throws ProvideException {
        throw new ProvideException(String.format("Failed to provide class - %s", clazz.getName()), e);
    }

}