pf4j/pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionWrapper.java

/*
 * Copyright 2014 Decebal Suiu
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
 * the License. You may obtain a copy of the License in the LICENSE file, or 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 ro.fortsoft.pf4j;

/**
 * A wrapper over extension instance.
 *
 * @author Decebal Suiu
 */
public class ExtensionWrapper<T> implements Comparable<ExtensionWrapper<T>> {

    ExtensionDescriptor descriptor;
    ExtensionFactory extensionFactory;
    T extension; // cache

	public ExtensionWrapper(ExtensionDescriptor descriptor) {
        this.descriptor = descriptor;
	}

	public T getExtension() {
        if (extension == null) {
            extension = (T) extensionFactory.create(descriptor.getExtensionClass());
        }

        return extension;
	}

    public ExtensionDescriptor getDescriptor() {
        return descriptor;
    }

    public int getOrdinal() {
		return descriptor.getOrdinal();
	}

	@Override
	public int compareTo(ExtensionWrapper<T> o) {
		return (getOrdinal() - o.getOrdinal());
	}

    void setExtensionFactory(ExtensionFactory extensionFactory) {
        this.extensionFactory = extensionFactory;
    }

}