SiddhiClassLoader.java

/*
 * Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. 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.wso2.siddhi.core.util;

import org.wso2.siddhi.core.exception.CannotLoadClassException;
import org.wso2.siddhi.core.exception.ExecutionPlanCreationException;
import org.wso2.siddhi.core.util.extension.holder.AbstractExtensionHolder;
import org.wso2.siddhi.query.api.extension.Extension;

/**
 * used to load classes required for Siddhi extensions.
 */
public class SiddhiClassLoader {

    private static Object loadClass(Class clazz) throws CannotLoadClassException {
        try {
            return clazz.newInstance();
        } catch (InstantiationException e) {
            throw new CannotLoadClassException("Cannot restore class: " + clazz.getName(), e);
        } catch (IllegalAccessException e) {
            throw new CannotLoadClassException("Cannot restore class: " + clazz.getName(), e);
        }
    }

    public static Object loadExtensionImplementation(Extension extension,
                                                     AbstractExtensionHolder extensionHolder) {
        Class clazz = extensionHolder.getExtension(extension.getNamespace(), extension.getName());
        if (clazz == null) {
            throw new ExecutionPlanCreationException("No extension exist for " + extension.getNamespace() + ":" +
                                                             extension.getName(), true);
        }
        try {
            return SiddhiClassLoader.loadClass(clazz);
        } catch (CannotLoadClassException e) {
            throw new ExecutionPlanCreationException("Extension " + clazz.getName() + " cannot be loaded!", true);

        }
    }


}