AbstractExtensionHolder.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.extension.holder;

import org.apache.log4j.Logger;
import org.wso2.siddhi.core.config.ExecutionPlanContext;
import org.wso2.siddhi.core.util.SiddhiConstants;

import java.util.HashMap;
import java.util.Map;

/**
 * Abstract Holder class to retrieve added extensions and store them in a map.
 */
public abstract class AbstractExtensionHolder {
    private static final Logger log = Logger.getLogger(AbstractExtensionHolder.class);

    protected Map<String, Class> extensionMap = new HashMap<String, Class>();

    protected AbstractExtensionHolder(Class clazz, ExecutionPlanContext executionPlanContext) {
        Map<String, Class> extensions = executionPlanContext.getSiddhiContext().getSiddhiExtensions();
        if (extensions != null) {
            for (String extensionKey : executionPlanContext.getSiddhiContext().getSiddhiExtensions().keySet()) {
                Class extension = extensions.get(extensionKey);
                if (clazz.isAssignableFrom(extension)) {
                    if (extensionMap.containsKey(extensionKey)) {
                        log.error("Extension class " + extension.getName() + " not loaded, as there is already an" +
                                          " matching extension '" + extensionKey + "' implemented as " + extensionMap
                                .get
                                        (extensionKey).getName());
                    } else {
                        extensionMap.put(extensionKey, extension);
                    }

                }

            }
        }
    }

    public Class getExtension(String namespace, String function) {
        if (!namespace.isEmpty()) {
            return extensionMap.get(namespace + SiddhiConstants.EXTENSION_SEPARATOR + function);
        } else {
            return extensionMap.get(function);
        }
    }

}