org.wso2.carbon.analytics.dashboard.admin.RegistryUtils.java Source code

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Here is the source code for org.wso2.carbon.analytics.dashboard.admin.RegistryUtils.java

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/**
 * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
    
 * 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 org.wso2.carbon.analytics.dashboard.admin;

import com.google.gson.Gson;
import org.apache.axis2.AxisFault;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.wso2.carbon.context.CarbonContext;
import org.wso2.carbon.context.RegistryType;
import org.wso2.carbon.registry.api.Collection;
import org.wso2.carbon.registry.api.Registry;
import org.wso2.carbon.registry.api.RegistryException;
import org.wso2.carbon.registry.api.Resource;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class RegistryUtils {

    //TODO- Use privileged carbon context
    private static CarbonContext carbonContext = CarbonContext.getThreadLocalCarbonContext();
    private static Registry registry = carbonContext.getRegistry(RegistryType.SYSTEM_GOVERNANCE);

    /**
     * Logger
     */
    private static Log logger = LogFactory.getLog(RegistryUtils.class);
    public static final String APPLICATION_JSON = "application/json";

    /**
     * Creates a collection in the given location.
     * @param url URL of the collection to be created.
     */
    public static void createCollection(String url) throws RegistryException {
        Collection collection = registry.newCollection();
        registry.put(url, collection);
    }

    /**
     * Writes an object to the given registry url and registry type as a Json String.
     *
     * @param url     Relative url to where the resource will be saved.
     * @param content Data to be written to the registry as a json string. Must be a bean object(eg- String objects are not supported).
     */
    public static void writeResource(String url, Object content) throws RegistryException {
        Gson gson = new Gson();
        Resource resource = registry.newResource(); //new resource in the registry
        resource.setContent(gson.toJson(content));
        resource.setMediaType(APPLICATION_JSON);
        registry.put(url, resource);
    }

    /**
     * Reads a resource from the registry
     *
     * @param url         Relative url from where the resource will be read.
     * @param targetClass Target object type which the json content will be mapped into.
     * @return Object by mapping into a given class, the json read from the registry.
     */
    public static Object readResource(String url, Class targetClass) throws RegistryException {
        InputStream contentStream = null;
        InputStreamReader isr = null;
        Gson gson = new Gson();
        try {
            Resource resource = registry.get(url);
            contentStream = resource.getContentStream();
            isr = new InputStreamReader(contentStream);
            return gson.fromJson(isr, targetClass);
        } catch (RegistryException e) {
            logger.error("An error occurred while reading resource [" + url + "] from registry", e);
            throw e;
        } finally {
            closeQuitely(contentStream);
            closeQuitely(isr);
        }
    }

    /**
     * Close colseables
     */
    private static void closeQuitely(Closeable closeable) {
        try {
            if (closeable != null) {
                closeable.close();
            }
        } catch (IOException ignore) {
            /* ignore */
        }
    }

    /**
     * Checks if a resource with given name(url->location+resource name) exits in the registry.
     *
     * @param url Resource url relative to the registry.
     * @return True if resource exists.
     * @throws AxisFault .
     */
    public static boolean isResourceExist(String url) throws RegistryException {
        return registry.resourceExists(url);
    }

    /**
     * Get all the resources in a directory url as a Collection.
     *
     * @param collectionURL Collection url relative to the registry.
     * @return Collection.
     * @throws AxisFault
     */
    public static Collection readCollection(String collectionURL) throws AxisFault {

        try {
            return (Collection) registry.get(collectionURL);
        } catch (Exception e) {
            String errorMessage = "Unable to read resource collection from url:" + collectionURL;
            logger.error(errorMessage);
            throw new AxisFault(errorMessage);
        }
    }

    /**
     * @param url url of the resource to be deleted from the registry.
     * @throws AxisFault
     */
    public static boolean deleteResource(String url) throws AxisFault {
        try {
            registry.delete(url);
            return true;
        } catch (Exception e) {
            String errorMessage = "Unable to delete resource at url:" + url;
            logger.error(errorMessage);
            return false;
        }
    }

}