Java tutorial
/* * Copyright 2013-2016 Amazon Technologies, Inc. * * 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://aws.amazon.com/apache2.0 * * This file 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 core.com.qiniu.regions; import static core.com.qiniu.SDKGlobalConfiguration.REGIONS_FILE_OVERRIDE_SYSTEM_PROPERTY; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import java.net.MalformedURLException; import java.net.URI; import java.net.URISyntaxException; import java.util.LinkedList; import java.util.List; /** * Utilities for working with regions. */ public class RegionUtils { private static List<Region> regions; // Use the same logger as the http client private static final Log log = LogFactory.getLog("com.qiniu.request"); /** * Returns a list of the available AWS regions. */ public synchronized static List<Region> getRegions() { if (regions == null) { init(); } return regions; } /** * Returns a list of the regions that support the service given. * * @see ServiceAbbreviations */ public synchronized static List<Region> getRegionsForService(String serviceAbbreviation) { List<Region> regions = new LinkedList<Region>(); for (Region r : getRegions()) { if (r.isServiceSupported(serviceAbbreviation)) { regions.add(r); } } return regions; } /** * Returns the region with the id given, if it exists. Otherwise, returns * null. */ public static Region getRegion(String regionName) { for (Region r : getRegions()) { if (r.getName().equals(regionName)) { return r; } } return null; } /** * Searches through all known regions to find one with any service at the * specified endpoint. If no region is found with a service at that * endpoint, an exception is thrown. * * @param endpoint The endpoint for any service residing in the desired * region. * @return The region containing any service running at the specified * endpoint, otherwise an exception is thrown if no region is found * with a service at the specified endpoint. * @throws MalformedURLException If the given URL is malformed, or if the * one of the service URLs on record is malformed. */ public static Region getRegionByEndpoint(String endpoint) { URI targetEndpointUri = getUriByEndpoint(endpoint); String targetHost = targetEndpointUri.getHost(); for (Region region : getRegions()) { for (String serviceEndpoint : region.getServiceEndpoints().values()) { URI serviceEndpointUrl = getUriByEndpoint(serviceEndpoint); if (serviceEndpointUrl.getHost().equals(targetHost)) return region; } } throw new IllegalArgumentException("No region found with any service for endpoint " + endpoint); } /** * There is no need to call this method, it is public only for * Compatibility. Every regions method makes sure this method has already * been called. This method will load the regions (specified by the * developer if the system property * SDKGlobalConfiguraiton.REGIONS_FILE_OVERRIDE_SYSTEM_PROPERTY is set, or * the defaults shipped with the SDK) into memory. */ public static synchronized void init() { if (System.getProperty(REGIONS_FILE_OVERRIDE_SYSTEM_PROPERTY) != null) { try { loadRegionsFromOverrideFile(); } catch (FileNotFoundException e) { throw new RuntimeException("Couldn't find regions override file specified", e); } } // Fall back onto the version we ship with the SDK if (regions == null) { initSDKRegions(); } // Throw out RuntimeException explicitly if (regions == null) { throw new RuntimeException("Failed to initialize the regions."); } } private static void loadRegionsFromOverrideFile() throws FileNotFoundException { String overrideFilePath = System.getProperty(REGIONS_FILE_OVERRIDE_SYSTEM_PROPERTY); if (log.isDebugEnabled()) { log.debug("Using local override of the regions file (" + overrideFilePath + ") to initiate regions data..."); } File regionsFile = new File(overrideFilePath); FileInputStream override = new FileInputStream(regionsFile); initRegions(override); } /** * Tries to initialize the regions list from the stream given. * * @param regionsFile The input stream pointing to the retrieved region * file. */ private static void initRegions(InputStream regionsFile) { try { RegionMetadataParser parser = new RegionMetadataParser(); regions = parser.parseRegionMetadata(regionsFile); } catch (Exception e) { log.warn("Failed to parse regional endpoints", e); } } /** * Failsafe method to initialize the regions list from the list bundled with * the SDK, in case it cannot be fetched from the remote source. */ private static void initSDKRegions() { if (log.isDebugEnabled()) { log.debug("Initializing the regions with default regions"); } regions = RegionDefaults.getRegions(); } /** * Get the URI object for the given endpoint. URI class cannot correctly * parse the endpoint if it doesn't include protocol. This method will add * the protocol if this happens. */ private static URI getUriByEndpoint(String endpoint) { URI targetEndpointUri = null; try { targetEndpointUri = new URI(endpoint); if (targetEndpointUri.getHost() == null) { targetEndpointUri = new URI("http://" + endpoint); } } catch (URISyntaxException e) { throw new RuntimeException("Unable to parse service endpoint: " + e.getMessage()); } return targetEndpointUri; } }