Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF 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.apache.hadoop.yarn.webapp; import static com.google.common.base.Preconditions.checkNotNull; import java.net.InetSocketAddress; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.commons.lang3.StringUtils; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.http.HttpServer2; import org.apache.hadoop.yarn.webapp.view.RobotsTextPage; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.base.Splitter; import com.google.common.collect.Lists; import com.google.inject.Provides; import com.google.inject.servlet.GuiceFilter; import com.google.inject.servlet.ServletModule; import com.sun.jersey.api.container.filter.GZIPContentEncodingFilter; import com.sun.jersey.api.core.ResourceConfig; import com.sun.jersey.core.util.FeaturesAndProperties; import com.sun.jersey.guice.spi.container.servlet.GuiceContainer; import com.sun.jersey.spi.container.servlet.ServletContainer; /** * @see WebApps for a usage example */ @InterfaceAudience.LimitedPrivate({ "YARN", "MapReduce" }) public abstract class WebApp extends ServletModule { private static final Logger LOG = LoggerFactory.getLogger(WebApp.class); public enum HTTP { GET, POST, HEAD, PUT, DELETE }; private volatile String name; private volatile List<String> servePathSpecs = new ArrayList<String>(); // path to redirect to private volatile String redirectPath; private volatile String wsName; private volatile Configuration conf; private volatile HttpServer2 httpServer; private volatile GuiceFilter guiceFilter; private final Router router = new Router(); // index for the parsed route result static final int R_PATH = 0; static final int R_CONTROLLER = 1; static final int R_ACTION = 2; static final int R_PARAMS = 3; static final Splitter pathSplitter = Splitter.on('/').trimResults().omitEmptyStrings(); void setHttpServer(HttpServer2 server) { httpServer = checkNotNull(server, "http server"); } @Provides public HttpServer2 httpServer() { return httpServer; } /** * Get the address the http server is bound to * @return InetSocketAddress */ public InetSocketAddress getListenerAddress() { return checkNotNull(httpServer, "httpServer").getConnectorAddress(0); } public int port() { InetSocketAddress addr = checkNotNull(httpServer, "httpServer").getConnectorAddress(0); return addr == null ? -1 : addr.getPort(); } public void stop() { try { checkNotNull(httpServer, "httpServer").stop(); checkNotNull(guiceFilter, "guiceFilter").destroy(); } catch (Exception e) { throw new WebAppException(e); } } public void joinThread() { try { checkNotNull(httpServer, "httpServer").join(); } catch (InterruptedException e) { LOG.info("interrupted", e); } } void setConf(Configuration conf) { this.conf = conf; } @Provides public Configuration conf() { return conf; } @Provides Router router() { return router; } @Provides WebApp webApp() { return this; } void setName(String name) { this.name = name; } public String name() { return this.name; } public String wsName() { return this.wsName; } void addServePathSpec(String path) { this.servePathSpecs.add(path); } public String[] getServePathSpecs() { return this.servePathSpecs.toArray(new String[this.servePathSpecs.size()]); } /** * Set a path to redirect the user to if they just go to "/". For * instance "/" goes to "/yarn/apps". This allows the filters to * more easily differentiate the different webapps. * @param path the path to redirect to */ void setRedirectPath(String path) { this.redirectPath = path; } void setWebServices(String name) { this.wsName = name; } public String getRedirectPath() { return this.redirectPath; } void setHostClass(Class<?> cls) { router.setHostClass(cls); } void setGuiceFilter(GuiceFilter instance) { guiceFilter = instance; } @Override public void configureServlets() { setup(); serve("/", "/__stop", RobotsTextPage.ROBOTS_TXT_PATH).with(Dispatcher.class); for (String path : this.servePathSpecs) { serve(path).with(Dispatcher.class); } configureWebAppServlets(); } protected void configureWebAppServlets() { // Add in the web services filters/serves if app has them. // Using Jersey/guice integration module. If user has web services // they must have also bound a default one in their webapp code. if (this.wsName != null) { // There seems to be an issue with the guice/jersey integration // where we have to list the stuff we don't want it to serve // through the guicecontainer. In this case its everything except // the the web services api prefix. We can't just change the filter // from /* below - that doesn't work. String regex = "(?!/" + this.wsName + ")"; serveRegex(regex).with(DefaultWrapperServlet.class); Map<String, String> params = new HashMap<String, String>(); params.put(ResourceConfig.FEATURE_IMPLICIT_VIEWABLES, "true"); params.put(ServletContainer.FEATURE_FILTER_FORWARD_ON_404, "true"); params.put(FeaturesAndProperties.FEATURE_XMLROOTELEMENT_PROCESSING, "true"); params.put(ResourceConfig.PROPERTY_CONTAINER_REQUEST_FILTERS, GZIPContentEncodingFilter.class.getName()); params.put(ResourceConfig.PROPERTY_CONTAINER_RESPONSE_FILTERS, GZIPContentEncodingFilter.class.getName()); filter("/*").through(getWebAppFilterClass(), params); } } protected Class<? extends GuiceContainer> getWebAppFilterClass() { return GuiceContainer.class; } /** * Setup of a webapp serving route. * @param method the http method for the route * @param pathSpec the path spec in the form of /controller/action/:args etc. * @param cls the controller class * @param action the controller method */ public void route(HTTP method, String pathSpec, Class<? extends Controller> cls, String action) { List<String> res = parseRoute(pathSpec); router.add(method, res.get(R_PATH), cls, action, res.subList(R_PARAMS, res.size())); } /** * Setup of a webapp serving route without default views added to the page. * @param pathSpec the path spec in the form of /controller/action/:args etc. * @param cls the controller class * @param action the controller method */ public void routeWithoutDefaultView(String pathSpec, Class<? extends Controller> cls, String action) { List<String> res = parseRoute(pathSpec); router.addWithoutDefaultView(HTTP.GET, res.get(R_PATH), cls, action, res.subList(R_PARAMS, res.size())); } public void route(String pathSpec, Class<? extends Controller> cls, String action) { route(HTTP.GET, pathSpec, cls, action); } public void route(String pathSpec, Class<? extends Controller> cls) { List<String> res = parseRoute(pathSpec); router.add(HTTP.GET, res.get(R_PATH), cls, res.get(R_ACTION), res.subList(R_PARAMS, res.size())); } /** * /controller/action/:args => [/controller/action, controller, action, args] * /controller/:args => [/controller, controller, index, args] */ static List<String> parseRoute(String pathSpec) { List<String> result = Lists.newArrayList(); result.add(getPrefix(checkNotNull(pathSpec, "pathSpec"))); Iterable<String> parts = pathSplitter.split(pathSpec); String controller = null, action = null; for (String s : parts) { if (controller == null) { if (s.charAt(0) == ':') { controller = "default"; result.add(controller); action = "index"; result.add(action); } else { controller = s; } } else if (action == null) { if (s.charAt(0) == ':') { action = "index"; result.add(action); } else { action = s; } } result.add(s); } if (controller == null) { result.add("default"); } if (action == null) { result.add("index"); } return result; } static String getPrefix(String pathSpec) { int start = 0; while (StringUtils.isAnyBlank(Character.toString(pathSpec.charAt(start)))) { ++start; } if (pathSpec.charAt(start) != '/') { throw new WebAppException("Path spec syntax error: " + pathSpec); } int ci = pathSpec.indexOf(':'); if (ci == -1) { ci = pathSpec.length(); } if (ci == 1) { return "/"; } char c; do { c = pathSpec.charAt(--ci); } while (c == '/' || StringUtils.isAnyBlank(Character.toString(c))); return pathSpec.substring(start, ci + 1); } public abstract void setup(); }