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.ambari.client; import java.net.URI; import java.net.URL; import java.util.List; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.UriBuilder; import org.apache.ambari.common.rest.entities.StackInformation; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import com.sun.jersey.api.client.Client; import com.sun.jersey.api.client.ClientResponse; import com.sun.jersey.api.client.GenericType; import com.sun.jersey.api.client.WebResource; import com.sun.jersey.api.client.config.ClientConfig; import com.sun.jersey.api.client.config.DefaultClientConfig; public class StackHistory extends Command { String[] args = null; Options options = null; String urlPath = "/stacks"; URL resourceURL = null; CommandLine line; public StackHistory() { } public StackHistory(String[] args) throws Exception { /* * Build options for stack history */ this.args = args; addOptions(); this.resourceURL = new URL("" + this.baseURLString + this.urlPath); } public void printUsage() { HelpFormatter formatter = new HelpFormatter(); formatter.printHelp("ambari stack history", this.options); } public void addOptions() { Option help = new Option("help", "Help"); Option tree = new Option("tree", "tree representation"); OptionBuilder.withArgName("stack_name"); OptionBuilder.isRequired(); OptionBuilder.hasArg(); OptionBuilder.withDescription("Name of the stack"); Option name = OptionBuilder.create("name"); this.options = new Options(); options.addOption(name); options.addOption(tree); options.addOption(help); } public void parseCommandLine() { // create the parser CommandLineParser parser = new GnuParser(); try { // parse the command line arguments line = parser.parse(this.options, this.args); if (line.hasOption("help")) { printUsage(); System.exit(0); } } catch (ParseException exp) { // oops, something went wrong System.err.println("Command parsing failed. Reason: <" + exp.getMessage() + ">\n"); printUsage(); System.exit(-1); } } private static URI getBaseURI() { return UriBuilder.fromUri("http://localhost:4080/rest/").build(); } public void run() throws Exception { /* * Parse the command line to get the command line arguments */ parseCommandLine(); ClientConfig config = new DefaultClientConfig(); Client client = Client.create(config); WebResource service = client.resource(getBaseURI()); String stackName = line.getOptionValue("name"); boolean tree = line.hasOption("tree"); /* * Get stack revisions */ ClientResponse response = service.path("stacks/" + stackName + "/revisions") .accept(MediaType.APPLICATION_JSON).type(MediaType.APPLICATION_JSON).get(ClientResponse.class); if (response.getStatus() == 404) { System.out.println("Stack [" + stackName + "] does not exist"); System.exit(-1); } if (response.getStatus() == 204) { System.out.println("No revisions available for Stack [" + stackName + "]"); System.exit(0); } if (response.getStatus() != 200) { System.err.println("Stack history command failed. Reason [Code: <" + response.getStatus() + ">, Message: <" + response.getHeaders().getFirst("ErrorMessage") + ">]"); System.exit(-1); } /* * Retrieve the stack Information list from the response */ List<StackInformation> bpInfos = response.getEntity(new GenericType<List<StackInformation>>() { }); for (StackInformation bpInfo : bpInfos) { printStackInformation(service, bpInfo, tree); } } }