com.cloudera.csd.tools.codahale.AbstractCodahaleFixtureGenerator.java Source code

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Here is the source code for com.cloudera.csd.tools.codahale.AbstractCodahaleFixtureGenerator.java

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// Licensed to Cloudera, Inc. under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  Cloudera, 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 com.cloudera.csd.tools.codahale;

import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

import java.io.BufferedWriter;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.DefaultParser;
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 org.apache.commons.configuration.MapConfiguration;
import org.apache.commons.io.IOUtils;

/**
 * A generic codahale monitoring fixture generator application to take care of
 * the rote options handling.
 */
public abstract class AbstractCodahaleFixtureGenerator {

    protected static final String CODAHALE_OUT_DEFAULT_FILE_NAME = "codahale_monitoring_defintions.json";

    @SuppressWarnings({ "AccessStaticViaInstance", "static-access" })
    protected static final Option OPT_GENERATED_OUPTUT = OptionBuilder.withLongOpt("out").withArgName("FILE")
            .hasArg().withDescription("The generated codahale metric definition file name. By "
                    + "default codahale_monitoring_defintions.json will be used.")
            .isRequired(false).create("o");

    protected static final Options DEFAULT_OPTIONS;

    static {
        DEFAULT_OPTIONS = new Options();
        DEFAULT_OPTIONS.addOption(OPT_GENERATED_OUPTUT);
    }

    protected final MapConfiguration config;

    public AbstractCodahaleFixtureGenerator(String[] args) throws Exception {
        this(args, DEFAULT_OPTIONS);
    }

    public AbstractCodahaleFixtureGenerator(String[] args, Options options) throws Exception {
        Preconditions.checkNotNull(args);
        Preconditions.checkNotNull(options);

        CommandLineParser parser = new DefaultParser();
        try {
            CommandLine cmdLine = parser.parse(options, args);
            if (!cmdLine.getArgList().isEmpty()) {
                throw new ParseException("Unexpected extra arguments: " + cmdLine.getArgList());
            }
            config = new MapConfiguration(Maps.<String, Object>newHashMap());
            for (Option option : cmdLine.getOptions()) {
                config.addProperty(option.getLongOpt(), option.getValue());
            }
        } catch (ParseException ex) {
            IOUtils.write("Error: " + ex.getMessage() + "\n", System.err);
            printUsageMessage(System.err, options);
            throw ex;
        }
    }

    /**
     * Generate the fixture.
     */
    public abstract CodahaleMetricDefinitionFixture generateFixture() throws Exception;

    /**
     * Writes usage message to 'stream'.
     *
     * @param stream output stream.
     * @throws UnsupportedEncodingException
     */
    public static void printUsageMessage(OutputStream stream, Options options) throws UnsupportedEncodingException {
        PrintWriter writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(stream, "UTF-8")));
        try {
            String header = "Mgmt Metric Schema Generator";
            String footer = "";
            HelpFormatter formatter = new HelpFormatter();
            formatter.printHelp(writer, HelpFormatter.DEFAULT_WIDTH, "schema generator", header, options,
                    HelpFormatter.DEFAULT_LEFT_PAD, HelpFormatter.DEFAULT_DESC_PAD, footer, true); // auto-usage: whether to also show
                                                                                                                                                                                                 // the command line args on the usage line.
        } finally {
            writer.close();
        }
    }
}