heron/tools/apiserver/src/java/com/twitter/heron/apiserver/resources/HeronResource.java

//  Copyright 2017 Twitter. 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 com.twitter.heron.apiserver.resources;

import javax.servlet.ServletContext;
import javax.ws.rs.core.Context;

import com.twitter.heron.spi.common.Config;

public class HeronResource {

  public static final String ATTRIBUTE_CLUSTER = "cluster";
  public static final String ATTRIBUTE_CONFIGURATION = "configuration";
  public static final String ATTRIBUTE_CONFIGURATION_DIRECTORY = "configuration_directory";
  public static final String ATTRIBUTE_CONFIGURATION_OVERRIDE_PATH = "configuration_override";
  public static final String ATTRIBUTE_PORT = "port";
  public static final String ATTRIBUTE_DOWNLOAD_HOSTNAME = "download_hostname";

  @Context
  protected ServletContext servletContext;

  private Config baseConfiguration;
  private String configurationDirectory;
  private String configurationOverridePath;
  private String cluster;
  private String port;
  private String downloadHostname;

  Config getBaseConfiguration() {
    if (baseConfiguration == null) {
      baseConfiguration = (Config) servletContext.getAttribute(ATTRIBUTE_CONFIGURATION);
    }
    return baseConfiguration;
  }

  String getConfigurationDirectory() {
    if (configurationDirectory == null) {
      configurationDirectory =
          (String) servletContext.getAttribute(ATTRIBUTE_CONFIGURATION_DIRECTORY);
    }
    return configurationDirectory;
  }

  String getConfigurationOverridePath() {
    if (configurationOverridePath == null) {
      configurationOverridePath =
          (String) servletContext.getAttribute(ATTRIBUTE_CONFIGURATION_OVERRIDE_PATH);
    }

    return configurationOverridePath;
  }

  String getCluster() {
    if (cluster == null) {
      cluster = (String) servletContext.getAttribute(ATTRIBUTE_CLUSTER);
    }

    return cluster;
  }

  String getPort() {
    if (port == null) {
      port = (String) servletContext.getAttribute(ATTRIBUTE_PORT);
    }

    return port;
  }

  String getDownloadHostName() {
    if (downloadHostname == null) {
      downloadHostname = (String) servletContext.getAttribute(ATTRIBUTE_DOWNLOAD_HOSTNAME);
    }

    return downloadHostname;
  }

}