content: /**
   * 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 org.apache.aurora.common.net.http.handlers;
  
  import java.util.Collections;
  import java.util.List;
  
  import javax.ws.rs.GET;
  import javax.ws.rs.Path;
  import javax.ws.rs.Produces;
  import javax.ws.rs.core.MediaType;
  
  import com.google.common.base.Function;
  import com.google.common.base.Joiner;
  import com.google.common.base.Preconditions;
  import com.google.common.base.Supplier;
  import com.google.common.collect.Iterables;
  import com.google.common.collect.Lists;
  import com.google.inject.Inject;
  
  import org.apache.aurora.common.stats.Stat;
  
  /**
   * HTTP handler that prints all registered variables and their current values.
   *
   * @author William Farner
   */
  @Path("/vars")
  public class VarsHandler {
  
    private static final Function<Stat, String> VAR_PRINTER = stat -> stat.getName() + " " + stat.read();
  
    private final Supplier<Iterable<Stat<?>>> statSupplier;
  
    /**
     * Creates a new handler that will report stats from the provided supplier.
     *
     * @param statSupplier Stats supplier.
     */
    @Inject
    public VarsHandler(Supplier<Iterable<Stat<?>>> statSupplier) {
      this.statSupplier = Preconditions.checkNotNull(statSupplier);
    }
  
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String getVars() {
      List<String> lines = Lists.newArrayList(Iterables.transform(statSupplier.get(), VAR_PRINTER));
      Collections.sort(lines);
      return Joiner.on("\n").join(lines);
    }
  }
  