content: /**
   * 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 storm.trident.util;
  
  import backtype.storm.generated.StreamInfo;
  import backtype.storm.topology.IComponent;
  import backtype.storm.topology.OutputFieldsGetter;
  import backtype.storm.tuple.Fields;
  import backtype.storm.utils.Utils;
  
  import org.apache.thrift.TBase;
  import org.apache.thrift.TDeserializer;
  import org.apache.thrift.TException;
  import org.apache.thrift.TSerializer;
  import org.jgrapht.DirectedGraph;
  
  import java.util.*;
  
  public class TridentUtils {
      public static Fields fieldsUnion(Fields... fields) {
          Set<String> ret = new HashSet<String>();
          for(Fields f: fields) {
              if(f!=null) ret.addAll(f.toList());
          }
          return new Fields(new ArrayList<String>(ret));
      }
      
      public static Fields fieldsConcat(Fields... fields) {
          List<String> ret = new ArrayList<String>();
          for(Fields f: fields) {
              if(f!=null) ret.addAll(f.toList());
          }
          return new Fields(ret);
      }
      
      public static Fields fieldsSubtract(Fields all, Fields minus) {
          Set<String> removeSet = new HashSet<String>(minus.toList());
          List<String> toKeep = new ArrayList<String>();
          for(String s: all.toList()) {
              if(!removeSet.contains(s)) {
                  toKeep.add(s);
              }
          }
          return new Fields(toKeep);
      }
      
      public static Fields getSingleOutputStreamFields(IComponent component) {
          OutputFieldsGetter getter = new OutputFieldsGetter();
          component.declareOutputFields(getter);
          Map<String, StreamInfo> declaration = getter.getFieldsDeclaration();
          if(declaration.size()!=1) {
              throw new RuntimeException("Trident only supports components that emit a single stream");
          }
          StreamInfo si = declaration.values().iterator().next();
          if(si.is_direct()) {
              throw new RuntimeException("Trident does not support direct streams");
          }
          return new Fields(si.get_output_fields());
      }
      
      /**
       * Assumes edge contains an index
       */
      public static <T> List<T> getParents(DirectedGraph g, T n) {
          List<IndexedEdge> incoming = new ArrayList(g.incomingEdgesOf(n));
          Collections.sort(incoming);
          List<T> ret = new ArrayList();
          for(IndexedEdge e: incoming) {
              ret.add((T)e.source);
          }        
          return ret;
      }
  
      public static <T> List<T> getChildren(DirectedGraph g, T n) {
          List<IndexedEdge> outgoing = new ArrayList(g.outgoingEdgesOf(n));
          List<T> ret = new ArrayList();
          for(IndexedEdge e: outgoing) {
              ret.add((T)e.target);
          }        
          return ret;
      }
      
      
      public static <T> T getParent(DirectedGraph g, T n) {
          List<T> parents = getParents(g, n);
          if(parents.size()!=1) {
              throw new RuntimeException("Expected a single parent");
          }
          return parents.get(0);
      }
      
      public static byte[] thriftSerialize(TBase t) {
          return Utils.thriftSerialize(t);
      }
  
      public static <T> T thriftDeserialize(Class c, byte[] b) {
          return Utils.thriftDeserialize(c,b);
          }
          
  }
  