heron/api/src/java/com/twitter/heron/api/topology/OutputFieldsGetter.java

// Copyright 2016 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.api.topology;

import java.util.HashMap;
import java.util.Map;

import com.twitter.heron.api.generated.TopologyAPI;
import com.twitter.heron.api.tuple.Fields;
import com.twitter.heron.api.utils.Utils;

public class OutputFieldsGetter implements OutputFieldsDeclarer {
  private Map<String, TopologyAPI.StreamSchema.Builder> fields =
      new HashMap<String, TopologyAPI.StreamSchema.Builder>();

  public void declare(Fields pFields) {
    declare(false, pFields);
  }

  public void declare(boolean direct, Fields pFields) {
    declareStream(Utils.DEFAULT_STREAM_ID, direct, pFields);
  }

  public void declareStream(String streamId, Fields pFields) {
    declareStream(streamId, false, pFields);
  }

  public void declareStream(String streamId, boolean direct, Fields pFields) {
    if (fields.containsKey(streamId)) {
      throw new IllegalArgumentException("Fields for " + streamId + " already set");
    }
    TopologyAPI.StreamSchema.Builder bldr = TopologyAPI.StreamSchema.newBuilder();
    for (int i = 0; i < pFields.size(); ++i) {
      TopologyAPI.StreamSchema.KeyType.Builder ktBldr =
          TopologyAPI.StreamSchema.KeyType.newBuilder();
      ktBldr.setKey(pFields.get(i));
      ktBldr.setType(TopologyAPI.Type.OBJECT);
      bldr.addKeys(ktBldr);
    }
    fields.put(streamId, bldr);
  }


  public Map<String, TopologyAPI.StreamSchema.Builder> getFieldsDeclaration() {
    return fields;
  }
}