stresso/src/main/java/stresso/trie/NodeObserver.java

/*
 * 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 stresso.trie;

import java.util.Map;

import org.apache.fluo.api.client.TransactionBase;
import org.apache.fluo.api.data.Bytes;
import org.apache.fluo.api.data.Column;
import org.apache.fluo.api.observer.Observer;
import org.apache.fluo.recipes.core.types.TypedSnapshotBase.Value;
import org.apache.fluo.recipes.core.types.TypedTransactionBase;

/**
 * Observer that looks for count:wait for nodes. If found, it increments count:seen and increments
 * count:wait of parent node in trie
 */
public class NodeObserver implements Observer {

  private final int stopLevel;

  public NodeObserver(int stopLevel) {
    this.stopLevel = stopLevel;
  }

  @Override
  public void process(TransactionBase tx, Bytes row, Column col) throws Exception {

    final TypedTransactionBase ttx = Constants.TYPEL.wrap(tx);

    Map<Column, Value> colVals =
        ttx.get().row(row).columns(Constants.COUNT_SEEN_COL, Constants.COUNT_WAIT_COL);

    final Integer childWait = colVals.get(Constants.COUNT_WAIT_COL).toInteger(0);

    if (childWait > 0) {
      Integer childSeen = colVals.get(Constants.COUNT_SEEN_COL).toInteger(0);

      ttx.mutate().row(row).col(Constants.COUNT_SEEN_COL).set(childSeen + childWait);
      ttx.mutate().row(row).col(Constants.COUNT_WAIT_COL).delete();

      Node node = new Node(row.toString());
      if (node.getLevel() > stopLevel) {
        Node parent = node.getParent();
        Integer parentWait =
            ttx.get().row(parent.getRowId()).col(Constants.COUNT_WAIT_COL).toInteger(0);
        ttx.mutate().row(parent.getRowId()).col(Constants.COUNT_WAIT_COL)
            .set(parentWait + childWait);
      }

    }
  }
}