library/src/main/java/com/datatorrent/lib/streamquery/OuterJoinOperator.java

/*
 * Copyright (c) 2013 DataTorrent, Inc. 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.datatorrent.lib.streamquery;

/**
 * An operator that provides sql left,right and full outer join metric semantics on live stream. <br>
 * <p>
 * Please refer to {@link com.datatorrent.lib.streamquery.InnerJoinOperator} for
 * details.
 *
 * <b> Properties : </b> <br>
 * <b> isLeftJoin : </b> Left join flag. <br>
 * <b> isFullJoin : </b> Full join flag. <br>
 * @displayName Outer Join
 * @category Streamquery
 * @tags sql, outer join operator
 * @since 0.3.4
 */
public class OuterJoinOperator extends InnerJoinOperator
{

  private boolean isLeftJoin = true;
  private boolean isFullJoin = false;

  @Override
  public void endWindow()
  {
    // full outer join
    if (isFullJoin) {
      for (int i = 0; i < table1.size(); i++) {
        boolean merged = false;
        for (int j = 0; j < table2.size(); j++) {
          if ((joinCondition == null)
              || (joinCondition.isValidJoin(table1.get(i), table2.get(j)))) {
            merged = true;
          }
        }
        if (!merged) {
          joinRows(table1.get(i), null);
        }
      }
      for (int i = 0; i < table2.size(); i++) {
        boolean merged = false;
        for (int j = 0; j < table1.size(); j++) {
          if ((joinCondition == null)
              || (joinCondition.isValidJoin(table1.get(j), table2.get(i)))) {
            merged = true;
          }
        }
        if (!merged) { // only output non merged rows
          joinRows(null, table2.get(i));
        }
      }
      return;
    }

    // left or right join
    if (isLeftJoin) {
      for (int i = 0; i < table1.size(); i++) {
        boolean merged = false;
        for (int j = 0; j < table2.size(); j++) {
          if ((joinCondition == null)
              || (joinCondition.isValidJoin(table1.get(i), table2.get(j)))) {
            merged = true;
          }
        }
        if (!merged) {
          joinRows(table1.get(i), null);
        }
      }
    } else {
      for (int i = 0; i < table2.size(); i++) {
        boolean merged = false;
        for (int j = 0; j < table1.size(); j++) {
          if ((joinCondition == null)
              || (joinCondition.isValidJoin(table1.get(j), table2.get(i)))) {
            merged = true;
          }
        }
        if (!merged) { // only output non merged rows
          joinRows(null, table2.get(i));
        }
      }
    }
  }

  public void setLeftJoin()
  {
    isLeftJoin = true;
  }
  public void setRighttJoin()
  {
    isLeftJoin = false;
  }

  public boolean isFullJoin()
  {
    return isFullJoin;
  }

  public void setFullJoin(boolean isFullJoin)
  {
    this.isFullJoin = isFullJoin;
  }
}