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 org.apache.beam.sdk.extensions.sql.impl.planner;
  
  import com.google.auto.value.AutoValue;
  
  /** This is a utility class to represent rowCount, rate and window. */
  @AutoValue
  public abstract class NodeStats {
  
    /**
     * Returns an instance with all values set to INFINITY. This will be only used when the node is
     * not a BeamRelNode and we don't have an estimation implementation for it in the metadata
     * handler. In this case we return INFINITE and it will be propagated up in the estimates.
     */
    public static final NodeStats UNKNOWN =
        create(Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY);
  
    public abstract double getRowCount();
  
    public abstract double getRate();
  
    /**
     * This method returns the number of tuples in each window. It is different than the windowing
     * notion of Beam.
     */
    public abstract double getWindow();
  
    public static NodeStats create(double rowCount, double rate, double window) {
      if (window < 0 || rate < 0 || rowCount < 0) {
        throw new IllegalArgumentException("All the estimates in NodeStats should be positive");
      }
      return new AutoValue_NodeStats(rowCount, rate, window);
    }
  
    /** It creates an instance with rate=0 and window=rowCount for bounded sources. */
    public static NodeStats create(double rowCount) {
      return create(rowCount, 0d, rowCount);
    }
  
    /** If any of the values for rowCount, rate or window is infinite, it returns true. */
    public boolean isUnknown() {
      return Double.isInfinite(getRowCount())
          || Double.isInfinite(getRate())
          || Double.isInfinite(getWindow());
    }
  
    public NodeStats multiply(double factor) {
      return create(getRowCount() * factor, getRate() * factor, getWindow() * factor);
    }
  
    public NodeStats plus(NodeStats that) {
      if (this.isUnknown() || that.isUnknown()) {
        return UNKNOWN;
      }
      return create(
          this.getRowCount() + that.getRowCount(),
          this.getRate() + that.getRate(),
          this.getWindow() + that.getWindow());
    }
  
    public NodeStats minus(NodeStats that) {
      if (this.isUnknown() || that.isUnknown()) {
        return UNKNOWN;
      }
      return create(
          Math.max(this.getRowCount() - that.getRowCount(), 0),
          Math.max(this.getRate() - that.getRate(), 0),
          Math.max(this.getWindow() - that.getWindow(), 0));
    }
  }
  