org.neo4j.cypher.internal.logical.plans.Prober.scala Maven / Gradle / Ivy

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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.neo4j.cypher.internal.logical.plans

import org.neo4j.cypher.internal.logical.plans.Prober.Probe
import org.neo4j.cypher.internal.util.attribution.IdGen

/**
 * Install a probe to observe data flowing through the query
 *
 * NOTE: This plan is only for testing
 */
case class Prober(override val source: LogicalPlan, probe: Probe)(implicit idGen: IdGen) extends LogicalUnaryPlan(idGen)  {

  override def withLhs(newLHS: LogicalPlan)(idGen: IdGen): LogicalUnaryPlan = copy(source = newLHS)(idGen)

  val availableSymbols: Set[String] = source.availableSymbols
}

object Prober {
  trait Probe {
    /**
     * Called on each row that passes through this operator.
     *
     * NOTE: The row object is transient and any data that needs to be stored
     * should be copied before the call returns.
     *
     * @param row a CypherRow representation
     */
    def onRow(row: AnyRef): Unit

    /**
     * A name to identify the prober in debug information.
     * E.g. in pipelined runtime, the name will be included in the WorkIdentity.workDescription of the operator
     */
    def name: String = ""
  }

  object NoopProbe extends Probe {
    override def onRow(row: AnyRef): Unit = {}
  }
}