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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.expressions.Expression
import org.neo4j.cypher.internal.expressions.LogicalVariable
import org.neo4j.cypher.internal.expressions.RelTypeName
import org.neo4j.cypher.internal.expressions.SemanticDirection
import org.neo4j.cypher.internal.ir.VarPatternLength
import org.neo4j.cypher.internal.util.attribution.IdGen
/**
* For every source row, traverse all the relationships of 'from' which fulfill the
* provided constraints. Produce one row per traversed relationships, and add the
* relationship and end node as values on the produced rows.
*/
case class Expand(override val source: LogicalPlan,
from: String,
dir: SemanticDirection,
types: Seq[RelTypeName],
to: String,
relName: String,
mode: ExpansionMode = ExpandAll)
(implicit idGen: IdGen)
extends LogicalUnaryPlan(idGen) {
override def withLhs(newLHS: LogicalPlan)(idGen: IdGen): LogicalUnaryPlan = copy(source = newLHS)(idGen)
override val availableSymbols: Set[String] = source.availableSymbols + relName + to
}
/**
* This works exactly like Expand, but if no matching relationships are found, a single
* row is produced instead populated by the argument, and the 'relName' and 'to' variables
* are set to NO_VALUE.
*/
case class OptionalExpand(override val source: LogicalPlan,
from: String,
dir: SemanticDirection,
types: Seq[RelTypeName],
to: String,
relName: String,
mode: ExpansionMode = ExpandAll,
predicate: Option[Expression] = None)
(implicit idGen: IdGen)
extends LogicalUnaryPlan(idGen) {
override def withLhs(newLHS: LogicalPlan)(idGen: IdGen): LogicalUnaryPlan = copy(source = newLHS)(idGen)
override val availableSymbols: Set[String] = source.availableSymbols + relName + to
}
/**
* For every source row, explore all homogeneous paths starting in 'from', that fulfill the provided
* criteria. Paths are homogeneous in that all relationships have to fulfill the same relationship
* predicate, and all nodes have to fulfill the same node predicate. For each explored
* path that is longer or equal to length.min, and shorter than length.max, a row is produced.
*
* The relationships and end node of the corresponding path are added to the produced row.
*/
case class VarExpand(override val source: LogicalPlan,
from: String,
dir: SemanticDirection,
projectedDir: SemanticDirection,
types: Seq[RelTypeName],
to: String,
relName: String,
length: VarPatternLength,
mode: ExpansionMode = ExpandAll,
nodePredicate: Option[VariablePredicate] = None,
relationshipPredicate: Option[VariablePredicate] = None)
(implicit idGen: IdGen) extends LogicalUnaryPlan(idGen) {
override def withLhs(newLHS: LogicalPlan)(idGen: IdGen): LogicalUnaryPlan = copy(source = newLHS)(idGen)
override val availableSymbols: Set[String] = source.availableSymbols + relName + to
}
/**
* In essence a VarExpand, where some paths are not explored if they could not produce an unseen
* end node. Used to serve DISTINCT VarExpands where the individual paths are not of interest. This
* operator does not guarantee unique end nodes, but it will produce less of them than the regular
* VarExpand.
*
* Only the end node is added to produced rows.
*/
case class PruningVarExpand(override val source: LogicalPlan,
from: String,
dir: SemanticDirection,
types: Seq[RelTypeName],
to: String,
minLength: Int,
maxLength: Int,
nodePredicate: Option[VariablePredicate] = None,
relationshipPredicate: Option[VariablePredicate] = None)
(implicit idGen: IdGen)
extends LogicalUnaryPlan(idGen) {
override def withLhs(newLHS: LogicalPlan)(idGen: IdGen): LogicalUnaryPlan = copy(source = newLHS)(idGen)
override val availableSymbols: Set[String] = source.availableSymbols + to
}
sealed trait ExpansionMode
/**
* Expand relationships (a)-[r]-(b) for a given a, and populate r and b
*/
case object ExpandAll extends ExpansionMode
/**
* Expand relationships (a)-[r]-(b) for a given a and b, and populate r
*/
case object ExpandInto extends ExpansionMode
case class VariablePredicate(variable: LogicalVariable, predicate: Expression)
