org.opencypher.v9_0.util.attribution.Ids.scala Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of util-9.0 Show documentation

Cypher utilities

The newest version!

/*
 * Copyright (c) Neo4j Sweden AB (http://neo4j.com)
 *
 * 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 org.opencypher.v9_0.util.attribution

case class Id(x: Int) extends AnyVal

object Id {
  val INVALID_ID: Id = Id(-1)
}

/**
 * Generates IDs
 */
trait IdGen {
  /**
   * @return an ID
   */
  def id(): Id
}

/**
 * Generates IDs in sequence starting at `initialValue`
 */
class SequentialIdGen(initialValue: Int = 0) extends IdGen {
  private var i: Int = initialValue

  def id(): Id = {
    val id = Id(i)
    i += 1
    id
  }
}

/**
 * Generates only the given ID.
 */
case class SameId(id: Id) extends IdGen

/**
 * An entity that is defined by its ID.
 */
trait Identifiable {
  /**
   * @return the ID of the entity.
   */
  def id: Id
}