Initial hash code identifier support #27

We use a SHA-256 hash based on the binary object stream of serializables.
We provide two difference classes for SutStates and Actions which can
get more properties in the future.

src/main/scala/de/retest/guistatemachine/api/ActionIdentifier.scala

@@ -0,0 +1,5 @@
+package de.retest.guistatemachine.api
+
+import de.retest.surili.commons.actions.Action
+
+class ActionIdentifier(action: Action) extends HashIdentifier(action)

src/main/scala/de/retest/guistatemachine/api/GuiStateMachine.scala

@@ -13,13 +13,15 @@ import de.retest.surili.commons.actions.Action
   */
 trait GuiStateMachine {
 
+  def getState(sutStateIdentifier: SutStateIdentifier): State
+
   /**
     * Gets a state identified by the corresponding SUT state.
     *
     * @param sutState The SUT state which identifies the state.
     * @return The state identified by the descriptors. If there has not been any state yet, it will be added.
     */
-  def getState(sutState: SutState): State
+  def getState(sutState: SutState): State = getState(new SutStateIdentifier(sutState))
 
   /**
     * Executes an action from a state leading to the current state described by descriptors.
@@ -29,26 +31,27 @@ trait GuiStateMachine {
     * @param to The state which the execution leads to.
     * @return The current state which the transition of a leads to.
     */
-  def executeAction(from: State, a: Action, to: State): State
+  def executeAction(from: State, a: ActionIdentifier, to: State): State
+  def executeAction(from: State, a: Action, to: State): State = executeAction(from, new ActionIdentifier(a), to)
   def executeAction(fromSutState: SutState, a: Action, toSutState: SutState): State =
     executeAction(getState(fromSutState), a, getState(toSutState))
 
-  def getAllStates: Map[SutState, State]
+  def getAllStates: Map[SutStateIdentifier, State]
 
   /**
     * In the legacy code this was only used to show the number of actions which have been explored by Monkey Testing.
     *
     * @return All actions which have been explored and therefore have a corresponding transition.
     */
-  def getAllExploredActions: Set[Action]
+  def getAllExploredActions: Set[ActionIdentifier]
 
   /**
     * In the legacy code this was only used to calculate all never explored actions.
     * It could be used for the visualization of the NFA to see how often actions are executed.
     *
     * @return The number of times every explored action has been executed in the NFA. Never explored actions are not part of it.
     */
-  def getActionExecutionTimes: Map[Action, Int]
+  def getActionExecutionTimes: Map[ActionIdentifier, Int]
 
   /**
     * Clears all states, transitions and never explored actions etc.

src/main/scala/de/retest/guistatemachine/api/HashIdentifier.scala

@@ -0,0 +1,44 @@
+package de.retest.guistatemachine.api
+
+import java.io.{ByteArrayOutputStream, ObjectOutputStream, Serializable}
+
+/**
+  * Storing the whole states and actions as XML takes too much space. Therefore, we only store a hash value. The hash
+  * should have no collisions to uniquely identify states and actions. Since we use SHA-256 the probability is very low
+  * that any collisions will occur.
+  *
+  * @param serializable The serializable from which a SHA-256 is generated.
+  */
+@SerialVersionUID(1L)
+class HashIdentifier(serializable: Serializable) extends scala.Serializable {
+  val hash: String = HashIdentifier.sha256Hash(HashIdentifier.serializableToString(serializable))
+
+  override def equals(obj: Any): Boolean =
+    if (!obj.isInstanceOf[HashIdentifier]) {
+      false
+    } else {
+      val other = obj.asInstanceOf[HashIdentifier]
+      hash.equals(other.hash)
+    }
+
+  override def hashCode(): Int = hash.hashCode
+
+  override def toString: String = s"hash=$hash"
+
+}
+
+object HashIdentifier {
+  def sha256Hash(text: String): String =
+    String.format("%064x", new java.math.BigInteger(1, java.security.MessageDigest.getInstance("SHA-256").digest(text.getBytes("UTF-8"))))
+
+  def serializableToString(serializable: Serializable): String = {
+    val byteArrayOutputStream = new ByteArrayOutputStream()
+    val oos = new ObjectOutputStream(byteArrayOutputStream)
+    try {
+      oos.writeObject(serializable)
+      byteArrayOutputStream.toString("UTF-8")
+    } finally {
+      oos.close()
+    }
+  }
+}

src/main/scala/de/retest/guistatemachine/api/State.scala

@@ -1,8 +1,5 @@
 package de.retest.guistatemachine.api
 
-import de.retest.recheck.ui.descriptors.SutState
-import de.retest.surili.commons.actions.Action
-
 /**
   * A state should be identified by its corresponding SutState.
   * It consists of actions which have not been explored yet and transitions to states which build up the state machine.
@@ -12,19 +9,19 @@ trait State {
   /**
     * @return The SutState which identifies this state.
     */
-  def getSutState: SutState
+  def getSutStateIdentifier: SutStateIdentifier
 
   /**
     * NFA states can lead to different states by consuming the same symbol.
     * Hence, we have a set of states per action.
     * In the legacy code there was a type called `AmbigueState` but a multimap simplifies the implementation.
     */
-  def getOutgoingActionTransitions: Map[Action, ActionTransitions]
+  def getOutgoingActionTransitions: Map[ActionIdentifier, ActionTransitions]
 
   /**
     * Helper method to retrieve all incoming transitions.
     */
-  def getIncomingActionTransitions: Map[Action, ActionTransitions]
+  def getIncomingActionTransitions: Map[ActionIdentifier, ActionTransitions]
 
   /**
     * Overriding this method is required to allow the usage of a set of states.
@@ -34,15 +31,15 @@ trait State {
   override def equals(obj: Any): Boolean = {
     obj match {
       case other: State =>
-        this.getSutState == other.getSutState
+        this.getSutStateIdentifier == other.getSutStateIdentifier
       case _ =>
         super.equals(obj)
     }
   }
 
-  override def hashCode(): Int = this.getSutState.hashCode()
+  override def hashCode(): Int = this.getSutStateIdentifier.hashCode()
 
-  override def toString: String = s"sutState=$getSutState,transitions=$getOutgoingActionTransitions"
+  override def toString: String = s"sutStateIdentifier=$getSutStateIdentifier"
 
   /**
     * Adds a new transition to the state which is only allowed by calling the methods of [[GuiStateMachine]].
@@ -51,5 +48,5 @@ trait State {
     * @param to The state which the transition leads t o.
     * @return The number of times the action has been executed from this state. The target state does not matter for this number.
     */
-  private[api] def addTransition(a: Action, to: State): Int
+  private[api] def addTransition(a: ActionIdentifier, to: State): Int
 }

src/main/scala/de/retest/guistatemachine/api/SutStateIdentifier.scala

@@ -0,0 +1,5 @@
+package de.retest.guistatemachine.api
+
+import de.retest.recheck.ui.descriptors.SutState
+
+class SutStateIdentifier(sutState: SutState) extends HashIdentifier(sutState)

src/main/scala/de/retest/guistatemachine/api/impl/GuiStateMachineImpl.scala

@@ -1,9 +1,7 @@
 package de.retest.guistatemachine.api.impl
 
 import com.typesafe.scalalogging.Logger
-import de.retest.guistatemachine.api.{GuiStateMachine, State}
-import de.retest.recheck.ui.descriptors.SutState
-import de.retest.surili.commons.actions.Action
+import de.retest.guistatemachine.api.{ActionIdentifier, GuiStateMachine, State, SutStateIdentifier}
 
 import scala.collection.immutable.{HashMap, HashSet}
 
@@ -13,31 +11,31 @@ import scala.collection.immutable.{HashMap, HashSet}
 @SerialVersionUID(1L)
 class GuiStateMachineImpl extends GuiStateMachine with Serializable {
   @transient private val logger = Logger[GuiStateMachineImpl]
-  private var states = new HashMap[SutState, State]
+  private var states = new HashMap[SutStateIdentifier, State]
 
   /**
     * The legacy code stored execution counters for every action.
     */
-  private var allExploredActions = new HashSet[Action]
+  private var allExploredActions = new HashSet[ActionIdentifier]
 
   /**
     * `actionExecutionCounter` from the legacy code.
     * Stores the total number of executions per action.
     */
-  private var actionExecutionTimes = new HashMap[Action, Int]
+  private var actionExecutionTimes = new HashMap[ActionIdentifier, Int]
 
-  override def getState(sutState: SutState): State = this.synchronized {
+  override def getState(sutState: SutStateIdentifier): State = this.synchronized {
     if (states.contains(sutState)) {
       states(sutState)
     } else {
-      logger.info(s"Create new state from SUT state with hash code ${sutState.hashCode()}")
+      logger.info(s"Create new state from SUT state $sutState")
       val s = StateImpl(sutState)
       states += (sutState -> s)
       s
     }
   }
 
-  override def executeAction(from: State, a: Action, to: State): State = this.synchronized {
+  override def executeAction(from: State, a: ActionIdentifier, to: State): State = this.synchronized {
     allExploredActions += a
     val old = actionExecutionTimes.get(a)
     old match {
@@ -48,16 +46,16 @@ class GuiStateMachineImpl extends GuiStateMachine with Serializable {
     to
   }
 
-  override def getAllStates: Map[SutState, State] = this.synchronized { states }
+  override def getAllStates: Map[SutStateIdentifier, State] = this.synchronized { states }
 
-  override def getAllExploredActions: Set[Action] = this.synchronized { allExploredActions }
+  override def getAllExploredActions: Set[ActionIdentifier] = this.synchronized { allExploredActions }
 
-  override def getActionExecutionTimes: Map[Action, Int] = this.synchronized { actionExecutionTimes }
+  override def getActionExecutionTimes: Map[ActionIdentifier, Int] = this.synchronized { actionExecutionTimes }
 
   override def clear(): Unit = this.synchronized {
-    states = new HashMap[SutState, State]
-    allExploredActions = new HashSet[Action]
-    actionExecutionTimes = new HashMap[Action, Int]
+    states = new HashMap[SutStateIdentifier, State]
+    allExploredActions = new HashSet[ActionIdentifier]
+    actionExecutionTimes = new HashMap[ActionIdentifier, Int]
   }
 
   override def assignFrom(other: GuiStateMachine): Unit = this.synchronized {

src/main/scala/de/retest/guistatemachine/api/impl/StateImpl.scala

@@ -1,30 +1,28 @@
 package de.retest.guistatemachine.api.impl
 
-import de.retest.guistatemachine.api.{ActionTransitions, State}
-import de.retest.recheck.ui.descriptors.SutState
-import de.retest.surili.commons.actions.Action
+import de.retest.guistatemachine.api.{ActionIdentifier, ActionTransitions, State, SutStateIdentifier}
 
 import scala.collection.immutable.HashMap
 
 @SerialVersionUID(1L)
-case class StateImpl(sutState: SutState) extends State with Serializable {
+case class StateImpl(sutState: SutStateIdentifier) extends State with Serializable {
 
   /**
     * Currently, there is no MultiMap trait for immutable maps in the Scala standard library.
     * The legacy code used `AmbigueState` here which was more complicated than just a multi map.
     */
-  private var outgoingActionTransitions = HashMap[Action, ActionTransitions]()
+  private var outgoingActionTransitions = HashMap[ActionIdentifier, ActionTransitions]()
 
   /**
     * Redundant information but helpful to be retrieved.
     */
-  private var incomingActionTransitions = HashMap[Action, ActionTransitions]()
+  private var incomingActionTransitions = HashMap[ActionIdentifier, ActionTransitions]()
 
-  override def getSutState: SutState = this.synchronized { sutState }
-  override def getOutgoingActionTransitions: Map[Action, ActionTransitions] = this.synchronized { outgoingActionTransitions }
-  override def getIncomingActionTransitions: Map[Action, ActionTransitions] = this.synchronized { incomingActionTransitions }
+  override def getSutStateIdentifier: SutStateIdentifier = this.synchronized { sutState }
+  override def getOutgoingActionTransitions: Map[ActionIdentifier, ActionTransitions] = this.synchronized { outgoingActionTransitions }
+  override def getIncomingActionTransitions: Map[ActionIdentifier, ActionTransitions] = this.synchronized { incomingActionTransitions }
 
-  private[api] override def addTransition(a: Action, to: State): Int = {
+  private[api] override def addTransition(a: ActionIdentifier, to: State): Int = {
     val executionCounter = this.synchronized {
       outgoingActionTransitions.get(a) match {
         case Some(oldTransitions) =>

src/main/scala/de/retest/guistatemachine/api/impl/serialization/GraphActionEdge.scala

@@ -1,7 +1,6 @@
 package de.retest.guistatemachine.api.impl.serialization
-import de.retest.recheck.ui.descriptors.SutState
-import de.retest.surili.commons.actions.Action
+import de.retest.guistatemachine.api.{ActionIdentifier, SutStateIdentifier}
 
-case class GraphActionEdge(from: SutState, to: SutState, action: Action) {
+case class GraphActionEdge(from: SutStateIdentifier, to: SutStateIdentifier, action: ActionIdentifier) {
   override def toString: String = action.toString
 }

src/main/scala/de/retest/guistatemachine/api/impl/serialization/GraphicsProvider.scala

@@ -3,15 +3,15 @@ package de.retest.guistatemachine.api.impl.serialization
 import java.awt.Color
 
 import com.github.systemdir.gml.model.{EdgeGraphicDefinition, GraphicDefinition, NodeGraphicDefinition, YedGmlGraphicsProvider}
-import de.retest.recheck.ui.descriptors.SutState
+import de.retest.guistatemachine.api.SutStateIdentifier
 
-class GraphicsProvider extends YedGmlGraphicsProvider[SutState, GraphActionEdge, AnyRef] {
-  override def getVertexGraphics(vertex: SutState): NodeGraphicDefinition =
+class GraphicsProvider extends YedGmlGraphicsProvider[SutStateIdentifier, GraphActionEdge, AnyRef] {
+  override def getVertexGraphics(vertex: SutStateIdentifier): NodeGraphicDefinition =
     new NodeGraphicDefinition.Builder().setFill(Color.LIGHT_GRAY).setLineColor(Color.black).setFontStyle(GraphicDefinition.FontStyle.ITALIC).build
-  override def getEdgeGraphics(edge: GraphActionEdge, edgeSource: SutState, edgeTarget: SutState): EdgeGraphicDefinition =
+  override def getEdgeGraphics(edge: GraphActionEdge, edgeSource: SutStateIdentifier, edgeTarget: SutStateIdentifier): EdgeGraphicDefinition =
     new EdgeGraphicDefinition.Builder()
       .setTargetArrow(EdgeGraphicDefinition.ArrowType.SHORT_ARROW)
       .setLineType(GraphicDefinition.LineType.DASHED)
       .build
-  override def getGroupGraphics(group: AnyRef, groupElements: java.util.Set[SutState]): NodeGraphicDefinition = null
+  override def getGroupGraphics(group: AnyRef, groupElements: java.util.Set[SutStateIdentifier]): NodeGraphicDefinition = null
 }

src/main/scala/de/retest/guistatemachine/api/impl/serialization/GuiStateMachinGMLSerializer.scala

@@ -2,13 +2,12 @@ package de.retest.guistatemachine.api.impl.serialization
 import java.io.{BufferedWriter, File, FileOutputStream, OutputStreamWriter}
 
 import com.github.systemdir.gml.YedGmlWriter
-import de.retest.guistatemachine.api.{GuiStateMachine, GuiStateMachineSerializer}
-import de.retest.recheck.ui.descriptors.SutState
+import de.retest.guistatemachine.api.{GuiStateMachine, GuiStateMachineSerializer, SutStateIdentifier}
 import org.jgrapht.graph.DirectedPseudograph
 
 class GuiStateMachinGMLSerializer(guiStateMachine: GuiStateMachine) extends GuiStateMachineSerializer {
 
-  type GraphType = DirectedPseudograph[SutState, GraphActionEdge]
+  type GraphType = DirectedPseudograph[SutStateIdentifier, GraphActionEdge]
 
   /**
     * Converts the state machines into GML which can be read by editors like yED.
@@ -25,9 +24,9 @@ class GuiStateMachinGMLSerializer(guiStateMachine: GuiStateMachine) extends GuiS
 
     // get the gml writer
     val writer =
-      new YedGmlWriter.Builder[SutState, GraphActionEdge, AnyRef](graphicsProvider, YedGmlWriter.PRINT_LABELS: _*)
+      new YedGmlWriter.Builder[SutStateIdentifier, GraphActionEdge, AnyRef](graphicsProvider, YedGmlWriter.PRINT_LABELS: _*)
         .setEdgeLabelProvider(_.toString)
-        .setVertexLabelProvider(sutState => "%s - hash code: %d".format(sutState.toString, sutState.hashCode()))
+        .setVertexLabelProvider(_.toString)
         .build
 
     // write to file
@@ -54,7 +53,7 @@ class GuiStateMachinGMLSerializer(guiStateMachine: GuiStateMachine) extends GuiS
         val actionTransitions = transition._2
         val action = transition._1
         actionTransitions.states.foreach { toState =>
-          val toVertex = toState.getSutState
+          val toVertex = toState.getSutStateIdentifier
           val edge = GraphActionEdge(fromVertex, toVertex, action)
           if (!graph.addEdge(fromVertex, toVertex, edge)) { throw new RuntimeException(s"Failed to add edge $edge") }
         }

src/test/scala/de/retest/guistatemachine/api/AbstractApiSpec.scala

@@ -8,7 +8,7 @@ import org.scalatest.{Matchers, WordSpec}
 
 abstract trait AbstractApiSpec extends WordSpec with Matchers {
 
-  def createSutState(rootElements: RootElement*) : SutState = new SutState(Arrays.asList(rootElements: _*))
+  def createSutState(rootElements: RootElement*): SutState = new SutState(Arrays.asList(rootElements: _*))
 
   /**
     * Creates a new identifying attributes collection which should only match other identifying attributes with the same ID.

src/test/scala/de/retest/guistatemachine/api/HashIdentifierSpec.scala

@@ -0,0 +1,27 @@
+package de.retest.guistatemachine.api
+
+import de.retest.surili.commons.actions.NavigateToAction
+
+class HashIdentifierSpec extends AbstractApiSpec {
+  private val action0 = new NavigateToAction("http://google.com")
+  private val action0Identifier = new HashIdentifier(action0)
+  private val action1 = new NavigateToAction("http://wikipedia.org")
+  private val action1Identifier = new HashIdentifier(action1)
+
+  "HashIdentifier" should {
+    "generate SHA hashes" in {
+      action0Identifier.hash shouldEqual "fd00ea22cb50efd96c3ff59d8900685d0d64f2cee1e77873133e7e186afd2e7f"
+      action1Identifier.hash shouldEqual "240d08498736de4d893c146fd64b58b1ae1eda8c36a565919b035d86c6ee2084"
+    }
+
+    "not equal" in {
+      action0Identifier.equals(action1Identifier) shouldEqual false
+      action0Identifier.hashCode() should not equal action1Identifier.hashCode()
+    }
+
+    "equal" in {
+      action0Identifier.equals(action0Identifier) shouldEqual true
+      action0Identifier.hashCode() shouldEqual action0Identifier.hashCode()
+    }
+  }
+}