Memoize hashCode results to improve runtime performance when checking policies.

java/arcs/core/data/AccessPath.kt

@@ -19,6 +19,8 @@ typealias StoreId = String
  * Examples of access paths are `input.app.packageName`, `store.rawText`, store.entites[i], etc.
  */
 data class AccessPath(val root: Root, val selectors: List<Selector> = emptyList()) {
+  private val hashCode by lazy { 31 * root.hashCode() + selectors.hashCode() }
+
   /**
    * Constructs an [AccessPath] starting at a connection in [particle] identified
    * by [connectionSpec] followed by [selectors].
@@ -104,4 +106,16 @@ data class AccessPath(val root: Root, val selectors: List<Selector> = emptyList(
     }
     return AccessPath(Root.HandleConnection(particle, root.connectionSpec), selectors)
   }
+
+  override fun equals(other: Any?): Boolean {
+    if (this === other) return true
+    if (other !is AccessPath) return false
+
+    if (root != other.root) return false
+    if (selectors != other.selectors) return false
+
+    return true
+  }
+
+  override fun hashCode(): Int = hashCode
 }

java/arcs/core/data/Recipe.kt

@@ -30,12 +30,26 @@ data class Recipe(
     val spec: ParticleSpec,
     val handleConnections: List<HandleConnection>
   ) {
+    private val hashCode by lazy { 31 * spec.hashCode() + handleConnections.hashCode() }
+
     /** Representation of a handle connection in a particle. */
     data class HandleConnection(
       val spec: HandleConnectionSpec,
       val handle: Handle,
       val type: Type
     )
+
+    override fun equals(other: Any?): Boolean {
+      if (this === other) return true
+      if (other !is Particle) return false
+
+      if (spec != other.spec) return false
+      if (handleConnections != other.handleConnections) return false
+
+      return true
+    }
+
+    override fun hashCode(): Int = hashCode
   }
 
   /** Definition of a handle in a recipe. */
@@ -53,10 +67,40 @@ data class Recipe(
       CREATE, USE, MAP, COPY, JOIN
     }
 
+    private val hashCode by lazy {
+      var result = name.hashCode()
+      result = 31 * result + fate.hashCode()
+      result = 31 * result + type.hashCode()
+      result = 31 * result + (storageKey?.hashCode() ?: 0)
+      result = 31 * result + annotations.hashCode()
+      result = 31 * result + associatedHandles.hashCode()
+      result = 31 * result + id.hashCode()
+      result = 31 * result + tags.hashCode()
+      result
+    }
+
     val capabilities: Capabilities
       get() {
         return Capabilities.fromAnnotations(annotations)
       }
+
+    override fun equals(other: Any?): Boolean {
+      if (this === other) return true
+      if (other !is Handle) return false
+
+      if (name != other.name) return false
+      if (fate != other.fate) return false
+      if (type != other.type) return false
+      if (storageKey != other.storageKey) return false
+      if (annotations != other.annotations) return false
+      if (associatedHandles != other.associatedHandles) return false
+      if (id != other.id) return false
+      if (tags != other.tags) return false
+
+      return true
+    }
+
+    override fun hashCode(): Int = hashCode
   }
 }
 

java/arcs/core/data/Schema.kt

@@ -36,6 +36,14 @@ data class Schema(
   val refinementExpression: Expression<Boolean> = true.asExpr(),
   val queryExpression: Expression<Boolean> = true.asExpr()
 ) {
+  private val hashCode by lazy {
+    var result = names.hashCode()
+    result = 31 * result + fields.hashCode()
+    result = 31 * result + hash.hashCode()
+    result = 31 * result + refinementExpression.hashCode()
+    result = 31 * result + queryExpression.hashCode()
+    result
+  }
 
   /** Ensure instance is registered on construction. */
   init {
@@ -71,6 +79,21 @@ data class Schema(
   fun toString(options: Type.ToStringOptions) =
     names.map { it.name }.plusElement(fields.toString(options)).joinToString(" ")
 
+  override fun equals(other: Any?): Boolean {
+    if (this === other) return true
+    if (other !is Schema) return false
+
+    if (names != other.names) return false
+    if (fields != other.fields) return false
+    if (hash != other.hash) return false
+    if (refinementExpression != other.refinementExpression) return false
+    if (queryExpression != other.queryExpression) return false
+
+    return true
+  }
+
+  override fun hashCode(): Int = hashCode
+
   data class Literal(
     val names: Set<SchemaName>,
     val fields: SchemaFields,