From 607ba634fea2c77bb0ff6ee3a8965fc73a1a74e8 Mon Sep 17 00:00:00 2001
From: Ross Nicoll <ross.nicoll@r3cev.com>
Date: Tue, 27 Sep 2016 12:12:15 +0100
Subject: [PATCH] Add filter composition for clauses

---
 .../core/contracts/clauses/AllComposition.kt  |  1 +
 .../core/contracts/clauses/AnyComposition.kt  |  1 +
 .../core/contracts/clauses/FilterOn.kt        | 25 +++++++++++++++++++
 .../contracts/clauses/FirstComposition.kt     |  1 +
 4 files changed, 28 insertions(+)
 create mode 100644 core/src/main/kotlin/com/r3corda/core/contracts/clauses/FilterOn.kt

diff --git a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AllComposition.kt b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AllComposition.kt
index 1deea44fdd..99dc5f528b 100644
--- a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AllComposition.kt
+++ b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AllComposition.kt
@@ -9,6 +9,7 @@ import java.util.*
 /**
  * Compose a number of clauses, such that all of the clauses must run for verification to pass.
  */
+// TODO: Rename to AllOf
 class AllComposition<S : ContractState, C : CommandData, K : Any>(firstClause: Clause<S, C, K>, vararg remainingClauses: Clause<S, C, K>) : CompositeClause<S, C, K>() {
     override val clauses = ArrayList<Clause<S, C, K>>()
 
diff --git a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AnyComposition.kt b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AnyComposition.kt
index 00d7e671f4..a00e95bdd1 100644
--- a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AnyComposition.kt
+++ b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/AnyComposition.kt
@@ -9,6 +9,7 @@ import java.util.*
 /**
  * Compose a number of clauses, such that any number of the clauses can run.
  */
+// TODO: Rename to AnyOf
 class AnyComposition<in S : ContractState, C : CommandData, in K : Any>(vararg rawClauses: Clause<S, C, K>) : CompositeClause<S, C, K>() {
     override val clauses: List<Clause<S, C, K>> = rawClauses.asList()
 
diff --git a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FilterOn.kt b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FilterOn.kt
new file mode 100644
index 0000000000..3574d17593
--- /dev/null
+++ b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FilterOn.kt
@@ -0,0 +1,25 @@
+package com.r3corda.core.contracts.clauses
+
+import com.r3corda.core.contracts.AuthenticatedObject
+import com.r3corda.core.contracts.CommandData
+import com.r3corda.core.contracts.ContractState
+import com.r3corda.core.contracts.TransactionForContract
+
+/**
+ * Filter the states that are passed through to the wrapped clause, to restrict them to a specific type.
+ */
+class FilterOn<S : ContractState, C : CommandData, K : Any>(val clause: Clause<S, C, K>,
+                                                            val filterStates: (List<ContractState>) -> List<S>) : Clause<ContractState, C, K>() {
+    override val requiredCommands: Set<Class<out CommandData>>
+            = clause.requiredCommands
+
+    override fun getExecutionPath(commands: List<AuthenticatedObject<C>>): List<Clause<*, *, *>>
+            = clause.getExecutionPath(commands)
+
+    override fun verify(tx: TransactionForContract,
+                        inputs: List<ContractState>,
+                        outputs: List<ContractState>,
+                        commands: List<AuthenticatedObject<C>>,
+                        groupingKey: K?): Set<C>
+            = clause.verify(tx, filterStates(inputs), filterStates(outputs), commands, groupingKey)
+}
\ No newline at end of file
diff --git a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FirstComposition.kt b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FirstComposition.kt
index 49101c6f84..100234ed32 100644
--- a/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FirstComposition.kt
+++ b/core/src/main/kotlin/com/r3corda/core/contracts/clauses/FirstComposition.kt
@@ -10,6 +10,7 @@ import java.util.*
 /**
  * Compose a number of clauses, such that the first match is run, and it errors if none is run.
  */
+// TODO: Rename to FirstOf
 class FirstComposition<S : ContractState, C : CommandData, K : Any>(val firstClause: Clause<S, C, K>, vararg remainingClauses: Clause<S, C, K>) : CompositeClause<S, C, K>() {
     companion object {
         val logger = loggerFor<FirstComposition<*, *, *>>()