From 6095f6eca9ae96f94d1afdcba9971ac2ec4d8c5b Mon Sep 17 00:00:00 2001
From: Kristóf Marussy <kristof@marussy.com>
Date: Fri, 28 Jun 2024 19:43:52 +0200
Subject: refactor: improve propagation traceability

---
 .../dse/propagation/PropagationRejectedResult.java | 32 ++++++++++++++++++++
 .../store/dse/propagation/PropagationResult.java   | 25 +++++-----------
 .../dse/propagation/PropagationSuccessResult.java  | 34 ++++++++++++++++++++++
 .../impl/rule/BoundPropagationRule.java            |  3 +-
 4 files changed, 76 insertions(+), 18 deletions(-)
 create mode 100644 subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationRejectedResult.java
 create mode 100644 subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationSuccessResult.java

(limited to 'subprojects/store-dse')

diff --git a/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationRejectedResult.java b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationRejectedResult.java
new file mode 100644
index 00000000..6d696de7
--- /dev/null
+++ b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationRejectedResult.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.store.dse.propagation;
+
+public record PropagationRejectedResult(Object reason, String message) implements PropagationResult {
+	@Override
+	public PropagationResult andThen(PropagationResult next) {
+		return this;
+	}
+
+	@Override
+	public boolean isRejected() {
+		return true;
+	}
+
+	@Override
+	public void throwIfRejected() {
+		throw new IllegalArgumentException(formatMessage());
+	}
+
+	public String formatMessage() {
+		return "Propagation failed: %s".formatted(message);
+	}
+
+	@Override
+	public boolean isChanged() {
+		return false;
+	}
+}
diff --git a/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationResult.java b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationResult.java
index ea56653a..e07e443b 100644
--- a/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationResult.java
+++ b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationResult.java
@@ -5,24 +5,15 @@
  */
 package tools.refinery.store.dse.propagation;
 
-public enum PropagationResult {
-	UNCHANGED,
-	PROPAGATED,
-	REJECTED;
+public sealed interface PropagationResult permits PropagationSuccessResult, PropagationRejectedResult {
+	PropagationResult UNCHANGED = PropagationSuccessResult.UNCHANGED;
+	PropagationResult PROPAGATED = PropagationSuccessResult.PROPAGATED;
 
-	public PropagationResult andThen(PropagationResult next) {
-		return switch (this) {
-			case UNCHANGED -> next;
-			case PROPAGATED -> next == REJECTED ? REJECTED : PROPAGATED;
-			case REJECTED -> REJECTED;
-		};
-	}
+	PropagationResult andThen(PropagationResult next);
 
-	public boolean isRejected() {
-		return this == REJECTED;
-	}
+	boolean isRejected();
 
-	public boolean isChanged() {
-		return this == PROPAGATED;
-	}
+	void throwIfRejected();
+
+	boolean isChanged();
 }
diff --git a/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationSuccessResult.java b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationSuccessResult.java
new file mode 100644
index 00000000..22117772
--- /dev/null
+++ b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/PropagationSuccessResult.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.store.dse.propagation;
+
+public enum PropagationSuccessResult implements PropagationResult {
+	UNCHANGED,
+	PROPAGATED;
+
+	@Override
+	public PropagationResult andThen(PropagationResult next) {
+		return switch (this) {
+			case UNCHANGED -> next;
+			case PROPAGATED -> next instanceof PropagationRejectedResult ? next : PROPAGATED;
+		};
+	}
+
+	@Override
+	public boolean isRejected() {
+		return false;
+	}
+
+	@Override
+	public void throwIfRejected() {
+		// Nothing to throw.
+	}
+
+	@Override
+	public boolean isChanged() {
+		return this == PROPAGATED;
+	}
+}
diff --git a/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/impl/rule/BoundPropagationRule.java b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/impl/rule/BoundPropagationRule.java
index 5f69b7a2..f91882be 100644
--- a/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/impl/rule/BoundPropagationRule.java
+++ b/subprojects/store-dse/src/main/java/tools/refinery/store/dse/propagation/impl/rule/BoundPropagationRule.java
@@ -5,6 +5,7 @@
  */
 package tools.refinery.store.dse.propagation.impl.rule;
 
+import tools.refinery.store.dse.propagation.PropagationRejectedResult;
 import tools.refinery.store.dse.propagation.PropagationResult;
 import tools.refinery.store.dse.transition.Rule;
 import tools.refinery.store.dse.transition.actions.BoundAction;
@@ -54,7 +55,7 @@ class BoundPropagationRule {
 			var tuple = cursor.getKey();
 			var result = action.fire(tuple);
 			if (!result) {
-				return PropagationResult.REJECTED;
+				return new PropagationRejectedResult(rule, "Propagation rule '%s' failed.".formatted(rule.getName()));
 			}
 			firedActivations.add(tuple);
 		}
-- 
cgit v1.2.3-54-g00ecf