1 files changed, 42 insertions, 0 deletions

diff --git a/subprojects/logic/src/main/java/tools/refinery/logic/term/truthvalue/TruthValueDomain.java b/subprojects/logic/src/main/java/tools/refinery/logic/term/truthvalue/TruthValueDomain.java
new file mode 100644
index 00000000..de8a89be
--- /dev/null
+++ b/subprojects/logic/src/main/java/tools/refinery/logic/term/truthvalue/TruthValueDomain.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.logic.term.truthvalue;
+
+import tools.refinery.logic.AbstractDomain;
+
+// Singleton pattern, because there is only one domain for truth values.
+@SuppressWarnings("squid:S6548")
+public final class TruthValueDomain implements AbstractDomain<TruthValue, Boolean> {
+        public static final TruthValueDomain INSTANCE = new TruthValueDomain();
+
+        private TruthValueDomain() {
+        }
+
+        @Override
+        public Class<TruthValue> abstractType() {
+                return TruthValue.class;
+        }
+
+        @Override
+        public Class<Boolean> concreteType() {
+                return Boolean.class;
+        }
+
+        @Override
+        public TruthValue unknown() {
+                return TruthValue.UNKNOWN;
+        }
+
+        @Override
+        public TruthValue error() {
+                return TruthValue.ERROR;
+        }
+
+        @Override
+        public TruthValue toAbstract(Boolean concreteValue) {
+                return TruthValue.toTruthValue(concreteValue);
+        }
+}