BodyInterface: add accessors for user data

src/main/java/com/github/stephengold/joltjni/BodyInterface.java

@@ -551,6 +551,20 @@ public PhysicsSystem getSystem() {
         return result;
     }
 
+    /**
+     * Return the user data of the specified body.
+     *
+     * @param bodyId the ID of the body (not null, unaffected)
+     * @return the value
+     */
+    public long getUserData(ConstBodyId bodyId) {
+        long bodyInterfaceVa = va();
+        long bodyIdVa = bodyId.targetVa();
+        long result = getUserData(bodyInterfaceVa, bodyIdVa);
+
+        return result;
+    }
+
     /**
      * Test whether the specified body is active.
      *
@@ -818,6 +832,18 @@ public void setShape(ConstBodyId bodyId, ConstShape shape,
         setShape(bodyInterfaceVa, bodyIdVa, shapeVa, updateMassProperties,
                 ordinal);
     }
+
+    /**
+     * Alter the user data of the specified body.
+     *
+     * @param bodyId the ID of the body to modify (not null, unaffected)
+     * @param value the desired value
+     */
+    public void setUserData(ConstBodyId bodyId, long value) {
+        long bodyInterfaceVa = va();
+        long bodyIdVa = bodyId.targetVa();
+        setUserData(bodyInterfaceVa, bodyIdVa, value);
+    }
     // *************************************************************************
     // native private methods
 
@@ -934,6 +960,7 @@ native private static float getRotationZ(
 
     native private static long getShape(long bodyInterfaceVa, long bodyIdVa);
 
+    native private static long getUserData(long bodyInterfaceVa, long bodyIdVa);
 
     native private static boolean isActive(long bodyInterfaceVa, long bodyIdVa);
 
@@ -986,4 +1013,7 @@ native private static void setRestitution(
 
     native private static void setShape(long bodyInterfaceVa, long bodyIdVa,
             long shapeVa, boolean updateMassProperties, int ordinal);
+
+    native private static void setUserData(
+            long bodyInterfaceVa, long bodyIdVa, long value);
 }

src/main/native/glue/bo/BodyInterface.cpp

@@ -572,6 +572,20 @@ JNIEXPORT jlong JNICALL Java_com_github_stephengold_joltjni_BodyInterface_getSha
     return reinterpret_cast<jlong> (pResult);
 }
 
+/*
+ * Class:     com_github_stephengold_joltjni_BodyInterface
+ * Method:    getUserData
+ * Signature: (JJ)J
+ */
+JNIEXPORT jlong JNICALL Java_com_github_stephengold_joltjni_BodyInterface_getUserData
+  (JNIEnv *, jclass, jlong bodyInterfaceVa, jlong bodyIdVa) {
+    const BodyInterface * const pInterface
+            = reinterpret_cast<BodyInterface *> (bodyInterfaceVa);
+    const BodyID * const pBodyId = reinterpret_cast<BodyID *> (bodyIdVa);
+    const uint64 result = pInterface->GetUserData(*pBodyId);
+    return result;
+}
+
 /*
  * Class:     com_github_stephengold_joltjni_BodyInterface
  * Method:    isActive
@@ -825,4 +839,17 @@ JNIEXPORT void JNICALL Java_com_github_stephengold_joltjni_BodyInterface_setShap
     const Shape * const pShape = reinterpret_cast<Shape *> (shapeVa);
     const EActivation activation = (EActivation) ordinal;
     pInterface->SetShape(*pBodyId, pShape, updateMassProperties, activation);
+}
+
+/*
+ * Class:     com_github_stephengold_joltjni_BodyInterface
+ * Method:    setUserData
+ * Signature: (JJJ)V
+ */
+JNIEXPORT void JNICALL Java_com_github_stephengold_joltjni_BodyInterface_setUserData
+  (JNIEnv *, jclass, jlong bodyInterfaceVa, jlong bodyIdVa, jlong value) {
+    BodyInterface * const pInterface
+            = reinterpret_cast<BodyInterface *> (bodyInterfaceVa);
+    const BodyID * const pBodyId = reinterpret_cast<BodyID *> (bodyIdVa);
+    pInterface->SetUserData(*pBodyId, value);
 }