add the ConstBodyId interface

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

@@ -243,10 +243,10 @@ public float getFriction() {
      *
      * @return the value
      */
-    public BodyId getId() {
+    public ConstBodyId getId() {
         long bodyVa = va();
         long bodyIdVa = getId(bodyVa);
-        BodyId result = new BodyId(bodyIdVa);
+        ConstBodyId result = new BodyId(bodyIdVa);
 
         return result;
     }

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

@@ -26,7 +26,7 @@ of this software and associated documentation files (the "Software"), to deal
  *
  * @author Stephen Gold [email protected]
  */
-public class BodyId extends JoltPhysicsObject {
+public class BodyId extends JoltPhysicsObject implements ConstBodyId {
     // *************************************************************************
     // constructors
 
@@ -39,14 +39,15 @@ public class BodyId extends JoltPhysicsObject {
         super(idVa);
     }
     // *************************************************************************
-    // new methods exposed
+    // ConstBodyId methods
 
     /**
      * Return the body's index in the body array. The current instance is
      * unaffected.
      *
      * @return the index (≥0)
      */
+    @Override
     public int getIndex() {
         long idVa = va();
         int result = getIndex(idVa);
@@ -59,6 +60,7 @@ public int getIndex() {
      *
      * @return the sequence number (≥0)
      */
+    @Override
     public int getSequenceNumber() {
         long idVa = va();
         int result = getSequenceNumber(idVa);
@@ -71,6 +73,7 @@ public int getSequenceNumber() {
      *
      * @return true if invalid, false if valid
      */
+    @Override
     public boolean isInvalid() {
         long idVa = va();
         boolean result = isInvalid(idVa);

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

@@ -42,7 +42,7 @@ public class BodyInterface extends NonCopyable {
      *
      * @param bodyId the ID of the body to activate (not null)
      */
-    public void activateBody(BodyId bodyId) {
+    public void activateBody(ConstBodyId bodyId) {
         long bodyInterfaceVa = va();
         long bodyIdVa = bodyId.va();
         activateBody(bodyInterfaceVa, bodyIdVa);
@@ -54,7 +54,7 @@ public void activateBody(BodyId bodyId) {
      * @param bodyId the ID of the body to add (not null)
      * @param activation whether to activate the body (not null)
      */
-    public void addBody(BodyId bodyId, EActivation activation) {
+    public void addBody(ConstBodyId bodyId, EActivation activation) {
         long bodyInterfaceVa = va();
         long bodyIdVa = bodyId.va();
         int activationOrdinal = activation.ordinal();
@@ -68,10 +68,10 @@ public void addBody(BodyId bodyId, EActivation activation) {
      * @param activationMode whether to activate the body (not null)
      * @return the ID of the created body, or an invalid ID when out of bodies
      */
-    public BodyId createAndAddBody(
+    public ConstBodyId createAndAddBody(
             BodyCreationSettings settings, EActivation activationMode) {
         Body body = createBody(settings);
-        BodyId result = body.getId();
+        ConstBodyId result = body.getId();
         addBody(result, activationMode);
 
         return result;
@@ -100,7 +100,7 @@ public Body createBody(BodyCreationSettings settings) {
      *
      * @param bodyId the ID of the body to destroy (not null)
      */
-    public void destroyBody(BodyId bodyId) {
+    public void destroyBody(ConstBodyId bodyId) {
         long bodyInterfaceVa = va();
         long bodyIdVa = bodyId.va();
         destroyBody(bodyInterfaceVa, bodyIdVa);
@@ -112,7 +112,7 @@ public void destroyBody(BodyId bodyId) {
      * @param bodyId the ID of the body to locate (not null)
      * @return a new vector
      */
-    public RVec3 getCenterOfMassPosition(BodyId bodyId) {
+    public RVec3 getCenterOfMassPosition(ConstBodyId bodyId) {
         long bodyInterfaceVa = va();
         long bodyIdVa = bodyId.va();
         double xx = getCenterOfMassPositionX(bodyInterfaceVa, bodyIdVa);
@@ -129,7 +129,7 @@ public RVec3 getCenterOfMassPosition(BodyId bodyId) {
      * @param bodyId the ID of the body (not null)
      * @return a new vector
      */
-    public Vec3 getLinearVelocity(BodyId bodyId) {
+    public Vec3 getLinearVelocity(ConstBodyId bodyId) {
         long bodyInterfaceVa = va();
         long bodyIdVa = bodyId.va();
         float x = getLinearVelocityX(bodyInterfaceVa, bodyIdVa);
@@ -145,7 +145,7 @@ public Vec3 getLinearVelocity(BodyId bodyId) {
      *
      * @param bodyId the ID of the body to remove (not null)
      */
-    public void removeBody(BodyId bodyId) {
+    public void removeBody(ConstBodyId bodyId) {
         long bodyIdVa = bodyId.va();
         removeBody(va(), bodyIdVa);
     }
@@ -156,7 +156,7 @@ public void removeBody(BodyId bodyId) {
      * @param bodyId the ID of the body to test (not null)
      * @return true if active, otherwise false
      */
-    public boolean isActive(BodyId bodyId) {
+    public boolean isActive(ConstBodyId bodyId) {
         long bodyIdVa = bodyId.va();
         boolean result = isActive(va(), bodyIdVa);
         return result;
@@ -168,7 +168,7 @@ public boolean isActive(BodyId bodyId) {
      * @param bodyId the ID of the body to test (not null)
      * @param omega the desired rates (not null, unaffected)
      */
-    public void setAngularVelocity(BodyId bodyId, Vec3Arg omega) {
+    public void setAngularVelocity(ConstBodyId bodyId, Vec3Arg omega) {
         long bodyInterfaceVa = va();
         long bodyIdVa = bodyId.va();
         setAngularVelocity(bodyInterfaceVa, bodyIdVa,
@@ -181,7 +181,7 @@ public void setAngularVelocity(BodyId bodyId, Vec3Arg omega) {
      * @param bodyId the ID of the body to test (not null)
      * @param velocity the desired velocity (not null, unaffected)
      */
-    public void setLinearVelocity(BodyId bodyId, Vec3Arg velocity) {
+    public void setLinearVelocity(ConstBodyId bodyId, Vec3Arg velocity) {
         long bodyIdVa = bodyId.va();
         setLinearVelocity(va(), bodyIdVa,
                 velocity.getX(), velocity.getY(), velocity.getZ());

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

@@ -0,0 +1,54 @@
+/*
+Copyright (c) 2024 Stephen Gold
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+package com.github.stephengold.joltjni;
+
+/**
+ * An immutable {@code BodyId}.
+ *
+ * @author Stephen Gold [email protected]
+ */
+public interface ConstBodyId extends ConstJoltPhysicsObject {
+    // *************************************************************************
+    // new methods exposed
+
+    /**
+     * Return the body's index in the body array. The current instance is
+     * unaffected.
+     *
+     * @return the index (≥0)
+     */
+    int getIndex();
+
+    /**
+     * Return the body's sequence number. The current instance is unaffected.
+     *
+     * @return the sequence number (≥0)
+     */
+    int getSequenceNumber();
+
+    /**
+     * Test whether the ID is valid. The current instance is unaffected.
+     *
+     * @return true if invalid, false if valid
+     */
+    boolean isInvalid();
+}

src/test/java/testjoltjni/app/HelloWorld.java

@@ -141,7 +141,7 @@ public static void main(String[] argv)
 	// Now create a dynamic body to bounce on the floor
 	// Note that this uses the shorthand version of creating and adding a body to the world
 	BodyCreationSettings sphere_settings = new BodyCreationSettings(new SphereShape(0.5f), new RVec3(0f, 2f, 0f), new Quat(), EMotionType.Dynamic, OBJ_LAYER_MOVING);
-	BodyId sphere_id = body_interface.createAndAddBody(sphere_settings, EActivation.Activate);
+	ConstBodyId sphere_id = body_interface.createAndAddBody(sphere_settings, EActivation.Activate);
 
 	// Now you can interact with the dynamic body, in this case we're going to give it a velocity.
 	// (note that if we had used CreateBody then we could have set the velocity straight on the body before adding it to the physics system)

src/test/java/testjoltjni/junit/Test001.java

@@ -23,9 +23,9 @@ of this software and associated documentation files (the "Software"), to deal
 
 import com.github.stephengold.joltjni.Body;
 import com.github.stephengold.joltjni.BodyCreationSettings;
-import com.github.stephengold.joltjni.BodyId;
 import com.github.stephengold.joltjni.BodyInterface;
 import com.github.stephengold.joltjni.BoxShapeSettings;
+import com.github.stephengold.joltjni.ConstBodyId;
 import com.github.stephengold.joltjni.EActivation;
 import com.github.stephengold.joltjni.EMotionType;
 import com.github.stephengold.joltjni.EPhysicsUpdateError;
@@ -105,7 +105,7 @@ public void test001() {
                 = new BodyCreationSettings(floorShapeSettings, floorLocation,
                         orientation, EMotionType.Static, objLayerNonMoving);
         Body floor = bodyInterface.createBody(floorBodySettings);
-        BodyId floorId = floor.getId();
+        ConstBodyId floorId = floor.getId();
         bodyInterface.addBody(floorId, EActivation.DontActivate);
 
         Shape ballShape = new SphereShape(0.5f);
@@ -116,7 +116,7 @@ public void test001() {
         BodyCreationSettings ballSettings = new BodyCreationSettings(
                 ballShape, ballLocation, orientation,
                 EMotionType.Dynamic, objLayerMoving);
-        BodyId ballId = bodyInterface.createAndAddBody(
+        ConstBodyId ballId = bodyInterface.createAndAddBody(
                 ballSettings, EActivation.Activate);
         Vec3 ballVelocity = new Vec3(0f, -5f, 0f);
         bodyInterface.setLinearVelocity(ballId, ballVelocity);