- Implemented ResolvedValue class for resolving value at given path

sacOO7 · sacOO7 · commit 54ae53f0f1ea · 2026-06-17T17:34:09.000+05:30
- Marked PathObject#getValue as nullable when value doesn't exist at given path
diff --git a/lib/src/main/java/io/ably/lib/object/ValueType.java b/lib/src/main/java/io/ably/lib/object/ValueType.java
@@ -23,6 +23,6 @@ public enum ValueType {
     LIVE_MAP,
     /** Corresponds to a {@code LiveCounter} object. Spec: RTTS2a8 */
     LIVE_COUNTER,
-    /** Returned when path resolution fails or the resolved value has none of the known types; never produced by an {@code Instance} in normal operation. Spec: RTTS2a9 */
+    /** Returned by {@code PathObject#getType()} only when a value is present but matches none of the known types. Never produced by an {@code Instance} in normal operation. Spec: RTTS2a9 */
     UNKNOWN,
 }
diff --git a/lib/src/main/java/io/ably/lib/object/path/PathObject.java b/lib/src/main/java/io/ably/lib/object/path/PathObject.java
@@ -43,17 +43,22 @@
 public interface PathObject {
 
     /**
-     * Returns the {@link ValueType} of the value resolved at this path currently.
-     * Use this instead of dedicated {@code isLiveMap}/{@code isLiveCounter}/etc. checks.
+     * Returns the {@link ValueType} of the value currently resolved at this path, or
+     * {@code null} when the path does not resolve to any value. Use this instead of
+     * dedicated {@code isLiveMap}/{@code isLiveCounter}/etc. checks.
      *
-     * <p>Returns {@link ValueType#UNKNOWN} when the path does not resolve or the
-     * resolved value falls into none of the known categories.
+     * <p>A {@code null} result means there is no value at this path - nothing is stored
+     * there (e.g. an absent or removed map entry). This is deliberately distinct from
+     * {@link ValueType#UNKNOWN}, which is returned only when a value <em>is</em> present
+     * but its type matches none of the known categories. In other words: {@code null}
+     * means "no value", {@code UNKNOWN} means "a value of an unrecognized type".
      *
      * <p>Spec: RTTS4b
      *
-     * @return the resolved value type at this path
+     * @return the resolved value type at this path, or {@code null} if the path does
+     *         not resolve to a value
      */
-    @NotNull ValueType getType();
+    @Nullable ValueType getType();
 
     /**
      * Returns a dot-delimited string representation of the stored path segments.
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/DefaultPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/DefaultPathObject.kt
@@ -22,6 +22,8 @@ import io.ably.lib.`object`.path.types.LiveCounterPathObject
 import io.ably.lib.`object`.path.types.LiveMapPathObject
 import io.ably.lib.`object`.path.types.NumberPathObject
 import io.ably.lib.`object`.path.types.StringPathObject
+import io.ably.lib.`object`.value.ResolvedValue
+import io.ably.lib.`object`.value.valueType
 
 /**
  * Default implementation of [PathObject], the untyped node in the path-addressed view of
@@ -35,33 +37,34 @@ import io.ably.lib.`object`.path.types.StringPathObject
  */
 internal open class DefaultPathObject(
   internal val channelObject: DefaultRealtimeObject,
+  internal val path: String
 ) : PathObject {
 
-  override fun path(): String = TODO("Not yet implemented")
+  override fun path(): String = path
 
-  override fun getType(): ValueType = TODO("Not yet implemented")
+  override fun getType(): ValueType? = resolveValueAtPath(path)?.valueType()
 
   override fun instance(): Instance? = TODO("Not yet implemented")
 
   override fun compactJson(): JsonElement? = TODO("Not yet implemented")
 
-  override fun exists(): Boolean = TODO("Not yet implemented")
+  override fun exists(): Boolean = resolveValueAtPath(path) != null
 
-  override fun asLiveMap(): LiveMapPathObject = DefaultLiveMapPathObject(channelObject)
+  override fun asLiveMap(): LiveMapPathObject = DefaultLiveMapPathObject(channelObject, path)
 
-  override fun asLiveCounter(): LiveCounterPathObject = DefaultLiveCounterPathObject(channelObject)
+  override fun asLiveCounter(): LiveCounterPathObject = DefaultLiveCounterPathObject(channelObject, path)
 
-  override fun asNumber(): NumberPathObject = DefaultNumberPathObject(channelObject)
+  override fun asNumber(): NumberPathObject = DefaultNumberPathObject(channelObject, path)
 
-  override fun asString(): StringPathObject = DefaultStringPathObject(channelObject)
+  override fun asString(): StringPathObject = DefaultStringPathObject(channelObject, path)
 
-  override fun asBoolean(): BooleanPathObject = DefaultBooleanPathObject(channelObject)
+  override fun asBoolean(): BooleanPathObject = DefaultBooleanPathObject(channelObject, path)
 
-  override fun asBinary(): BinaryPathObject = DefaultBinaryPathObject(channelObject)
+  override fun asBinary(): BinaryPathObject = DefaultBinaryPathObject(channelObject, path)
 
-  override fun asJsonObject(): JsonObjectPathObject = DefaultJsonObjectPathObject(channelObject)
+  override fun asJsonObject(): JsonObjectPathObject = DefaultJsonObjectPathObject(channelObject, path)
 
-  override fun asJsonArray(): JsonArrayPathObject = DefaultJsonArrayPathObject(channelObject)
+  override fun asJsonArray(): JsonArrayPathObject = DefaultJsonArrayPathObject(channelObject, path)
 
   override fun subscribe(listener: PathObjectListener): Subscription = subscribe(listener, null)
 
@@ -71,4 +74,9 @@ internal open class DefaultPathObject(
       // TODO - remove PathObjectListener from list
     }
   }
+
+  protected fun resolveValueAtPath(path: String): ResolvedValue? {
+    // TODO - resolve the path against the live objects graph and return the value at that position
+    return null
+  }
 }
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultBinaryPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultBinaryPathObject.kt
@@ -11,7 +11,8 @@ import io.ably.lib.`object`.path.DefaultPathObject
  */
 internal class DefaultBinaryPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), BinaryPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), BinaryPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): ByteArray? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultBooleanPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultBooleanPathObject.kt
@@ -11,7 +11,8 @@ import io.ably.lib.`object`.path.DefaultPathObject
  */
 internal class DefaultBooleanPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), BooleanPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), BooleanPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): Boolean? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultJsonArrayPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultJsonArrayPathObject.kt
@@ -12,7 +12,8 @@ import io.ably.lib.`object`.path.DefaultPathObject
  */
 internal class DefaultJsonArrayPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), JsonArrayPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), JsonArrayPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): JsonArray? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultJsonObjectPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultJsonObjectPathObject.kt
@@ -12,7 +12,8 @@ import io.ably.lib.`object`.path.DefaultPathObject
  */
 internal class DefaultJsonObjectPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), JsonObjectPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), JsonObjectPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): JsonObject? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultLiveCounterPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultLiveCounterPathObject.kt
@@ -14,7 +14,8 @@ import java.util.concurrent.CompletableFuture
  */
 internal class DefaultLiveCounterPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), LiveCounterPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), LiveCounterPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): Double? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultLiveMapPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultLiveMapPathObject.kt
@@ -14,7 +14,8 @@ import java.util.concurrent.CompletableFuture
  */
 internal class DefaultLiveMapPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), LiveMapPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), LiveMapPathObject {
 
   override fun get(key: String): PathObject = TODO("Not yet implemented")
 
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultNumberPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultNumberPathObject.kt
@@ -11,7 +11,8 @@ import io.ably.lib.`object`.path.DefaultPathObject
  */
 internal class DefaultNumberPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), NumberPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), NumberPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): Number? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultStringPathObject.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/path/types/DefaultStringPathObject.kt
@@ -11,7 +11,8 @@ import io.ably.lib.`object`.path.DefaultPathObject
  */
 internal class DefaultStringPathObject(
   channelObject: DefaultRealtimeObject,
-) : DefaultPathObject(channelObject), StringPathObject {
+  path: String,
+) : DefaultPathObject(channelObject, path), StringPathObject {
 
   @Suppress("RedundantNullableReturnType")
   override fun value(): String? = TODO("Not yet implemented")
diff --git a/liveobjects/src/main/kotlin/io/ably/lib/object/value/ResolvedValue.kt b/liveobjects/src/main/kotlin/io/ably/lib/object/value/ResolvedValue.kt
@@ -0,0 +1,39 @@
+package io.ably.lib.`object`.value
+
+import io.ably.lib.`object`.ValueType
+import io.ably.lib.`object`.message.WireObjectData
+
+/**
+ * The result of resolving a path segment / map entry against the objects
+ * graph: either a node view of a live object, or a primitive leaf carried as
+ * wire ObjectData.
+ */
+internal sealed interface ResolvedValue {
+  data class MapRef(val map: LiveMap) : ResolvedValue // TODO: LiveMap will be replaced by InternalLiveMap
+  data class CounterRef(val counter: LiveCounter) : ResolvedValue // TODO: LiveCounter will be replaced by InternalLiveCounter
+  data class Leaf(val data: WireObjectData) : ResolvedValue
+}
+
+/**
+ * Maps a resolved value to the public ValueType enum.
+ *
+ * Only ever invoked on a value that resolved to something - absence at a path is
+ * represented by a `null` [ResolvedValue] and surfaced as a `null` type by the
+ * caller, never as [ValueType.UNKNOWN]. UNKNOWN is reserved for a value that is
+ * present but matches none of the known categories.
+ *
+ * Spec: RTTS2a, RTTS4b3
+ */
+internal fun ResolvedValue.valueType(): ValueType = when (this) {
+  is ResolvedValue.MapRef -> ValueType.LIVE_MAP
+  is ResolvedValue.CounterRef -> ValueType.LIVE_COUNTER
+  is ResolvedValue.Leaf -> when {
+    data.string != null -> ValueType.STRING
+    data.number != null -> ValueType.NUMBER
+    data.boolean != null -> ValueType.BOOLEAN
+    data.bytes != null -> ValueType.BINARY
+    data.json?.isJsonObject == true -> ValueType.JSON_OBJECT
+    data.json?.isJsonArray == true -> ValueType.JSON_ARRAY
+    else -> ValueType.UNKNOWN
+  }
+}

Original file line number	Diff line number	Diff line change
`@@ -23,6 +23,6 @@ public enum ValueType {`
`23`	`23`	`LIVE_MAP,`
`24`	`24`	`/** Corresponds to a {@code LiveCounter} object. Spec: RTTS2a8 */`
`25`	`25`	`LIVE_COUNTER,`
`26`		`- /** Returned when path resolution fails or the resolved value has none of the known types; never produced by an {@code Instance} in normal operation. Spec: RTTS2a9 */`
	`26`	`+ /** Returned by {@code PathObject#getType()} only when a value is present but matches none of the known types. Never produced by an {@code Instance} in normal operation. Spec: RTTS2a9 */`
`27`	`27`	`UNKNOWN,`
`28`	`28`	`}`