[Placement Group] Move PlacementGroup public method to interface. (#13629)

java/api/src/main/java/io/ray/api/placementgroup/PlacementGroup.java

@@ -1,9 +1,57 @@
 package io.ray.api.placementgroup;
 
+import io.ray.api.id.PlacementGroupId;
+import java.util.List;
+import java.util.Map;
+
 /**
  * A placement group is used to place interdependent actors according to a specific strategy {@link
  * PlacementStrategy}. When a placement group is created, the corresponding actor slots and
  * resources are preallocated. A placement group consists of one or more bundles plus a specific
  * placement strategy.
  */
-public interface PlacementGroup {}
+public interface PlacementGroup {
+
+  /**
+   * Get the id of current placement group.
+   *
+   * @return Id of current placement group.
+   */
+  PlacementGroupId getId();
+
+  /**
+   * Get the name of current placement group.
+   *
+   * @return Name of current placement group.
+   */
+  String getName();
+
+  /**
+   * Get all bundles which key is resource name and value is resource value.
+   *
+   * @return All bundles of current placement group.
+   */
+  List<Map<String, Double>> getBundles();
+
+  /**
+   * Get the strategy of current placement group.
+   *
+   * @return Strategy of current placement group.
+   */
+  PlacementStrategy getStrategy();
+
+  /**
+   * Get the state of current placement group.
+   *
+   * @return Creation state of current placement group.
+   */
+  PlacementGroupState getState();
+
+  /**
+   * Wait for the placement group to be ready within the specified time.
+   *
+   * @param timeoutSeconds Timeout in seconds.
+   * @return True if the placement group is created. False otherwise.
+   */
+  boolean wait(int timeoutSeconds);
+}