chore: Ensure LoopAgent uses the same builder heirarchy as other agents

PiperOrigin-RevId: 843702422

Author: google-genai-bot

core/src/main/java/com/google/adk/agents/LoopAgent.java

@@ -17,7 +17,6 @@
 package com.google.adk.agents;
 
 import com.google.adk.events.Event;
-import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import io.reactivex.rxjava3.core.Flowable;
 import java.util.List;
@@ -56,37 +55,8 @@ private LoopAgent(
   }
 
   /** Builder for {@link LoopAgent}. */
-  public static class Builder {
-    private String name;
-    private String description;
-    private List<? extends BaseAgent> subAgents;
+  public static class Builder extends BaseAgent.Builder<Builder> {
     private Optional<Integer> maxIterations = Optional.empty();
-    private ImmutableList<Callbacks.BeforeAgentCallback> beforeAgentCallback;
-    private ImmutableList<Callbacks.AfterAgentCallback> afterAgentCallback;
-
-    @CanIgnoreReturnValue
-    public Builder name(String name) {
-      this.name = name;
-      return this;
-    }
-
-    @CanIgnoreReturnValue
-    public Builder description(String description) {
-      this.description = description;
-      return this;
-    }
-
-    @CanIgnoreReturnValue
-    public Builder subAgents(List<? extends BaseAgent> subAgents) {
-      this.subAgents = subAgents;
-      return this;
-    }
-
-    @CanIgnoreReturnValue
-    public Builder subAgents(BaseAgent... subAgents) {
-      this.subAgents = ImmutableList.copyOf(subAgents);
-      return this;
-    }
 
     @CanIgnoreReturnValue
     public Builder maxIterations(int maxIterations) {
@@ -100,31 +70,7 @@ public Builder maxIterations(Optional<Integer> maxIterations) {
       return this;
     }
 
-    @CanIgnoreReturnValue
-    public Builder beforeAgentCallback(Callbacks.BeforeAgentCallback beforeAgentCallback) {
-      this.beforeAgentCallback = ImmutableList.of(beforeAgentCallback);
-      return this;
-    }
-
-    @CanIgnoreReturnValue
-    public Builder beforeAgentCallback(
-        List<Callbacks.BeforeAgentCallbackBase> beforeAgentCallback) {
-      this.beforeAgentCallback = CallbackUtil.getBeforeAgentCallbacks(beforeAgentCallback);
-      return this;
-    }
-
-    @CanIgnoreReturnValue
-    public Builder afterAgentCallback(Callbacks.AfterAgentCallback afterAgentCallback) {
-      this.afterAgentCallback = ImmutableList.of(afterAgentCallback);
-      return this;
-    }
-
-    @CanIgnoreReturnValue
-    public Builder afterAgentCallback(List<Callbacks.AfterAgentCallbackBase> afterAgentCallback) {
-      this.afterAgentCallback = CallbackUtil.getAfterAgentCallbacks(afterAgentCallback);
-      return this;
-    }
-
+    @Override
     public LoopAgent build() {
       // TODO(b/410859954): Add validation for required fields like name.
       return new LoopAgent(