*** old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.debug/src/org/graalvm/compiler/debug/DebugDumpHandler.java	Fri Jul  7 09:29:53 2017
--- new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.debug/src/org/graalvm/compiler/debug/DebugDumpHandler.java	Fri Jul  7 09:29:52 2017

*** 22,46 ****
--- 22,57 ----
   */
  package org.graalvm.compiler.debug;
  
  import java.io.Closeable;
  
  public interface DebugDumpHandler extends Closeable {
  
      void dump(Object object, String format, Object... arguments);
+ /**
+  * Interface implemented by classes that provide an external visualization of selected object types
+  * such as compiler graphs and nodes. The format and client required to consume the visualizations
+  * is determined by the implementation. For example, a dumper may convert a compiler node to a human
+  * readable string and print it to the console. A more sophisticated dumper may serialize a compiler
+  * graph and send it over the network to a tool (e.g., https://github.com/graalvm/visualizer) that
+  * can display graphs.
+  */
+ public interface DebugDumpHandler extends Closeable, DebugHandler {
  
      /**
       * Add arbitrary capability for use by the handler.
+      * If the type of {@code object} is supported by this dumper, then a representation of
+      * {@code object} is sent to some consumer in a format determined by this object.
       *
!      * @param capability
!      * @param debug the debug context requesting the dump
+      * @param object the object to be dumped
+      * @param format a format string specifying a title that describes the context of the dump
+      *            (e.g., the compiler phase in which request is made)
+      * @param arguments arguments referenced by the format specifiers in {@code format}
       */
      default void addCapability(Object capability) {
      }
+     void dump(DebugContext debug, Object object, String format, Object... arguments);
  
      /**
       * Flushes and releases resources managed by this dump handler. A subsequent call to
!      * {@link #dump(java.lang.Object, java.lang.String, java.lang.Object...)} will create and open
-      * new resources. That is, this method can be used to reset the handler.
!      * {@link #dump} will create and open new resources. That is, this method can be used to reset
!      * the handler.
       */
      @Override
      void close();
+     default void close() {
+     }
  }