mojo: generate Proxies and Stubs for java bindings.

mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java

Index: mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java
diff --git a/mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java b/mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java
index 9ec2cb248e0bb8cc5e697a29cdec93f84398bbf8..22af8518735c4df2d635a3bd3c2669f3af86f007 100644
--- a/mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java
+++ b/mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java
@@ -7,6 +7,8 @@ package org.chromium.mojo.bindings;
 import org.chromium.mojo.bindings.Struct.DataHeader;
 import org.chromium.mojo.system.Core;
 import org.chromium.mojo.system.Handle;
+import org.chromium.mojo.system.MessagePipeHandle;
+import org.chromium.mojo.system.Pair;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -139,7 +141,6 @@ public class Encoder {
         Encoder result = new Encoder(mEncoderState);
         result.encode(dataHeader);
         return result;
-
     }
 
     /**
@@ -243,25 +244,42 @@ public class Encoder {
     /**
      * Encode an {@link Interface}.
      */
-    public <T extends Interface> void encode(T v, int offset, Object builder) {
+    public <T extends Interface> void encode(T v, int offset, Interface.Builder<T, ?> builder) {
+        if (v == null) {
+            encode(-1, offset);
+            return;
+        }
         if (mEncoderState.core == null) {
             throw new UnsupportedOperationException(
                     "The encoder has been created without a Core. It can't encode an interface.");
         }
-        // TODO(qsr): To be implemented when interfaces proxy and stubs are implemented.
-        throw new UnsupportedOperationException("Unimplemented operation");
+        // If the instance is a proxy, pass the proxy's handle instead of creating a new stub.
+        if (v instanceof Interface.AbstractProxy) {

[rmcilroy, 2014/08/21 14:43:52]

Would it work to have a getHandleOwnerMessageReciever method on Interface and
using that if it returns a non-null value?  I realize you want to keep the
"Interface" interface clean to avoid name clash with mojom interface members,
but don't you already have this issue where  mojo functions might overlap with
setErrorHandler() and any functions in Proxy (e.g. getMessageReceiver()), etc?

[qsr, 2014/08/22 08:11:18]

 The other issue is that Interface will be implemented when implementing a
service, and I don't want to force to implement methods that returns null and do
not give any value. And we would still need a instanceof n Proxy to implement
this because not all MessageReceiver are HandleOwner.

[rmcilroy, 2014/08/26 10:18:23]

Yeah, makes sense (re: not wanting the service to have to implement this
method).

+            Interface.AbstractProxy proxy = (Interface.AbstractProxy) v;
+            if (proxy.getMessageReceiver() instanceof HandleOwner) {
+                encode(((HandleOwner<?>) proxy.getMessageReceiver()).passHandle(), offset);
+                return;
+            }
+        }
+        Pair<MessagePipeHandle, MessagePipeHandle> handles =
+                mEncoderState.core.createMessagePipe(null);
+        builder.bind(handles.first, v);
+        encode(handles.second, offset);
     }
 
     /**
      * Encode an {@link InterfaceRequest}.
      */
-    public <T extends Interface> void encode(InterfaceRequest<T> v, int offset) {
+    public <P extends Interface.Proxy> void encode(InterfaceRequest<P> v, int offset) {
+        if (v == null) {
+            encode(-1, offset);
+            return;
+        }
         if (mEncoderState.core == null) {
             throw new UnsupportedOperationException(
                     "The encoder has been created without a Core. It can't encode an interface.");
         }
-        // TODO(qsr): To be implemented when interfaces proxy and stubs are implemented.
-        throw new UnsupportedOperationException("Unimplemented operation");
+        encode(v.passHandle(), offset);
     }
 
     /**
@@ -347,7 +365,7 @@ public class Encoder {
     }
 
     /**
-     * Encodes an array of doubles.
+     * Encodes an array of doubles
      */
     public void encode(double[] v, int offset) {
         if (v == null) {
@@ -374,7 +392,8 @@ public class Encoder {
     /**
      * Encodes an array of {@link Interface}.
      */
-    public <T extends Interface> void encode(T[] v, int offset, Object builder) {
+    public <T extends Interface> void encode(T[] v, int offset,
+            Interface.Builder<T, ?> builder) {
         if (v == null) {
             encodeNullPointer(offset);
             return;
@@ -387,9 +406,9 @@ public class Encoder {
     }
 
     /**
-     * Encodes an array of {@link Interface}.
+     * Encodes an array of {@link InterfaceRequest}.
      */
-    public <T extends Interface> void encode(InterfaceRequest<T>[] v, int offset) {
+    public <P extends Interface.Proxy> void encode(InterfaceRequest<P>[] v, int offset) {
         if (v == null) {
             encodeNullPointer(offset);
             return;