mojo: Fix java generator

mojo/public/tools/bindings/generators/java_templates/interface_definition.tmpl

 {% from "constant_definition.tmpl" import constant_def %}
 {% from "enum_definition.tmpl" import enum_def %}
 {% from "struct_definition.tmpl" import struct_def %}
 
 {%- macro declare_params(parameters, boxed=false) %}
 {%-   for param in parameters -%}
 {{param.kind|java_type(boxed)}} {{param|name}}
 {%- if not loop.last %}, {% endif %}
 {%-   endfor %}
 {%- endmacro %}
 
 {% macro declare_request_params(method) %}
 {{declare_params(method.parameters)}}
 {%-   if method.response_parameters != None -%}
 {%- if method.parameters %}, {% endif %}
 {{method|interface_response_name}} callback
 {%-   endif -%}
 {% endmacro %}
 
 {%- macro declare_callback(method) -%}
 
-interface {{method|interface_response_name}} extends org.chromium.mojo.bindings.Callbacks.Callback{{method.response_parameters|length}}<
+interface {{method|interface_response_name}} extends org.chromium.mojo.bindings.Callbacks.Callback{{method.response_parameters|length}}{% if method.response_parameters %}<
 {%-   for param in method.response_parameters -%}
 {{param.kind|java_type(True)}}
 {%- if not loop.last %}, {% endif %}
 {%-   endfor -%}
-> { }
+>{% endif %} { }
 {%- endmacro -%}
 
 {%- macro run_callback(variable, parameters) -%}
 {%-   if parameters -%}
 {%-     for param in parameters -%}
 {{variable}}.{{param|name}}
 {%-   if not loop.last %}, {% endif %}
 {%-     endfor -%}
 {%-   endif -%}
 {%- endmacro -%}
@@ skipping 60 matching lines @@
       (interface|has_method_without_response and not with_response) %}
 try {
     org.chromium.mojo.bindings.ServiceMessage messageWithHeader =
             message.asServiceMessage();
     org.chromium.mojo.bindings.MessageHeader header = messageWithHeader.getHeader();
     if (!header.validateHeader({{flags(with_response, True)}})) {
         return false;
     }
     switch(header.getType()) {
 {%   for method in interface.methods %}
-{%     if (with_response and method.response_parameters) or
-        (not with_response and not method.response_parameters) %}
+{%     if (with_response and method.response_parameters != None) or
+        (not with_response and method.response_parameters == None) %}
 {%       set request_struct = method|struct_from_method %}
 {%       if with_response %}
 {%         set response_struct = method|response_struct_from_method %}
 {%       endif %}
         case {{method|method_ordinal_name}}: {
 {%       if method.parameters %}
             {{request_struct|name}} data =
                     {{request_struct|name}}.deserialize(messageWithHeader.getPayload());
 {%       else %}
             {{request_struct|name}}.deserialize(messageWithHeader.getPayload());
@@ skipping 25 matching lines @@
     {{enum_def(enum, false)|indent(4)}}
 {% endfor %}
 
     public interface Proxy extends {{interface|name}}, {{super_class(client, False)}}.Proxy{% if client %}<{{client|java_type}}>{% endif %} {
     }
 
     {{manager_class(interface, client)}} MANAGER = {{interface|name}}_Internal.MANAGER;
 {% for method in interface.methods %}
 
     void {{method|name}}({{declare_request_params(method)}});
-{%   if method.response_parameters %}
+{%   if method.response_parameters != None %}
     {{declare_callback(method)|indent(4)}}
 {%   endif %}
 {% endfor %}
 }
 {% endmacro %}
 
 {% macro interface_internal_def(interface, client) %}
 class {{interface|name}}_Internal {
 
     {{manager_def(interface, client)|indent(4)}}
 
 {% for method in interface.methods %}
     private static final int {{method|method_ordinal_name}} = {{method.ordinal}};
 {% endfor %}
 
     static final class Proxy extends {% if client %}org.chromium.mojo.bindings.InterfaceWithClient.AbstractProxy<{{client|java_type}}>{% else %}org.chromium.mojo.bindings.Interface.AbstractProxy{% endif %} implements {{interface|name}}.Proxy {
 
         Proxy(org.chromium.mojo.system.Core core,
               org.chromium.mojo.bindings.MessageReceiverWithResponder messageReceiver) {
             super(core, messageReceiver);
         }
 {% for method in interface.methods %}
 
         @Override
         public void {{method|name}}({{declare_request_params(method)}}) {
 {%   set request_struct = method|struct_from_method %}
-            {{request_struct|name}} message = new {{request_struct|name}}();
+            {{request_struct|name}} _message = new {{request_struct|name}}();
 {%   for param in method.parameters %}
-            message.{{param|name}} = {{param|name}};
+            _message.{{param|name}} = {{param|name}};
 {%   endfor %}
-{%   if method.response_parameters %}
+{%   if method.response_parameters != None %}
             getMessageReceiver().acceptWithResponder(
-                    message.serializeWithHeader(
+                    _message.serializeWithHeader(
                             getCore(),
                             new org.chromium.mojo.bindings.MessageHeader(
                                     {{method|method_ordinal_name}},
                                     {{flags_for_method(method, True)}},
                                     0)),
                     new {{method|response_struct_from_method|name}}ForwardToCallback(callback));
 {%   else %}
             getMessageReceiver().accept(
-                    message.serializeWithHeader(
+                    _message.serializeWithHeader(
                             getCore(),
                             new org.chromium.mojo.bindings.MessageHeader({{method|method_ordinal_name}})));
 {%   endif %}
         }
 {% endfor %}
 
     }
 
     static final class Stub extends org.chromium.mojo.bindings.Interface.Stub<{{interface|name}}> {
 
         Stub(org.chromium.mojo.system.Core core, {{interface|name}} impl) {
             super(core, impl);
         }
 
         @Override
         public boolean accept(org.chromium.mojo.bindings.Message message) {
             {{accept_body(interface, False)|indent(12)}}
         }
 
         @Override
         public boolean acceptWithResponder(org.chromium.mojo.bindings.Message message, org.chromium.mojo.bindings.MessageReceiver receiver) {
             {{accept_body(interface, True)|indent(12)}}
         }
     }
 {% for method in interface.methods %}
 
     {{ struct_def(method|struct_from_method, True)|indent(4) }}
-{%   if method.response_parameters %}
+{%   if method.response_parameters != None %}
 {%   set response_struct = method|response_struct_from_method %}
 
     {{ struct_def(response_struct, True)|indent(4) }}
 
     static class {{response_struct|name}}ForwardToCallback extends org.chromium.mojo.bindings.SideEffectFreeCloseable
             implements org.chromium.mojo.bindings.MessageReceiver {
         private final {{interface|name}}.{{method|interface_response_name}} mCallback;
 
         {{response_struct|name}}ForwardToCallback({{interface|name}}.{{method|interface_response_name}} callback) {
             this.mCallback = callback;
         }
 
         @Override
         public boolean accept(org.chromium.mojo.bindings.Message message) {
             try {
                 org.chromium.mojo.bindings.ServiceMessage messageWithHeader =
                         message.asServiceMessage();
                 org.chromium.mojo.bindings.MessageHeader header = messageWithHeader.getHeader();
                 if (!header.validateHeader({{method|method_ordinal_name}},
                                            {{flags_for_method(method, False)}})) {
                     return false;
                 }
+{%   if method.response_parameters|length %}
                 {{response_struct|name}} response = {{response_struct|name}}.deserialize(messageWithHeader.getPayload());
+{%   endif %}
                 mCallback.call({{run_callback('response', method.response_parameters)}});
                 return true;
             } catch (org.chromium.mojo.bindings.DeserializationException e) {
                 return false;
             }
         }
     }
 
     static class {{response_struct|name}}ProxyToResponder implements {{interface|name}}.{{method|interface_response_name}} {
 
         private final org.chromium.mojo.system.Core mCore;
         private final org.chromium.mojo.bindings.MessageReceiver mMessageReceiver;
         private final long mRequestId;
 
         {{response_struct|name}}ProxyToResponder(
                 org.chromium.mojo.system.Core core,
                 org.chromium.mojo.bindings.MessageReceiver messageReceiver,
                 long requestId) {
             mCore = core;
             mMessageReceiver = messageReceiver;
             mRequestId = requestId;
         }
 
         @Override
         public void call({{declare_params(method.response_parameters, true)}}) {
-            {{response_struct|name}} response = new {{response_struct|name}}();
+            {{response_struct|name}} _response = new {{response_struct|name}}();
 {%   for param in method.response_parameters %}
-            response.{{param|name}} = {{param|name}};
+            _response.{{param|name}} = {{param|name}};
 {%   endfor %}
-            org.chromium.mojo.bindings.ServiceMessage message =
-                    response.serializeWithHeader(
+            org.chromium.mojo.bindings.ServiceMessage _message =
+                    _response.serializeWithHeader(
                             mCore,
                             new org.chromium.mojo.bindings.MessageHeader(
                                     {{method|method_ordinal_name}},
                                     {{flags_for_method(method, False)}},
                                     mRequestId));
-            mMessageReceiver.accept(message);
+            mMessageReceiver.accept(_message);
         }
     }
 {%   endif %}
 {% endfor %}
 
 }
 {% endmacro %}