Generate java method signatures in common code

generateJavaImpl and generateJava both need to generate method
signatures. This makes it so that they can call a method on "Method"
instead of having to add all the logic themselves.

Fixes: 132654975
Test: ./test/run_all_host_tests.sh && ./test/run_all_device_tests.sh
Change-Id: I60ef33da5658139a5f40d71d5e6f6c6a2bbdbee0
diff --git a/generateJava.cpp b/generateJava.cpp
index 1fe0634..577caf9 100644
--- a/generateJava.cpp
+++ b/generateJava.cpp
@@ -238,7 +238,6 @@
     iface->emitJavaTypeDeclarations(out, false /* atTopLevel */);
 
     for (const auto &method : iface->methods()) {
-        const bool returnsValue = !method->results().empty();
         const bool needsCallback = method->results().size() > 1;
 
         if (needsCallback) {
@@ -257,27 +256,9 @@
 
         method->emitDocComment(out);
 
-        if (returnsValue && !needsCallback) {
-            out << method->results()[0]->type().getJavaType();
-        } else {
-            out << "void";
-        }
+        method->emitJavaSignature(out);
 
-        out << " "
-            << method->name()
-            << "(";
-        method->emitJavaArgSignature(out);
-
-        if (needsCallback) {
-            if (!method->args().empty()) {
-                out << ", ";
-            }
-
-            out << method->name()
-                << "Callback _hidl_cb";
-        }
-
-        out << ")\n";
+        out << "\n";
         out.indent();
         out << "throws android.os.RemoteException;\n";
         out.unindent();
@@ -341,27 +322,9 @@
         const bool needsCallback = method->results().size() > 1;
 
         out << "@Override\npublic ";
-        if (returnsValue && !needsCallback) {
-            out << method->results()[0]->type().getJavaType();
-        } else {
-            out << "void";
-        }
+        method->emitJavaSignature(out);
 
-        out << " "
-            << method->name()
-            << "(";
-        method->emitJavaArgSignature(out);
-
-        if (needsCallback) {
-            if (!method->args().empty()) {
-                out << ", ";
-            }
-
-            out << method->name()
-                << "Callback _hidl_cb";
-        }
-
-        out << ")\n";
+        out << "\n";
         out.indent();
         out.indent();
         out << "throws android.os.RemoteException {\n";