feat(java-client): find descriptors by proto fullname (#122)

Author: h4rikris

clients/java/src/main/java/io/odpf/stencil/DescriptorMapBuilder.java

@@ -51,24 +51,27 @@ public static Map<String, Descriptors.Descriptor> buildFrom(InputStream stream)
         fileDescriptors.forEach(fd -> {
             String javaPackage = fd.getOptions().getJavaPackage();
             String protoPackage = fd.getPackage();
-            fd.getMessageTypes().stream().forEach(desc -> descriptorMap.putAll(getFlattenedDescriptors(desc, javaPackage, protoPackage, "", new HashMap<>())));
+            fd.getMessageTypes().stream().forEach(desc -> descriptorMap.putAll(getFlattenedDescriptors(desc, javaPackage, protoPackage, new HashMap<>())));
         });
 
         return descriptorMap;
     }
 
-    private static Map<String, Descriptors.Descriptor> getFlattenedDescriptors(Descriptors.Descriptor descriptor, String javaPackage, String protoPackage, String parentClassName, Map<String, Descriptors.Descriptor> initialDescriptorMap) {
-        String className = getClassName(descriptor, parentClassName);
-        String javaClassName = javaPackage.isEmpty() ? className : String.format("%s.%s", javaPackage, className);
-        initialDescriptorMap.put(javaClassName, descriptor);
+    private static Map<String, Descriptors.Descriptor> getFlattenedDescriptors(Descriptors.Descriptor descriptor, String javaPackage, String protoPackage, Map<String, Descriptors.Descriptor> initialDescriptorMap) {
+        String fullName = descriptor.getFullName();
+        initialDescriptorMap.put(fullName, descriptor);
+        if (!javaPackage.isEmpty() && !javaPackage.equals(protoPackage)) {
+            initialDescriptorMap.put(getClassName(descriptor, protoPackage, javaPackage), descriptor);
+        }
         descriptor.getNestedTypes()
-                .forEach(desc -> getFlattenedDescriptors(desc, javaPackage, protoPackage, className, initialDescriptorMap));
+                .forEach(desc -> getFlattenedDescriptors(desc, javaPackage, protoPackage, initialDescriptorMap));
         return initialDescriptorMap;
     }
 
-
-    private static String getClassName(Descriptors.Descriptor descriptor, String parentClassName) {
-        return parentClassName.isEmpty() ? descriptor.getName() : parentClassName + "." + descriptor.getName();
+    private static String getClassName(Descriptors.Descriptor descriptor, String protoPackage, String javaPackage) {
+        if (protoPackage.isEmpty()) {
+            return String.format("%s.%s", javaPackage, descriptor.getFullName());
+        }
+        return descriptor.getFullName().replaceFirst(protoPackage, javaPackage);
     }
-
 }

clients/java/src/test/java/io/odpf/stencil/DescriptorMapBuilderTest.java

@@ -65,4 +65,30 @@ public void TestDescriptorsWithoutPackageName() throws IOException, Descriptors.
         assertEquals(".RootField", String.format(".%s", protoWithoutPackage.getFullName()));
     }
 
+    @Test
+    public void TestDescriptorsByProtoFullName() throws IOException, Descriptors.DescriptorValidationException {
+        ClassLoader classLoader = getClass().getClassLoader();
+        String descriptorFilePath = "__files/descriptors.bin";
+        InputStream fileInputStream = new FileInputStream(Objects.requireNonNull(classLoader.getResource(descriptorFilePath)).getFile());
+        Map<String, Descriptors.Descriptor> descriptorMap = DescriptorMapBuilder.buildFrom(fileInputStream);
+
+        final Descriptors.Descriptor protoWithoutJavaPackage = descriptorMap.get("io.odpf.stencil.ImplicitOuterClass");
+        assertNotNull(protoWithoutJavaPackage);
+        assertEquals("io.odpf.stencil.ImplicitOuterClass", protoWithoutJavaPackage.getFullName());
+    }
+
+    @Test
+    public void TestDescriptorsByProtoFullNameOrJavaName() throws IOException, Descriptors.DescriptorValidationException {
+        ClassLoader classLoader = getClass().getClassLoader();
+        String descriptorFilePath = "__files/descriptors.bin";
+        InputStream fileInputStream = new FileInputStream(Objects.requireNonNull(classLoader.getResource(descriptorFilePath)).getFile());
+        Map<String, Descriptors.Descriptor> descriptorMap = DescriptorMapBuilder.buildFrom(fileInputStream);
+
+        Descriptors.Descriptor protoWithoutPackage = descriptorMap.get("io.odpf.stencil.RootField");
+        assertEquals("RootField", protoWithoutPackage.getFullName());
+        Descriptors.Descriptor descriptorByProtoName = descriptorMap.get("RootField");
+        assertNotNull(descriptorByProtoName);
+        assertEquals(protoWithoutPackage, descriptorByProtoName);
+    }
+
 }

clients/java/src/test/proto/ProtoWithoutJavaPackage.proto

@@ -0,0 +1,10 @@
+syntax = "proto3";
+
+package io.odpf.stencil;
+
+message ImplicitOuterClass {
+    string sample_string = 1;
+    message Inner {
+      string one = 1;
+    }
+}