Support nested messages (#1)

src/main/java/io/github/stefanka/protobufgen/model/Message.java

@@ -18,9 +18,7 @@
 import io.github.stefanka.protobufgen.exception.FieldAlreadyExistsException;
 import io.github.stefanka.protobufgen.exception.FieldNumberAlreadyExistsException;
 
-import java.util.Objects;
-import java.util.Set;
-import java.util.TreeSet;
+import java.util.*;
 
 /**
  * Represents a protocol buffer message.
@@ -32,17 +30,28 @@ public class Message implements FieldType, Identifiable {
     private Identifier name;
     private String comment;
     private Set<MessageField> fields;
+    private List<Message> nestedMessages;
+    private Message parent;
 
     private Message() {
         // use builder to create message
     }
 
     /**
-     * Returns the name of the message as string.
+     * Returns the full name of the message (including parents, if it is a nested message) as string.
      *
-     * @return the name of the represented message
+     * @return the full name of the represented message
      */
     public String getName() {
+        return isNestedMessage() ? parent.getName() + "." + name.toString() : name.toString();
+    }
+
+    /**
+     * Returns the simple name of the message (without parents, if it is a nested message) as string
+     *
+     * @return the simple name of the represented message
+     */
+    public String getSimpleName() {
         return name.toString();
     }
 
@@ -74,16 +83,55 @@ public Set<MessageField> getFields() {
         return new TreeSet<>(fields);
     }
 
+    /**
+     * Returns the nested messages inside the represented message.
+     *
+     * @return a list with the nested messages inside the represented message
+     */
+    public List<Message> getNestedMessages() {
+        return new LinkedList<>(nestedMessages);
+    }
+
+    /**
+     * Indicates whether the represented message is a nested message or not.
+     *
+     * @return true if the message is a nested message, false otherwise
+     */
+    public boolean isNestedMessage() {
+        return parent != null;
+    }
+
+    /**
+     * Gives the parent message, in case the represented message is a nested message, null otherwise.
+     *
+     * @return the parent message of the nested message, or null if it is not a nested message
+     */
+    public Message getParent() {
+        return parent;
+    }
+
+    /**
+     * Changes the parent message of the represented message.
+     *
+     * @param parent the new parent message
+     */
+    protected void setParent(Message parent) {
+        this.parent = parent;
+    }
+
     public static class Builder {
         private final Identifier name;
         private final Set<MessageField> messageFields;
+        private final List<Message> nestedMessages;
         private String comment;
         private int fieldCounter = 1;
+        private Message parent;
 
         public Builder(String messageName) {
             this.name = new Identifier(messageName);
             this.comment = "";
             this.messageFields = new TreeSet<>();
+            this.nestedMessages = new LinkedList<>();
         }
 
         public Builder withComment(String comment) {
@@ -111,10 +159,19 @@ public Builder withField(FieldType type, String name) {
             return this;
         }
 
+        public Builder withNestedMessage(Message message) {
+            this.nestedMessages.add(message);
+            return this;
+        }
+
         public Message build() {
             Message message = new Message();
             message.name = this.name;
             message.fields = new TreeSet<>(this.messageFields);
+            message.nestedMessages = new LinkedList<>(this.nestedMessages);
+            for (Message nested : nestedMessages) {
+                nested.setParent(message);
+            }
             message.comment = this.comment;
             return message;
         }

src/main/resources/template/proto.ftl

@@ -10,15 +10,26 @@ import <#if import.isPublic()>public </#if>"${import.fileName}";
 <#if importStatements?has_content>
 
 </#if>
-<#list messages as message>
+<#macro renderMessage message indent>
 <#if message.comment?has_content>
-/* ${message.comment} */
+${""?left_pad(indent * 2)}/* ${message.comment} */
 </#if>
-message ${message.name} {
-  <#list message.fields as field>
-  <#if field.repeated>repeated </#if>${field.type} ${field.name} = ${field.number};<#if field.comment?has_content> // ${field.comment}</#if>
-  </#list>
-}
+${""?left_pad(indent * 2)}message ${message.simpleName} {
+<#if message.fields?has_content>
+<#list message.fields as field>
+${""?left_pad((indent + 1) * 2)}<#if field.repeated>repeated </#if>${field.type} ${field.name} = ${field.number};<#if field.comment?has_content> // ${field.comment}</#if>
+</#list>
+</#if>
+<#if message.getNestedMessages()?has_content>
+
+<#list message.getNestedMessages() as message>
+<@renderMessage message indent + 1 />
+</#list>
+</#if>
+${""?left_pad(indent * 2)}}
+</#macro>
+<#list messages as message>
+<@renderMessage message 0 />
 
 </#list>
 <#list enums as enum>

src/test/java/io/github/stefanka/protobufgen/model/MessageTest.java

@@ -122,6 +122,47 @@ public void canGiveFieldNumbersAutomatically() {
         assertEquals(2, message.getFields().stream().filter(f -> f.getName().equals("testField2")).map(f -> f.getNumber()).findAny().get());
     }
 
+    @Test
+    public void canNestMessages() {
+        // given
+        Message.Builder parentMessage = new Message.Builder("ParentMessage");
+        Message.Builder childMessage = new Message.Builder("ChildMessage");
+
+        // when
+        Message child = childMessage.build();
+        Message parent = parentMessage.withNestedMessage(child).build();
+
+        // then
+        assertEquals(1, parent.getNestedMessages().size());
+        assertTrue(child.isNestedMessage());
+        assertEquals("ParentMessage", child.getParent().getName());
+        assertEquals("ParentMessage.ChildMessage", child.getName());
+    }
+
+    @Test
+    public void canNestNestedMessages() {
+        // given
+        Message.Builder parentMessage = new Message.Builder("ParentMessage");
+        Message.Builder childMessage = new Message.Builder("ChildMessage");
+        Message.Builder childChildMessage = new Message.Builder("ChildChildMessage");
+
+        // when
+        Message childChild = childChildMessage.build();
+        Message child = childMessage.withNestedMessage(childChild).build();
+        Message parent = parentMessage.withNestedMessage(child).build();
+
+        // then
+        assertEquals(1, parent.getNestedMessages().size());
+        assertEquals(1, child.getNestedMessages().size());
+        assertTrue(child.isNestedMessage());
+        assertTrue(childChild.isNestedMessage());
+        assertEquals("ParentMessage", child.getParent().getName());
+        assertEquals("ParentMessage.ChildMessage", childChild.getParent().getName());
+        assertEquals("ParentMessage.ChildMessage.ChildChildMessage", childChild.getName());
+        assertEquals("ChildMessage", childChild.getParent().getSimpleName());
+        assertEquals("ChildChildMessage", childChild.getSimpleName());
+    }
+
     @Test
     public void canDetermineEquality() {
         // given

src/test/java/io/github/stefanka/protobufgen/serializer/ProtoSpecSerializerTest.java

@@ -134,6 +134,39 @@ public void canSerializeStreamsKeywordsInRPC() throws IOException {
         assertEquals(readIntegTestFile("streams-test.proto"), proto);
     }
 
+    @Test
+    public void canSerializeNestedMessages() throws IOException {
+        // given
+        Message childChild = new Message.Builder("ChildChild")
+                .withField(STRING, "name")
+                .build();
+        Message child = new Message.Builder("Child")
+                .withField(STRING, "name")
+                .withNestedMessage(childChild)
+                .build();
+        Message parent = new Message.Builder("Parent")
+                .withField(STRING, "name")
+                .withNestedMessage(child)
+                .build();
+        Message refs = new Message.Builder("Refs")
+                .withField(STRING, "name")
+                .withField(parent, "ref1")
+                .withField(child, "ref2")
+                .withField(childChild, "ref3")
+                .build();
+        ProtoSpec spec = new ProtoSpec.Builder()
+                .withPackage("integTests.NestedTest")
+                .withMessage(parent)
+                .withMessage(refs)
+                .build();
+
+        // when
+        String proto = new ProtoSpecSerializer().serialize(spec);
+
+        // then
+        assertEquals(readIntegTestFile("nested-test.proto"), proto);
+    }
+
     @Test
     public void canWriteToFile() throws IOException {
         // given

src/test/resources/integTests/nested-test.proto

@@ -0,0 +1,23 @@
+syntax = "proto3";
+
+package integTests.NestedTest;
+
+message Parent {
+  string name = 1;
+
+  message Child {
+    string name = 1;
+
+    message ChildChild {
+      string name = 1;
+    }
+  }
+}
+
+message Refs {
+  string name = 1;
+  Parent ref1 = 2;
+  Parent.Child ref2 = 3;
+  Parent.Child.ChildChild ref3 = 4;
+}
+