Add support for $ref

src/main/java/com/github/fge/jsonschema2avro/AvroWriterProcessor.java

@@ -24,13 +24,7 @@
 import com.github.fge.jsonschema.core.report.ProcessingReport;
 import com.github.fge.jsonschema.core.tree.SchemaTree;
 import com.github.fge.jsonschema.core.util.ValueHolder;
-import com.github.fge.jsonschema2avro.writers.ArrayWriter;
-import com.github.fge.jsonschema2avro.writers.EnumWriter;
-import com.github.fge.jsonschema2avro.writers.MapWriter;
-import com.github.fge.jsonschema2avro.writers.RecordWriter;
-import com.github.fge.jsonschema2avro.writers.SimpleTypeWriter;
-import com.github.fge.jsonschema2avro.writers.SimpleUnionWriter;
-import com.github.fge.jsonschema2avro.writers.TypeUnionWriter;
+import com.github.fge.jsonschema2avro.writers.*;
 import org.apache.avro.Schema;
 
 import static com.github.fge.jsonschema2avro.predicates.AvroPredicates.*;
@@ -50,6 +44,7 @@ public AvroWriterProcessor()
             .when(record()).then(new RecordWriter())
             .when(simpleUnion()).then(SimpleUnionWriter.getInstance())
             .when(typeUnion()).then(TypeUnionWriter.getInstance())
+            .when(typeRef()).then(RefWriter.getInstance())
             .getProcessor();
     }
 

src/main/java/com/github/fge/jsonschema2avro/predicates/AvroPredicates.java

@@ -211,6 +211,18 @@ public boolean apply(final AvroPayload input)
         };
     }
 
+    public static Predicate<AvroPayload> typeRef()
+    {
+        return new Predicate<AvroPayload>()
+        {
+            @Override
+            public boolean apply(final AvroPayload input)
+            {
+                return schemaNode(input).path("$ref").isTextual();
+            }
+        };
+    }
+
     private static JsonNode schemaNode(final AvroPayload payload)
     {
         return payload.getTree().getNode();

src/main/java/com/github/fge/jsonschema2avro/writers/RefWriter.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2014, Francis Galiegue ([email protected])
+ *
+ * This software is dual-licensed under:
+ *
+ * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
+ *   later version;
+ * - the Apache Software License (ASL) version 2.0.
+ *
+ * The text of both licenses is available under the src/resources/ directory of
+ * this project (under the names LGPL-3.0.txt and ASL-2.0.txt respectively).
+ *
+ * Direct link to the sources:
+ *
+ * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
+ * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+
+package com.github.fge.jsonschema2avro.writers;
+
+import com.github.fge.jackson.jsonpointer.JsonPointer;
+import com.github.fge.jsonschema.core.exceptions.JsonReferenceException;
+import com.github.fge.jsonschema.core.exceptions.ProcessingException;
+import com.github.fge.jsonschema.core.ref.JsonRef;
+import com.github.fge.jsonschema.core.report.ProcessingReport;
+import com.github.fge.jsonschema.core.tree.SchemaTree;
+import com.github.fge.jsonschema.core.util.ValueHolder;
+import com.github.fge.jsonschema2avro.AvroWriterProcessor;
+import org.apache.avro.Schema;
+
+public final class RefWriter
+    extends AvroWriter
+{
+    private static final AvroWriter INSTANCE = new RefWriter();
+
+    private RefWriter()
+    {
+    }
+
+    public static AvroWriter getInstance()
+    {
+        return INSTANCE;
+    }
+
+    @Override
+    protected Schema generate(final AvroWriterProcessor writer,
+        final ProcessingReport report, final SchemaTree tree)
+        throws ProcessingException
+    {
+        JsonPointer ptr = extractJsonRef(tree).getPointer();
+        ValueHolder<SchemaTree> holder = ValueHolder.hold("schema", tree.setPointer(ptr));
+        return writer.process(report, holder).getValue();
+    }
+
+    private static JsonRef extractJsonRef(SchemaTree tree) {
+        String $ref = tree.getNode().get("$ref").textValue();
+        try {
+            return JsonRef.fromString($ref);
+        } catch (JsonReferenceException e) {
+            throw new IllegalStateException("Could not parse $ref " + $ref);
+        }
+    }
+}

src/test/java/com/github/fge/jsonschema2avro/RefTest.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2014, Francis Galiegue ([email protected])
+ *
+ * This software is dual-licensed under:
+ *
+ * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
+ *   later version;
+ * - the Apache Software License (ASL) version 2.0.
+ *
+ * The text of both licenses is available under the src/resources/ directory of
+ * this project (under the names LGPL-3.0.txt and ASL-2.0.txt respectively).
+ *
+ * Direct link to the sources:
+ *
+ * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
+ * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+
+package com.github.fge.jsonschema2avro;
+
+import java.io.IOException;
+
+public final class RefTest
+    extends AvroWriterProcessorTest
+{
+    public RefTest()
+        throws IOException
+    {
+        super("ref");
+    }
+}

src/test/resources/jsonschema2avro/ref.json

@@ -0,0 +1,25 @@
+[
+    {
+        "jsonSchema": {
+            "type": "object",
+            "definitions": {
+                "customNumber": {
+                    "type": "number"
+                }
+            },
+            "properties": {
+                "someNumber": {
+                    "$ref": "#/definitions/customNumber"
+                }
+            },
+            "additionalProperties": false
+        },
+        "avroSchema": {
+            "type": "record",
+            "name": "record0",
+            "fields": [
+                { "name": "someNumber", "type": "double" }
+            ]
+        }
+    }
+]