Use custom type for media fields.

Gson does not know how to serialize byte arrays, and it may be preferable to store paths rather than raw media.
Add custom type with fields for byte array and path and serializers for both.

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/media/SerializableMedia.java

@@ -0,0 +1,105 @@
+/**
+ * Copyright © 2010-2014 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jsonschema2pojo.media;
+
+import android.util.Base64;
+import com.google.gson.*;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
+import org.apache.commons.io.FileUtils;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Holder for media with Gson serializer adapters to either read/write path to media, or the media itself.
+ *
+ * @author Kathryn Killebrew
+ */
+public class SerializableMedia {
+    public byte[] data; // base64-encoded media
+    public String path; // URI
+
+    /**
+     * Reads/writes {@link SerializableMedia} via Gson as byte array.
+     *
+     * When reading, expects JSON value to be a byte array to set on {@link SerializableMedia#data} field.
+     * When writing, will use {@link SerializableMedia#data} if set; if not, it will attempt to resolve the
+     * URI in {@link SerializableMedia#path} if set
+     */
+    public static class SerializableMediaByteArrayAdapter extends TypeAdapter<SerializableMedia> {
+        public SerializableMedia read(JsonReader reader) throws IOException {
+            if (reader.peek() == JsonToken.NULL) {
+                reader.nextNull();
+                return null;
+            }
+            SerializableMedia newMedia = new SerializableMedia();
+            newMedia.data = Base64.decode(reader.nextString(), Base64.NO_WRAP);
+            return newMedia;
+        }
+
+        public void write(JsonWriter writer, SerializableMedia value) throws IOException {
+            if (value == null) {
+                writer.nullValue();
+                return;
+            }
+
+            // just use data field directly if set
+            if (value.data != null) {
+                writer.value(Base64.encodeToString(value.data, Base64.NO_WRAP));
+            }
+
+            // attempt to read in image at path into data
+            if (value.path != null && !value.path.isEmpty()) {
+                File file = new File(value.path);
+                writer.value(Base64.encodeToString(FileUtils.readFileToByteArray(file), Base64.NO_WRAP));
+                return;
+            }
+
+            writer.nullValue();
+        }
+    }
+
+    /**
+     * Reads/writes {@link SerializableMedia} via Gson as String that is a URI pointing to the media.
+     * Ignores the {@link SerializableMedia#data} field.
+     *
+     * When reading, expects JSON value to be a URI to set on the {@link SerializableMedia#path} field.
+     * When writing, writes string from {@link SerializableMedia#path} field, if set.
+     */
+    public static class SerializableMediaPathStringAdapter extends TypeAdapter<SerializableMedia> {
+        public SerializableMedia read(JsonReader reader) throws IOException {
+            if (reader.peek() == JsonToken.NULL) {
+                reader.nextNull();
+                return null;
+            }
+            SerializableMedia newMedia = new SerializableMedia();
+            newMedia.path = reader.nextString();
+            return newMedia;
+        }
+
+        public void write(JsonWriter writer, SerializableMedia value) throws IOException {
+            if (value == null || value.path == null || value.path.isEmpty()) {
+                writer.nullValue();
+                return;
+            }
+
+            writer.value(value.path);
+        }
+    }
+}

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/MediaRule.java

@@ -20,6 +20,7 @@
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.sun.codemodel.JType;
+import org.jsonschema2pojo.media.SerializableMedia;
 
 /**
  * <p>
@@ -63,7 +64,7 @@ protected MediaRule(RuleFactory ruleFactory) {
      *            the type with the media node.  This must be java.lang.String.
      * @param schema
      *            the schema containing the property.
-     * @return byte[] when a binary encoding is specified, baseType otherwise.
+     * @return {@link SerializableMedia} when a binary encoding is specified, baseType otherwise.
      * @since 0.4.2
      */
     @Override
@@ -72,6 +73,6 @@ public JType apply(String nodeName, JsonNode mediaNode, JType baseType, Schema s
             return baseType;
         }
 
-        return baseType.owner().ref(byte[].class);
+        return baseType.owner().ref(SerializableMedia.class);
     }
 }