Convert String to DateTime (for created_at)

Extra efforts are done to keep the timezone information.

1 files changed, 51 insertions, 0 deletions

diff --git a/src/utils/TwitterDateAdapter.java b/src/utils/TwitterDateAdapter.java
new file mode 100644
index 0000000..b3c8f37
--- /dev/null
+++ b/src/utils/TwitterDateAdapter.java
@@ -0,0 +1,51 @@
+package utils;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import java.lang.reflect.Type;
+import org.joda.time.DateTime;
+import org.joda.time.format.DateTimeFormat;
+import org.joda.time.format.DateTimeFormatter;
+
+/**
+ * Converts a Twitter date string to a DateTime with timezone.
+ *
+ * @author Peter Wu
+ */
+public class TwitterDateAdapter implements JsonDeserializer<DateTime>,
+        JsonSerializer<DateTime> {
+
+    private static final DateTimeFormatter DATE_FORMATTER
+            = DateTimeFormat.forPattern("EEE MMM dd HH:mm:ss Z yyyy")
+            .withOffsetParsed();
+
+    @Override
+    public DateTime deserialize(JsonElement je, Type type,
+            JsonDeserializationContext jdc) throws JsonParseException {
+        JsonPrimitive jp;
+        if (!je.isJsonPrimitive() || !(jp = je.getAsJsonPrimitive()).isString()) {
+            throw new JsonParseException("Invalid date type");
+        }
+        String datetime = jp.getAsString();
+        try {
+            return DATE_FORMATTER.parseDateTime(datetime);
+        } catch (IllegalArgumentException ex) {
+            throw new JsonParseException("Invalid date: " + datetime, ex);
+        }
+    }
+
+    @Override
+    public JsonElement serialize(DateTime t, Type type,
+            JsonSerializationContext jsc) {
+        return new JsonPrimitive(formatDateTime(t));
+    }
+
+    public static String formatDateTime(DateTime t) {
+        return DATE_FORMATTER.print(t);
+    }
+}