1 files changed, 40 insertions, 11 deletions

diff --git a/src/io/DataWriter.java b/src/io/DataWriter.java
index 42d69f8..841b27d 100644
--- a/src/io/DataWriter.java
+++ b/src/io/DataWriter.java
@@ -1,20 +1,23 @@
 package io;
 
-import java.io.File;
+import java.io.FileInputStream;
 import java.io.FileNotFoundException;
-import java.io.FileWriter;
+import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.util.HashSet;
 import java.util.Scanner;
 import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import org.apache.commons.io.Charsets;
 import org.json.JSONException;
 import org.json.JSONObject;
 import provider.ResultListener;
 
 /**
- * This class writes the output data into seperate files.
+ * This class writes the JSON objects for tweets and users to (separate) files.
  *
  * @author Maurice Laveaux
  */
@@ -23,12 +26,12 @@ public class DataWriter implements ResultListener {
     /**
      * The writer for the tweet stream.
      */
-    private final FileWriter m_tweetWriter;
+    private final OutputStream m_tweetWriter;
 
     /**
      * the writer for the profile stream.
      */
-    private final FileWriter m_profileWriter;
+    private final OutputStream m_profileWriter;
 
     /**
      * the buffer of tweet ids that already exist.
@@ -53,10 +56,34 @@ public class DataWriter implements ResultListener {
     public DataWriter(final String profilesName, final String tweetsName)
             throws IOException {
         m_profileIdSet = readIds(profilesName);
-        m_profileWriter = new FileWriter(profilesName, true);
+        m_profileWriter = getFileWriter(profilesName);
 
         m_tweetIdSet = readIds(tweetsName);
-        m_tweetWriter = new FileWriter(tweetsName, true);
+        m_tweetWriter = getFileWriter(tweetsName);
+    }
+
+    /**
+     * Given a filename, return a suitable input stream.
+     *
+     * @param tweetsName File name.
+     * @return A stream from which JSON objects can be read (one per line).
+     * @throws IOException
+     */
+    protected InputStream getFileReader(String tweetsName)
+            throws IOException {
+        return new FileInputStream(tweetsName);
+    }
+
+    /**
+     * Given a filename, return a suitable output stream.
+     *
+     * @param tweetsName File name.
+     * @return A stream to which JSON objects can be written (one per line).
+     * @throws IOException
+     */
+    protected OutputStream getFileWriter(String tweetsName)
+            throws IOException {
+        return new FileOutputStream(tweetsName, true);
     }
 
     public void close() {
@@ -88,7 +115,8 @@ public class DataWriter implements ResultListener {
     private Set readIds(String filename) throws IOException {
         Set<Long> idSet = new HashSet<>();
         try {
-            Scanner reader = new Scanner(new File(filename));
+            InputStream is = getFileReader(filename);
+            Scanner reader = new Scanner(is);
             // parse each line into a JSONObject, read the id and add it to
             // the set of ids.
             while (reader.hasNext()) {
@@ -109,17 +137,18 @@ public class DataWriter implements ResultListener {
      * Writes the JSONObject to a writer and update the idSet.
      *
      * @param obj The object to write.
-     * @param writer The writer object to append the object to.
+     * @param output The stream to write objects to.
      * @param idSet The id set to add the obj id to.
      */
-    private void writeObject(JSONObject obj, FileWriter writer, Set<Long> idSet) {
+    private void writeObject(JSONObject obj, OutputStream output,
+            Set<Long> idSet) {
         try {
             long id = obj.getLong("id");
 
             if (!idSet.contains(id)) {
                 // Write a single profile into the profile file.
                 try {
-                    writer.write(obj.toString() + "\n");
+                    output.write((obj.toString() + "\n").getBytes(Charsets.UTF_8));
                     idSet.add(id);
                 } catch (IOException ex) {
                     getLogger().log(Level.WARNING, "Cannot write to file", ex);