The main refactoring

Document.php

@@ -1,49 +1,28 @@
 <?php
 class Document {
 
-    public $user;
+    private $user;
 
-    public $name;
+    private $name;
 
-    public function init($name, User $user) {
+    public function __construct($name, User $user) {
         assert(strlen($name) > 5);
         $this->user = $user;
         $this->name = $name;
     }
 
     public function getTitle() {
-        $db = Database::getInstance();
-        $row = $db->query('SELECT * FROM document WHERE name = "' . $this->name . '" LIMIT 1');
-        return $row[3]; // third column in a row
+        return $this->getColumn(3); // third column in a row
     }
 
     public function getContent() {
-        $db = Database::getInstance();
-        $row = $db->query('SELECT * FROM document WHERE name = "' . $this->name . '" LIMIT 1');
-        return $row[6]; // sixth column in a row
+        return $this->getColumn(6); // sixth column in a row
     }
 
-    public static function getAllDocuments() {
-        // to be implemented later
-    }
-
-}
-
-class User {
-
-    public function makeNewDocument($name) {
-        $doc = new Document();
-        $doc->init($name, $this);
-        return $doc;
-    }
-
-    public function getMyDocuments() {
-        $list = array();
-        foreach (Document::getAllDocuments() as $doc) {
-            if ($doc->user == $this)
-                $list[] = $doc;
-        }
-        return $list;
+    private function getColumn($column) {
+        $db = Database::getInstance();
+        $row = $db->query('SELECT * FROM document WHERE name = "' . $this->name . '" LIMIT 1');
+        return $row[$column]; // sixth column in a row
     }
 
 }

FileWithContent.java

@@ -0,0 +1,40 @@
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+/**
+ * This class is thread safe.
+ */
+public class FileWithContent {
+  private File file;
+  public FileWithContent(File f) {
+    this.file = f;
+  }
+  public String getContent() throws IOException {
+    return getContent(true);
+  }
+  public String getContentWithoutUnicode() throws IOException {
+    return getContent(false);
+  }
+  public synchronized void saveContent(String content) {
+    try (FileOutputStream o = new FileOutputStream(file)) {
+      for (int i = 0; i < content.length(); i += 1) {
+        o.write(content.charAt(i));
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+  private synchronized String getContent(boolean withUnicode) throws IOException {
+    try (FileInputStream i = new FileInputStream(file)) {
+      String output = "";
+      int data;
+      while ((data = i.read()) > 0) {
+        if(withUnicode || data >= 0x80) {
+          output += (char) data;
+        })
+      }
+      return output;
+    }
+  }
+}

User.php

@@ -0,0 +1,23 @@
+<?php
+class User {
+
+    private $id;
+
+    public function __construct($id) {
+        $this->id = $id;
+    }
+
+    public function createDocument($name) {
+        return new Document($name, $this);
+    }
+
+    public function getMyDocuments() {
+        $db = Database::getInstance();
+        $list = array();
+        foreach ($db->query('SELECT name FROM document WHERE user_id = ' . $this->id) as $name) {
+            $list[] = $this->createDocument($name);
+        }
+        return $list;
+    }
+
+}