working on new storage format

src/main/java/de/srsoftware/web4rail/moving/Car.java

@@ -1,14 +1,54 @@
 package de.srsoftware.web4rail.moving;
 
+import java.io.BufferedWriter;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map.Entry;
+
+import org.json.JSONObject;
+
 public class Car {
+	private static final String ID = "id";
+	private static final String NAME = "name";
+	private static final String LENGTH = "length";
+	private static HashMap<String,Car> cars = new HashMap<String, Car>();
 	public int length;
 	private String name;
+	private String id;
 	
 	public Car(String name) {
-		this.name = name;
+		this(name,null);
 	}
 	
+	public Car(String name, String id) {
+		this.name = name;
+		this.id = id == null ? ""+new Date().getTime() : id;
+		cars.put(this.id, this);
+	}
+	
+	public String id() {
+		return id;
+	}
+	
+	public JSONObject json() {
+		JSONObject json = new JSONObject();
+		json.put(ID,id);
+		json.put(NAME, name);
+		json.put(LENGTH, length);
+		return json;
+	}
+
 	String name(){
 		return name;
 	}
+
+	public static void saveAll(String filename) throws IOException {
+		BufferedWriter file = new BufferedWriter(new FileWriter(filename));
+		for (Entry<String, Car> entry: cars.entrySet()) {
+			file.write(entry.getValue().json()+"\n");
+		}
+		file.close();
+	}
 }