sketch of serialization/deserialization code (broken)

classpath/java/io/ObjectOutputStream.java

@@ -1,10 +1,12 @@
 package java.io;
 
+import java.util.IdentityHashMap;
+
 public class ObjectOutputStream extends OutputStream {
-  private final OutputStream out;
+  private final PrintStream out;
 
   public ObjectOutputStream(OutputStream out) {
-    this.out = out;
+    this.out = new PrintStream(out);
   }
   
   public void write(int c) throws IOException {
@@ -22,5 +24,157 @@ public class ObjectOutputStream extends OutputStream {
   public void close() throws IOException {
     out.close();
   }
+
+  public void writeObject(Object o) throws IOException {
+    writeObject(o, new IdentityHashMap(), 0);
+  }
+
+  public void writeBoolean(boolean v) {
+    out.print("z");
+    out.print((v ? 1 : 0));
+  }
+
+  public void writeByte(byte v) {
+    out.print("b");
+    out.print((int) v);
+  }
+
+  public void writeChar(char v) {
+    out.print("c");
+    out.print((int) v);
+  }
+
+  public void writeShort(short v) {
+    out.print("s");
+    out.print((int) v);
+  }
+
+  public void writeInt(int v) {
+    out.print("i");
+    out.print(v);
+  }
+
+  public void writeLong(long v) {
+    out.print("j");
+    out.print(v);
+  }
+
+  public void writeFloat(float v) {
+    out.print("f");
+    out.print(v);
+  }
+
+  public void writeDouble(double v) {
+    out.print("d");
+    out.print(v);
+  }
+
+  private void writeObject(Object o, IdentityHashMap<Object, Integer> map,
+                           int nextId)
+    throws IOException
+  {
+    if (o == null) {
+      out.print("n");
+    } else {
+      Integer id = map.get(new Identity(o));
+      if (id == null) {
+        map.put(new Identity(o), nextId);
+
+        Class c = o.getClass();
+        if (c.isArray()) {
+          serializeArray(o, map, nextId);
+        } else if (Serializable.class.isAssignableFrom(c)) {
+          serialize(o, map, nextId);
+        } else {
+          throw new NotSerializableException(c.getName());
+        }
+      } else {
+        out.print("r");
+        out.print(id.intValue());
+      }
+    }
+  }
+
+  private void serializeArray(Object o, IdentityHashMap<Object, Integer> map,
+                              int nextId)
+    throws IOException
+  {
+    Class c = o.getClass();
+    Class t = c.getComponentType();
+    int length = Array.getLength(o);
+
+    out.print("a(");
+    out.print(nextId++);
+    out.print(" ");
+    out.print(c.getName());
+    out.print(" ");
+    out.print(length);
+
+    for (int i = 0; i < length; ++i) {
+      out.print(" ");
+      if (t.equals(boolean.class)) {
+        writeBoolean(Array.getBoolean(o));
+      } else if (t.equals(byte.class)) {
+        writeByte(Array.getByte(o));
+      } else if (t.equals(char.class)) {
+        writeChar(Array.getChar(o));
+      } else if (t.equals(short.class)) {
+        writeShort(Array.getShort(o));
+      } else if (t.equals(int.class)) {
+        writeInt(Array.getInt(o));
+      } else if (t.equals(long.class)) {
+        writeLong(Array.getLong(o));
+      } else if (t.equals(float.class)) {
+        writeFloat(Array.getFloat(o));
+      } else if (t.equals(double.class)) {
+        writeDouble(Array.getDouble(o));
+      } else {
+        writeObject(Array.get(o), map, nextId);
+      }
+    }
+
+    out.print(")");
+  }
+  
+  private void serialize(Object o, IdentityHashMap<Object, Integer> map,
+                         int nextId)
+    throws IOException
+  {
+    Class c = o.getClass();
+
+    out.print("l(");
+    out.print(nextId++);
+    out.print(" ");
+    out.print(c.getName());
+
+    for (Field f: c.getFields()) {
+      int modifiers = f.getModifiers();
+      if ((modifiers & (Modifier.TRANSIENT | Modifier.STATIC)) == 0) {
+        out.print(" ");
+        Class t = f.getType();
+        if (t.equals(boolean.class)) {
+          writeBoolean(f.getBoolean(o));
+        } else if (t.equals(byte.class)) {
+          writeByte(f.getByte(o));
+        } else if (t.equals(char.class)) {
+          writeChar(f.getChar(o));
+        } else if (t.equals(short.class)) {
+          writeShort(f.getShort(o));
+        } else if (t.equals(int.class)) {
+          writeInt(f.getInt(o));
+        } else if (t.equals(long.class)) {
+          writeLong(f.getLong(o));
+        } else if (t.equals(float.class)) {
+          writeFloat(f.getFloat(o));
+        } else if (t.equals(double.class)) {
+          writeDouble(f.getDouble(o));
+        } else {
+          writeObject(f.get(o), map, nextId);
+        }
+      }
+    }
+
+    out.print(")");
+  }
   
 }