1 files changed, 75 insertions, 0 deletions
diff --git a/src/fjbg/ch/epfl/lamp/fjbg/JAttribute.java b/src/fjbg/ch/epfl/lamp/fjbg/JAttribute.java
new file mode 100644
index 0000000000..981fbfc645
--- /dev/null
+++ b/src/fjbg/ch/epfl/lamp/fjbg/JAttribute.java
@@ -0,0 +1,75 @@
+// $Id$
+
+package ch.epfl.lamp.fjbg;
+
+import java.io.*;
+import java.util.*;
+
+/**
+ * Abstract superclass for attributes which can be attached to various
+ * parts of a class file.
+ *
+ * @author Michel Schinz
+ * @version 1.0
+ */
+
+public abstract class JAttribute {
+    protected final int nameIdx;
+
+    static public void writeTo(List/*<JAttribute>*/ attrs, DataOutputStream stream)
+        throws IOException {
+        stream.writeShort(attrs.size());
+        Iterator attrsIt = attrs.iterator();
+        while (attrsIt.hasNext()) {
+            JAttribute attr = (JAttribute)attrsIt.next();
+            attr.writeTo(stream);
+        }
+    }
+
+    static public List/*<JAttribute>*/ readFrom(FJBGContext context,
+                                                JClass clazz,
+                                                Object owner,
+                                                DataInputStream stream)
+        throws IOException {
+        JAttributeFactory factory = context.getJAttributeFactory();
+        int count = stream.readShort();
+        ArrayList list = new ArrayList(count);
+        for (int i = 0; i < count; ++i)
+            list.add(factory.newInstance(clazz, owner, stream));
+        return list;
+    }
+
+    public JAttribute(FJBGContext context, JClass clazz) {
+        this.nameIdx = clazz.getConstantPool().addUtf8(getName());
+    }
+
+    public JAttribute(FJBGContext context, JClass clazz, String name) {
+        this.nameIdx = clazz.getConstantPool().addUtf8(name);
+    }
+
+    abstract public String getName();
+
+    /**
+     * Write the attribute to a stream.
+     */
+    public void writeTo(DataOutputStream stream) throws IOException {
+        int contentsSize = getSize();
+
+        stream.writeShort(nameIdx);
+        stream.writeInt(contentsSize);
+        int streamSizeBefore = stream.size();
+        writeContentsTo(stream);
+        int streamSizeDiff = stream.size() - streamSizeBefore;
+
+        assert contentsSize == streamSizeDiff
+            : "invalid size for attribute " + getName()
+            + " given: " + contentsSize
+            + " actual: " + streamSizeDiff;
+    }
+
+    // Note: it is not legal to add data to the constant pool during
+    // the execution of any of the following two methods.
+    protected abstract int getSize();
+    protected abstract void writeContentsTo(DataOutputStream stream)
+        throws IOException;
+}