opendap/src/main/java/opendap/dap/AttributeTable.java
public final AttributeTable appendContainer(String clearname) {
        // return null if clearname already exists
        // FIXME! THIS SHOULD RETURN AN EXCEPTION!
        if (_attr.get(clearname) != null)
            return null;

        AttributeTable at = new AttributeTable(clearname);
        Attribute a = new Attribute(clearname, at);
        _attr.put(clearname, a);
        return at;
    }
public final AttributeTable appendContainer(String clearname) {
        // return null if clearname already exists
        // FIXME! THIS SHOULD RETURN AN EXCEPTION!
        if (_attr.get(clearname) != null)
            return null;

        AttributeTable at = new AttributeTable(clearname);
        Attribute a = new Attribute(clearname, at);
        _attr.put(clearname, a);
        return at;
    }
Create and append an attribute container to the table.
A container is another <code>AttributeTable</code> object.

@param clearname the name of the container to add.
@return A pointer to the new <code>AttributeTable</code> object, or null
if a container by that name already exists.