Adds the specified attribute value to this attribute set if it is not already present, first removing any existing value in the same attribute category as the specified attribute value (optional operation).

  Adds the specified attribute value to this attribute set if it is not
already present, first removing any existing value in the same
attribute category as the specified attribute value (optional
operation).
Returns: true if this attribute set changed as a result of the call, i.e., the given attribute value was not already a member of this attribute set.
Parameters:
- attribute - Attribute value to be added to this attribute set.
Throws:
- UnmodifiableSetException - (unchecked exception) Thrown if this attribute set does not support the add() operation.
- ClassCastException - (unchecked exception) Thrown if the attribute is not an instance of interface {@link DocAttribute DocAttribute}.
- NullPointerException - (unchecked exception) Thrown if the attribute is null.

  Adds all of the elements in the specified set to this attribute.

  Adds all of the elements in the specified set to this attribute. The outcome is the same as if the add(Attribute) operation had been applied to this attribute set successively with each element from the specified set. If none of the categories in the specified set are the same as any categories in this attribute set, the addAll() operation effectively modifies this attribute set so that its value is the union of the two sets.

The behavior of the addAll() operation is unspecified if the specified set is modified while the operation is in progress.

If the addAll() operation throws an exception, the effect on this attribute set's state is implementation dependent; elements from the specified set before the point of the exception may or may not have been added to this attribute set.
Returns: true if this attribute set changed as a result of the call.
Parameters:
- attributes - whose elements are to be added to this attribute set.
Throws:
- UnmodifiableSetException - (Unchecked exception) Thrown if this attribute set does not support the addAll() method.
- ClassCastException - (Unchecked exception) Thrown if some element in the specified set is not an instance of interface {@link DocAttribute DocAttribute}.
- NullPointerException - (Unchecked exception) Thrown if the specified set is null.
See Also: DocAttributeSet.add(Attribute),