When a method such as list(), listBindings(), or search() returns a NamingEnumeration, any exceptions encountered are reserved until all results have been returned. At the end of the enumeration, the exception is thrown (by hasMore());
For example, if the list() is returning only a partial answer, the corresponding exception would be PartialResultException. list() would first return a NamingEnumeration. When the last of the results has been returned by the NamingEnumeration's next(), invoking hasMore() would result in PartialResultException being thrown.
In another example, if a search() method was invoked with a specified size limit of 'n'. If the answer consists of more than 'n' results, search() would first return a NamingEnumeration. When the n'th result has been returned by invoking next() on the NamingEnumeration, a SizeLimitExceedException would then thrown when hasMore() is invoked.
Note that if the program uses hasMoreElements() and nextElement() instead to iterate through the NamingEnumeration, because these methods cannot throw exceptions, no exception will be thrown. Instead, in the previous example, after the n'th result has been returned by nextElement(), invoking hasMoreElements() would return false.
Note also that NoSuchElementException is thrown if the program invokes next() or nextElement() when there are no elements left in the enumeration. The program can always avoid this exception by using hasMore() and hasMoreElements() to check whether the end of the enumeration has been reached.
If an exception is thrown during an enumeration, the enumeration becomes invalid. Subsequent invocation of any method on that enumeration will yield undefined results.
Context#list, Context#listBindings, javax.naming.directory.DirContext#search , javax.naming.directory.Attributes#getAll , javax.naming.directory.Attributes#getIDs , javax.naming.directory.Attribute#getAll
| Modifier and Type | Method and Description |
|---|---|
| public void | |
| public boolean | Returns: true if there is more in the enumeration ; false otherwise.Determines whether there are any more elements in the enumeration. |
| public T | Returns: The possibly null element in the enumeration. null is only valid for enumerations that can return null (e.g. Attribute.getAll() returns an enumeration of attribute values, and an attribute value can be null).Retrieves the next element in the enumeration. |
| close | back to summary |
|---|---|
| public void close() throws NamingException Closes this enumeration.
After this method has been invoked on this enumeration, the
enumeration becomes invalid and subsequent invocation of any of
its methods will yield undefined results.
This method is intended for aborting an enumeration to free up resources.
If an enumeration proceeds to the end--that is, until
This method indicates to the service provider that it is free
to release resources associated with the enumeration, and can
notify servers to cancel any outstanding requests. The
| |
| hasMore | back to summary |
|---|---|
| public boolean hasMore() throws NamingException Determines whether there are any more elements in the enumeration. This method allows naming exceptions encountered while determining whether there are more elements to be caught and handled by the application.
| |
| next | back to summary |
|---|---|
| public T next() throws NamingException Retrieves the next element in the enumeration. This method allows naming exceptions encountered while retrieving the next element to be caught and handled by the application.
Note that
| |