| /* |
| * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.naming; |
| |
| import java.util.Enumeration; |
| |
| /** |
| * This interface is for enumerating lists returned by |
| * methods in the javax.naming and javax.naming.directory packages. |
| * It extends Enumeration to allow as exceptions to be thrown during |
| * the enumeration. |
| *<p> |
| * 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()); |
| * <p> |
| * 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. |
| *<p> |
| * 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. |
| *<p> |
| * 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. |
| *<p> |
| * 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. |
| *<p> |
| * If an exception is thrown during an enumeration, |
| * the enumeration becomes invalid. |
| * Subsequent invocation of any method on that enumeration |
| * will yield undefined results. |
| * |
| * @author Rosanna Lee |
| * @author Scott Seligman |
| * |
| * @see Context#list |
| * @see Context#listBindings |
| * @see javax.naming.directory.DirContext#search |
| * @see javax.naming.directory.Attributes#getAll |
| * @see javax.naming.directory.Attributes#getIDs |
| * @see javax.naming.directory.Attribute#getAll |
| * @since 1.3 |
| */ |
| public interface NamingEnumeration<T> extends Enumeration<T> { |
| /** |
| * 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. |
| * <p> |
| * Note that {@code next()} can also throw the runtime exception |
| * NoSuchElementException to indicate that the caller is |
| * attempting to enumerate beyond the end of the enumeration. |
| * This is different from a NamingException, which indicates |
| * that there was a problem in obtaining the next element, |
| * for example, due to a referral or server unavailability, etc. |
| * |
| * @return 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). |
| * @exception NamingException If a naming exception is encountered while attempting |
| * to retrieve the next element. See NamingException |
| * and its subclasses for the possible naming exceptions. |
| * @exception java.util.NoSuchElementException If attempting to get the next element when none is available. |
| * @see java.util.Enumeration#nextElement |
| */ |
| public T next() 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. |
| * |
| * @return true if there is more in the enumeration ; false otherwise. |
| * @exception NamingException |
| * If a naming exception is encountered while attempting |
| * to determine whether there is another element |
| * in the enumeration. See NamingException |
| * and its subclasses for the possible naming exceptions. |
| * @see java.util.Enumeration#hasMoreElements |
| */ |
| public boolean hasMore() 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 |
| * {@code hasMoreElements()} or {@code hasMore()} returns {@code false}-- |
| * resources will be freed up automatically and there is no need to |
| * explicitly call {@code close()}. |
| *<p> |
| * 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 {@code close()} |
| * method is a hint to implementations for managing their resources. |
| * Implementations are encouraged to use appropriate algorithms to |
| * manage their resources when client omits the {@code close()} calls. |
| * |
| * @exception NamingException If a naming exception is encountered |
| * while closing the enumeration. |
| * @since 1.3 |
| */ |
| public void close() throws NamingException; |
| } |
