| /* |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| */ |
| |
| package org.apache.qpid.proton.reactor; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| |
| /** |
| * A multiplexor of instances of {@link Selectable}. |
| * <p> |
| * Many instances of <code>Selectable</code> can be added to a selector, and |
| * the {@link #select(long)} method used to block the calling thread until |
| * one of the <code>Selectables</code> becomes read to perform an operation. |
| * <p> |
| * This class is not thread safe, so only one thread should be manipulating the |
| * contents of the selector, or running the {@link #select(long)} method at |
| * any given time. |
| */ |
| public interface Selector { |
| |
| /** |
| * Adds a selectable to the selector. |
| * @param selectable |
| * @throws IOException |
| */ |
| void add(Selectable selectable) throws IOException; |
| |
| /** |
| * Updates the selector to reflect any changes interest by the specified |
| * selectable. This is achieved by calling the |
| * {@link Selectable#isReading()} and {@link Selectable#isWriting()} |
| * methods. |
| * @param selectable |
| */ |
| void update(Selectable selectable); |
| |
| /** |
| * Removes a selectable from the selector. |
| * @param selectable |
| */ |
| void remove(Selectable selectable); |
| |
| /** |
| * Waits for the specified timeout period for one or more selectables to |
| * become ready for an operation. Selectables that become ready are |
| * returned by the {@link #readable()}, {@link #writeable()}, |
| * {@link #expired()}, or {@link #error()} methods. |
| * |
| * @param timeout the maximum number of milliseconds to block the calling |
| * thread waiting for a selectable to become ready for an |
| * operation. The value zero is interpreted as check but |
| * don't block. |
| * @throws IOException |
| */ |
| void select(long timeout) throws IOException; |
| |
| /** |
| * @return the selectables that have become readable since the last call |
| * to {@link #select(long)}. Calling <code>select</code> clears |
| * any previous values in this set before adding new values |
| * corresponding to those selectables that have become readable. |
| */ |
| Iterator<Selectable> readable(); |
| |
| /** |
| * @return the selectables that have become writable since the last call |
| * to {@link #select(long)}. Calling <code>select</code> clears |
| * any previous values in this set before adding new values |
| * corresponding to those selectables that have become writable. |
| */ |
| Iterator<Selectable> writeable(); |
| |
| /** |
| * @return the selectables that have expired since the last call |
| * to {@link #select(long)}. Calling <code>select</code> clears |
| * any previous values in this set before adding new values |
| * corresponding to those selectables that have now expired. |
| */ |
| Iterator<Selectable> expired(); |
| |
| /** |
| * @return the selectables that have encountered an error since the last |
| * call to {@link #select(long)}. Calling <code>select</code> |
| * clears any previous values in this set before adding new values |
| * corresponding to those selectables that have encountered an |
| * error. |
| */ |
| Iterator<Selectable> error() ; |
| |
| /** Frees the resources used by this selector. */ |
| void free(); |
| } |