org.apache.sshd.common.io.IoSession Maven / Gradle / Ivy
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* 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.sshd.common.io;
import java.io.IOException;
import java.net.SocketAddress;
import org.apache.sshd.common.Closeable;
import org.apache.sshd.common.future.CloseFuture;
import org.apache.sshd.common.util.buffer.Buffer;
import org.apache.sshd.common.util.net.ConnectionEndpointsIndicator;
public interface IoSession extends ConnectionEndpointsIndicator, Closeable {
/**
* @return a unique identifier for this session. Every session has its own ID which is different from any other.
*/
long getId();
/**
* @return The service address through which this session was accepted - {@code null} if session was initiated by
* this peer instead of being accepted
*/
SocketAddress getAcceptanceAddress();
/**
* Returns the value of the user-defined attribute of this session.
*
* @param key the key of the attribute
* @return {@code null} if there is no attribute with the specified key
*/
Object getAttribute(Object key);
/**
* Sets a user-defined attribute.
*
* @param key the key of the attribute
* @param value the value of the attribute
* @return The old value of the attribute - {@code null} if it is new.
*/
Object setAttribute(Object key, Object value);
/**
* Sets a user defined attribute if the attribute with the specified key is not set yet. This method is same with
* the following code except that the operation is performed atomically.
*
*
*
* if (containsAttribute(key)) {
* return getAttribute(key);
* } else {
* return setAttribute(key, value);
* }
*
*
*
* @param key The key of the attribute we want to set
* @param value The value we want to set
* @return The old value of the attribute - {@code null} if not found.
*/
Object setAttributeIfAbsent(Object key, Object value);
/**
* Removes a user-defined attribute with the specified key.
*
* @param key The key of the attribute we want to remove
* @return The old value of the attribute - {@code null} if not found.
*/
Object removeAttribute(Object key);
/**
* Write a packet on the socket. Multiple writes can be issued concurrently and will be queued.
*
* @param buffer the buffer send. NOTE: the buffer must not be touched until the returned write future
* is completed.
* @return An {@code IoWriteFuture} that can be used to check when the packet has actually been sent
* @throws IOException if an error occurred when sending the packet
*/
IoWriteFuture writeBuffer(Buffer buffer) throws IOException;
/**
* Closes this session immediately or after all queued write requests are flushed. This operation is asynchronous.
* Wait for the returned {@link CloseFuture} if you want to wait for the session actually closed.
*
* @param immediately {@code true} to close this session immediately. The pending write requests will simply be
* discarded. {@code false} to close this session after all queued write requests are flushed.
* @return The generated {@link CloseFuture}
*/
@Override
CloseFuture close(boolean immediately);
/**
* @return the {@link IoService} that created this session.
*/
IoService getService();
/**
* Handle received EOF.
*
* @throws IOException If failed to shutdown the stream
*/
void shutdownOutputStream() throws IOException;
/**
* Suspend read operations on this session. May do nothing if not supported by the session implementation.
*
* If the session usage includes a graceful shutdown with messages being exchanged, the caller needs to take care of
* resuming reading the input in order to actually be able to carry on the conversation with the peer.
*/
default void suspendRead() {
// Do nothing by default, but can be overriden by implementations
}
/**
* Resume read operations on this session. May do nothing if not supported by the session implementation.
*/
default void resumeRead() {
// Do nothing by default, but can be overriden by implementations
}
}