/*
* SSHTools - Java SSH2 API
*
* Copyright (C) 2002-2003 Lee David Painter and Contributors.
*
* Contributions made by:
*
* Brett Smith
* Richard Pernavas
* Erwin Bolwidt
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package com.sshtools.j2ssh.transport;
import com.sshtools.j2ssh.io.ByteArrayReader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Vector;
/**
* <p>
* This class implements a message store that can be used to provide a blocking
* mechanism for transport protocol messages.
* </p>
*
* @author Lee David Painter
* @version $Revision: 1.42 $
*
* @since 0.2.0
*/
public final class SshMessageStore {
private static Log log = LogFactory.getLog(SshMessageStore.class);
// List to hold messages as they are received
private List messages = new ArrayList();
private Map register = new HashMap();
private boolean isClosed = false;
private int[] singleIdFilter = new int[1];
private int interrupt = 5000;
private Vector listeners = new Vector();
/**
* <p>
* Contructs the message store.
* </p>
*
* @since 0.2.0
*/
public SshMessageStore() {
}
/**
* <p>
* Evaluate whether the message store is closed.
* </p>
*
* @return
*
* @since 0.2.0
*/
public boolean isClosed() {
return isClosed;
}
public void addMessageListener(SshMessageListener listener) {
synchronized (listeners) {
listeners.add(listener);
}
}
/**
* <p>
* Get a message from the store. This method will block until a message
* with an id matching the supplied filter arrives, or the message store
* closes. The message is removed from the store.
* </p>
*
* @param messageIdFilter an array of message ids that are acceptable
*
* @return the next available message
*
* @throws MessageStoreEOFException if the message store is closed
* @throws InterruptedException if the thread was interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage getMessage(int[] messageIdFilter)
throws MessageStoreEOFException, InterruptedException {
try {
return getMessage(messageIdFilter, 0);
} catch (MessageNotAvailableException e) {
// This should never happen but throw just in case
throw new MessageStoreEOFException();
}
}
/**
* <p>
* Get a message from the store. This method will block until a message
* with an id matching the supplied filter arrives, the specified timeout
* is reached or the message store closes. The message is removed from the
* store.
* </p>
*
* @param messageIdFilter an array of message ids that are acceptable.
* @param timeout the maximum number of milliseconds to block before
* returning.
*
* @return the next available message
*
* @throws MessageStoreEOFException if the message store is closed
* @throws MessageNotAvailableException if the message is not available
* after a timeout
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage getMessage(int[] messageIdFilter, int timeout)
throws MessageStoreEOFException, MessageNotAvailableException,
InterruptedException {
if ((messages.size() <= 0) && isClosed) {
throw new MessageStoreEOFException();
}
if (messageIdFilter == null) {
return nextMessage();
}
SshMessage msg;
boolean firstPass = true;
if (timeout < 0) {
timeout = 0;
}
while ((messages.size() > 0) || !isClosed) {
// lookup the message
msg = lookupMessage(messageIdFilter, true);
if (msg != null) {
return msg;
} else {
// If this is the second time and there's no message, then throw
if (!firstPass && (timeout > 0)) {
throw new MessageNotAvailableException();
}
}
// Now wait
if (!isClosed) {
wait((timeout == 0) ? interrupt : timeout);
}
firstPass = false;
}
throw new MessageStoreEOFException();
}
/**
* <p>
* Get a message from the store. This method will block until a message
* with an id matching the supplied id arrives, or the message store
* closes. The message is removed from the store.
* </p>
*
* @param messageId the id of the message requried
*
* @return the next available message with the id supplied
*
* @throws MessageStoreEOFException if the message store closed
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage getMessage(int messageId)
throws MessageStoreEOFException, InterruptedException {
try {
return getMessage(messageId, 0);
} catch (MessageNotAvailableException e) {
// This should never happen by throw jsut in case
throw new MessageStoreEOFException();
}
}
/**
* <p>
* Get a message from the store. This method will block until a message
* with an id matching the supplied id arrives,the specified timeout is
* reached or the message store closes. The message will be removed from
* the store.
* </p>
*
* @param messageId the id of the message requried
* @param timeout the maximum number of milliseconds to block before
* returning.
*
* @return the next available message with the id supplied
*
* @throws MessageStoreEOFException if the message store closed
* @throws InterruptedException if the thread is interrupted
* @throws InterruptedException
*
* @since 0.2.0
*/
public synchronized SshMessage getMessage(int messageId, int timeout)
throws MessageStoreEOFException, MessageNotAvailableException,
InterruptedException {
singleIdFilter[0] = messageId;
return getMessage(singleIdFilter, timeout);
}
/**
* <p>
* Evaluate whether the store has any messages.
* </p>
*
* @return true if messages exist, otherwise false
*
* @since 0.2.0
*/
public boolean hasMessages() {
return messages.size() > 0;
}
/**
* <p>
* Returns the number of messages contained within this message store.
* </p>
*
* @return the number of messages
*
* @since 0.2.0
*/
public int size() {
return messages.size();
}
/**
* <p>
* Determines if the message id is a registered message of this store.
* </p>
*
* @param messageId the message id
*
* @return true if the message id is registered, otherwise false
*
* @since 0.2.0
*/
public boolean isRegisteredMessage(Integer messageId) {
return register.containsKey(messageId);
}
/**
* <p>
* Adds a raw message to the store and processes the data into a registered
* message.
* </p>
*
* @param msgdata the raw message data to process
*
* @throws MessageNotRegisteredException if the message id of the raw data
* is not a registered message
* @throws InvalidMessageException if the message is invalid
*
* @since 0.2.0
*/
public void addMessage(byte[] msgdata)
throws MessageNotRegisteredException, InvalidMessageException {
Integer messageId = new Integer(msgdata[5]);
if (!isRegisteredMessage(messageId)) {
throw new MessageNotRegisteredException(messageId);
}
Class cls = (Class) register.get(SshMessage.getMessageId(msgdata));
try {
SshMessage msg = (SshMessage) cls.newInstance();
msg.fromByteArray(new ByteArrayReader(msgdata));
addMessage(msg);
} catch (IllegalAccessException iae) {
throw new InvalidMessageException(
"Illegal access for implementation class " + cls.getName());
} catch (InstantiationException ie) {
throw new InvalidMessageException("Instantiation failed for class " +
cls.getName());
}
}
/**
* <p>
* Add a formed message to the store.
* </p>
*
* @param msg the message to add to the store
*
* @throws MessageNotRegisteredException if the message type is not
* registered with the store
*
* @since 0.2.0
*/
public synchronized void addMessage(SshMessage msg)
throws MessageNotRegisteredException {
// Add the message
messages.add(messages.size(), msg);
synchronized (listeners) {
if (listeners.size() > 0) {
for (Iterator it = listeners.iterator(); it.hasNext();) {
((SshMessageListener) it.next()).messageReceived(msg);
}
}
}
// Notify the threads
notifyAll();
}
/**
* <p>
* Closes the store. This will cause any blocking operations on the message
* store to return.
* </p>
*
* @since 0.2.0
*/
public synchronized void close() {
isClosed = true;
// We need to notify all anyway as if there are messages still available
// it should not affect the waiting threads as they are waiting for their
// own messages to be received because non were avaialable in the first place
//if (messages.size()<=0) {
notifyAll();
//}
}
/**
* <p>
* Get the next message in the store or wait until a new message arrives.
* The message is removed from the store.
* </p>
*
* @return the next available message.
*
* @throws MessageStoreEOFException if the message store is closed
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage nextMessage()
throws MessageStoreEOFException, InterruptedException {
if ((messages.size() <= 0) && isClosed) {
throw new MessageStoreEOFException();
}
// If there are no messages available then wait untill there are.
while ((messages.size() <= 0) && !isClosed) {
wait(interrupt);
}
if (messages.size() > 0) {
return (SshMessage) messages.remove(0);
} else {
throw new MessageStoreEOFException();
}
}
/**
*
*/
public synchronized void breakWaiting() {
notifyAll();
}
/**
* <p>
* Get a message from the store without removing or blocking if the message
* does not exist.
* </p>
*
* @param messageIdFilter the id of the message requried
*
* @return the next available message with the id supplied
*
* @throws MessageStoreEOFException if the message store closed
* @throws MessageNotAvailableException if the message is not available
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage peekMessage(int[] messageIdFilter)
throws MessageStoreEOFException, MessageNotAvailableException,
InterruptedException {
return peekMessage(messageIdFilter, 0);
}
/**
* <p>
* Get a message from the store without removing it; only blocking for the
* number of milliseconds specified in the timeout field. If timeout is
* zero, the method will not block.
* </p>
*
* @param messageIdFilter an array of acceptable message ids
* @param timeout the number of milliseconds to wait
*
* @return the next available message of the acceptable message ids
*
* @throws MessageStoreEOFException if the message store is closed
* @throws MessageNotAvailableException if the message is not available
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage peekMessage(int[] messageIdFilter,
int timeout)
throws MessageStoreEOFException, MessageNotAvailableException,
InterruptedException {
SshMessage msg;
// Do a straight lookup
msg = lookupMessage(messageIdFilter, false);
if (msg != null) {
return msg;
}
// If were willing to wait the wait and look again
if (timeout > 0) {
if (log.isDebugEnabled()) {
log.debug("No message so waiting for " +
String.valueOf(timeout) + " milliseconds");
}
wait(timeout);
msg = lookupMessage(messageIdFilter, false);
if (msg != null) {
return msg;
}
}
// Nothing even after a wait so throw the relevant exception
if (isClosed) {
throw new MessageStoreEOFException();
} else {
throw new MessageNotAvailableException();
}
}
private SshMessage lookupMessage(int[] messageIdFilter, boolean remove) {
SshMessage msg;
for (int x = 0; x < messages.size(); x++) {
msg = (SshMessage) messages.get(x);
// Determine whether its one of the filtered messages
for (int i = 0; i < messageIdFilter.length; i++) {
if (msg.getMessageId() == messageIdFilter[i]) {
if (remove) {
messages.remove(msg);
}
return msg;
}
}
}
return null;
}
/**
* <p>
* Get a message from the store without removing it.
* </p>
*
* @param messageId the acceptable message id
*
* @return the next available message.
*
* @throws MessageStoreEOFException if the message store is closed.
* @throws MessageNotAvailableException if the message is not available.
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage peekMessage(int messageId)
throws MessageStoreEOFException, MessageNotAvailableException,
InterruptedException {
return peekMessage(messageId, 0);
}
/**
* <p>
* Removes a message from the message store.
* </p>
*
* @param msg the message to remove
*
* @since 0.2.0
*/
public synchronized void removeMessage(SshMessage msg) {
messages.remove(msg);
}
/**
* <p>
* Get a message from the store without removing it, only blocking for the
* number of milliseconds specified in the timeout field.
* </p>
*
* @param messageId the acceptable message id
* @param timeout the timeout setting in milliseconds
*
* @return the next available message
*
* @throws MessageStoreEOFException if the message store is closed
* @throws MessageNotAvailableException if the message is not available
* @throws InterruptedException if the thread is interrupted
*
* @since 0.2.0
*/
public synchronized SshMessage peekMessage(int messageId, int timeout)
throws MessageStoreEOFException, MessageNotAvailableException,
InterruptedException {
singleIdFilter[0] = messageId;
return peekMessage(singleIdFilter, timeout);
}
/**
* <p>
* Register a message implementation with the store.
* </p>
*
* @param messageId the id of the message
* @param implementor the class of the implementation
*
* @since 0.2.0
*/
public void registerMessage(int messageId, Class implementor) {
Integer id = new Integer(messageId);
register.put(id, implementor);
}
/**
* <p>
* Returns an Object array (Integers) of the registered message ids.
* </p>
*
* @return the registered message id array
*
* @since 0.2.0
*/
public Object[] getRegisteredMessageIds() {
return register.keySet().toArray();
}
/**
* <p>
* Create a formed message from raw message data.
* </p>
*
* @param msgdata the raw message data
*
* @return the formed message
*
* @throws MessageNotRegisteredException if the message is not a registered
* message
* @throws InvalidMessageException if the message is invalid
*
* @since 0.2.0
*/
public SshMessage createMessage(byte[] msgdata)
throws MessageNotRegisteredException, InvalidMessageException {
Integer messageId = SshMessage.getMessageId(msgdata);
if (!isRegisteredMessage(messageId)) {
throw new MessageNotRegisteredException(messageId);
}
Class cls = (Class) register.get(SshMessage.getMessageId(msgdata));
try {
SshMessage msg = (SshMessage) cls.newInstance();
msg.fromByteArray(new ByteArrayReader(msgdata));
return msg;
} catch (IllegalAccessException iae) {
throw new InvalidMessageException(
"Illegal access for implementation class " + cls.getName());
} catch (InstantiationException ie) {
throw new InvalidMessageException("Instantiation failed for class " +
cls.getName());
}
}
}