diff options
Diffstat (limited to 'libjava/gnu/java/nio/SelectorImpl.java')
| -rw-r--r-- | libjava/gnu/java/nio/SelectorImpl.java | 394 |
1 files changed, 0 insertions, 394 deletions
diff --git a/libjava/gnu/java/nio/SelectorImpl.java b/libjava/gnu/java/nio/SelectorImpl.java deleted file mode 100644 index dcafedeb8bb..00000000000 --- a/libjava/gnu/java/nio/SelectorImpl.java +++ /dev/null @@ -1,394 +0,0 @@ -/* SelectorImpl.java -- - Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. - -This file is part of GNU Classpath. - -GNU Classpath 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, or (at your option) -any later version. - -GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the -Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301 USA. - -Linking this library statically or dynamically with other modules is -making a combined work based on this library. Thus, the terms and -conditions of the GNU General Public License cover the whole -combination. - -As a special exception, the copyright holders of this library give you -permission to link this library with independent modules to produce an -executable, regardless of the license terms of these independent -modules, and to copy and distribute the resulting executable under -terms of your choice, provided that you also meet, for each linked -independent module, the terms and conditions of the license of that -module. An independent module is a module which is not derived from -or based on this library. If you modify this library, you may extend -this exception to your version of the library, but you are not -obligated to do so. If you do not wish to do so, delete this -exception statement from your version. */ - - -package gnu.java.nio; - -import java.io.IOException; -import java.nio.channels.ClosedSelectorException; -import java.nio.channels.SelectableChannel; -import java.nio.channels.SelectionKey; -import java.nio.channels.Selector; -import java.nio.channels.spi.AbstractSelectableChannel; -import java.nio.channels.spi.AbstractSelector; -import java.nio.channels.spi.SelectorProvider; -import java.util.Collections; -import java.util.HashSet; -import java.util.Iterator; -import java.util.Set; - -public class SelectorImpl extends AbstractSelector -{ - private Set keys; - private Set selected; - - /** - * A dummy object whose monitor regulates access to both our - * selectThread and unhandledWakeup fields. - */ - private Object selectThreadMutex = new Object (); - - /** - * Any thread that's currently blocked in a select operation. - */ - private Thread selectThread; - - /** - * Indicates whether we have an unhandled wakeup call. This can - * be due to either wakeup() triggering a thread interruption while - * a thread was blocked in a select operation (in which case we need - * to reset this thread's interrupt status after interrupting the - * select), or else that no thread was on a select operation at the - * time that wakeup() was called, in which case the following select() - * operation should return immediately with nothing selected. - */ - private boolean unhandledWakeup; - - public SelectorImpl (SelectorProvider provider) - { - super (provider); - - keys = new HashSet (); - selected = new HashSet (); - } - - protected void finalize() throws Throwable - { - close(); - } - - protected final void implCloseSelector() - throws IOException - { - // Cancel any pending select operation. - wakeup(); - - synchronized (keys) - { - synchronized (selected) - { - synchronized (cancelledKeys ()) - { - // FIXME: Release resources here. - } - } - } - } - - public final Set keys() - { - if (!isOpen()) - throw new ClosedSelectorException(); - - return Collections.unmodifiableSet (keys); - } - - public final int selectNow() - throws IOException - { - // FIXME: We're simulating an immediate select - // via a select with a timeout of one millisecond. - return select (1); - } - - public final int select() - throws IOException - { - return select (0); - } - - private final int[] getFDsAsArray (int ops) - { - int[] result; - int counter = 0; - Iterator it = keys.iterator (); - - // Count the number of file descriptors needed - while (it.hasNext ()) - { - SelectionKeyImpl key = (SelectionKeyImpl) it.next (); - - if ((key.interestOps () & ops) != 0) - { - counter++; - } - } - - result = new int[counter]; - - counter = 0; - it = keys.iterator (); - - // Fill the array with the file descriptors - while (it.hasNext ()) - { - SelectionKeyImpl key = (SelectionKeyImpl) it.next (); - - if ((key.interestOps () & ops) != 0) - { - result[counter] = key.getNativeFD(); - counter++; - } - } - - return result; - } - - public synchronized int select (long timeout) - throws IOException - { - if (!isOpen()) - throw new ClosedSelectorException(); - - synchronized (keys) - { - synchronized (selected) - { - deregisterCancelledKeys(); - - // Set only keys with the needed interest ops into the arrays. - int[] read = getFDsAsArray (SelectionKey.OP_READ - | SelectionKey.OP_ACCEPT); - int[] write = getFDsAsArray (SelectionKey.OP_WRITE - | SelectionKey.OP_CONNECT); - - // FIXME: We dont need to check this yet - int[] except = new int [0]; - - // Test to see if we've got an unhandled wakeup call, - // in which case we return immediately. Otherwise, - // remember our current thread and jump into the select. - // The monitor for dummy object selectThreadMutex regulates - // access to these fields. - - // FIXME: Not sure from the spec at what point we should - // return "immediately". Is it here or immediately upon - // entry to this function? - - // NOTE: There's a possibility of another thread calling - // wakeup() immediately after our thread releases - // selectThreadMutex's monitor here, in which case we'll - // do the select anyway. Since calls to wakeup() and select() - // among different threads happen in non-deterministic order, - // I don't think this is an issue. - synchronized (selectThreadMutex) - { - if (unhandledWakeup) - { - unhandledWakeup = false; - return 0; - } - else - { - selectThread = Thread.currentThread (); - } - } - - // Call the native select() on all file descriptors. - int result = 0; - try - { - begin(); - result = VMSelector.select (read, write, except, timeout); - } - finally - { - end(); - } - - // If our unhandled wakeup flag is set at this point, - // reset our thread's interrupt flag because we were - // awakened by wakeup() instead of an external thread - // interruption. - // - // NOTE: If we were blocked in a select() and one thread - // called Thread.interrupt() on the blocked thread followed - // by another thread calling Selector.wakeup(), then race - // conditions could make it so that the thread's interrupt - // flag is reset even though the Thread.interrupt() call - // "was there first". I don't think we need to care about - // this scenario. - synchronized (selectThreadMutex) - { - if (unhandledWakeup) - { - unhandledWakeup = false; - Thread.interrupted (); - } - selectThread = null; - } - - Iterator it = keys.iterator (); - - while (it.hasNext ()) - { - int ops = 0; - SelectionKeyImpl key = (SelectionKeyImpl) it.next (); - - // If key is already selected retrieve old ready ops. - if (selected.contains (key)) - { - ops = key.readyOps (); - } - - // Set new ready read/accept ops - for (int i = 0; i < read.length; i++) - { - if (key.getNativeFD() == read[i]) - { - if (key.channel () instanceof ServerSocketChannelImpl) - { - ops = ops | SelectionKey.OP_ACCEPT; - } - else - { - ops = ops | SelectionKey.OP_READ; - } - } - } - - // Set new ready write ops - for (int i = 0; i < write.length; i++) - { - if (key.getNativeFD() == write[i]) - { - ops = ops | SelectionKey.OP_WRITE; - - // if (key.channel ().isConnected ()) - // { - // ops = ops | SelectionKey.OP_WRITE; - // } - // else - // { - // ops = ops | SelectionKey.OP_CONNECT; - // } - } - } - - // FIXME: We dont handle exceptional file descriptors yet. - - // If key is not yet selected add it. - if (!selected.contains (key)) - { - selected.add (key); - } - - // Set new ready ops - key.readyOps (key.interestOps () & ops); - } - deregisterCancelledKeys(); - - return result; - } - } - } - - public final Set selectedKeys() - { - if (!isOpen()) - throw new ClosedSelectorException(); - - return selected; - } - - public final Selector wakeup() - { - // IMPLEMENTATION NOTE: Whereas the specification says that - // thread interruption should trigger a call to wakeup, we - // do the reverse under the covers: wakeup triggers a thread - // interrupt followed by a subsequent reset of the thread's - // interrupt status within select(). - - // First, acquire the monitor of the object regulating - // access to our selectThread and unhandledWakeup fields. - synchronized (selectThreadMutex) - { - unhandledWakeup = true; - - // Interrupt any thread which is currently blocked in - // a select operation. - if (selectThread != null) - selectThread.interrupt (); - } - - return this; - } - - private final void deregisterCancelledKeys() - { - Set ckeys = cancelledKeys (); - synchronized (ckeys) - { - Iterator it = ckeys.iterator(); - - while (it.hasNext ()) - { - keys.remove ((SelectionKeyImpl) it.next ()); - it.remove (); - } - } - } - - protected SelectionKey register (SelectableChannel ch, int ops, Object att) - { - return register ((AbstractSelectableChannel) ch, ops, att); - } - - protected final SelectionKey register (AbstractSelectableChannel ch, int ops, - Object att) - { - SelectionKeyImpl result; - - if (ch instanceof SocketChannelImpl) - result = new SocketChannelSelectionKey (ch, this); - else if (ch instanceof DatagramChannelImpl) - result = new DatagramChannelSelectionKey (ch, this); - else if (ch instanceof ServerSocketChannelImpl) - result = new ServerSocketChannelSelectionKey (ch, this); - else - throw new InternalError ("No known channel type"); - - synchronized (keys) - { - keys.add (result); - } - - result.interestOps (ops); - result.attach (att); - return result; - } -} |
