gnu.java.nio

Class KqueueSelectorImpl


public class KqueueSelectorImpl
extends AbstractSelector

A Selector implementation that uses the kqueue event notification facility.

Constructor Summary

KqueueSelectorImpl(SelectorProvider provider)
Initializes the slector.

Method Summary

boolean
equals(Object o)
Determine whether this Object is semantically equal to another Object.
protected void
implCloseSelector()
Closes the channel.
Set<E>
keys()
Returns this selector's key set.
static boolean
kqueue_supported()
Tell if kqueue-based selectors are supported on this system.
protected SelectionKey
register(AbstractSelectableChannel channel, int interestOps, Object attachment)
Registers a channel for the selection process.
int
select()
Selects a set of keys whose corresponding channels are ready for I/O operations.
int
select(long timeout)
Selects a set of keys whose corresponding channels are ready for I/O operations.
int
selectNow()
Selects a set of keys whose corresponding channels are ready for I/O operations.
Set<E>
selectedKeys()
Returns this selector's selected-key set.
String
toString()
Convert this Object to a human-readable String.
Selector
wakeup()
Causes the first selection operation that has not yet returned to return immediately.

Methods inherited from class java.nio.channels.spi.AbstractSelector

begin, cancelledKeys, close, deregister, end, implCloseSelector, isOpen, provider, register

Methods inherited from class java.nio.channels.Selector

close, isOpen, keys, open, provider, select, select, selectNow, selectedKeys, wakeup

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

KqueueSelectorImpl

public KqueueSelectorImpl(SelectorProvider provider)
            throws IOException
Initializes the slector.
Parameters:
provider - the provider that created this selector

Method Details

equals

public boolean equals(Object o)
Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

  • It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
  • It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
  • It must be reflexive. a.equals(a) must always be true.
  • It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
  • a.equals(null) must be false.
  • It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.

Overrides:
equals in interface Object
Parameters:
Returns:
whether this Object is semantically equal to another

implCloseSelector

protected void implCloseSelector()
            throws IOException
Closes the channel.
Overrides:
implCloseSelector in interface AbstractSelector
Throws:
IOException - if an error occurs

keys

public Set<E> keys()
Returns this selector's key set.
Overrides:
keys in interface Selector
Throws:
ClosedSelectorException - If this selector is closed.

kqueue_supported

public static boolean kqueue_supported()
Tell if kqueue-based selectors are supported on this system.
Returns:
True if this system has kqueue support, and support for it was compiled in to Classpath.

register

protected SelectionKey register(AbstractSelectableChannel channel,
                                int interestOps,
                                Object attachment)
Registers a channel for the selection process.
Overrides:
register in interface AbstractSelector
Parameters:
Returns:
the registered selection key

select

public int select()
            throws IOException
Selects a set of keys whose corresponding channels are ready for I/O operations.
Overrides:
select in interface Selector
Throws:
ClosedSelectorException - If this selector is closed.
IOException - If an error occurs

select

public int select(long timeout)
            throws IOException
Selects a set of keys whose corresponding channels are ready for I/O operations.
Overrides:
select in interface Selector
Parameters:
timeout - The timeout to use.
Throws:
ClosedSelectorException - If this selector is closed.
IllegalArgumentException - If the timeout value is negative.
IOException - If an error occurs

selectNow

public int selectNow()
            throws IOException
Selects a set of keys whose corresponding channels are ready for I/O operations.
Overrides:
selectNow in interface Selector
Throws:
ClosedSelectorException - If this selector is closed.
IOException - If an error occurs

selectedKeys

public Set<E> selectedKeys()
Returns this selector's selected-key set.
Overrides:
selectedKeys in interface Selector
Throws:
ClosedSelectorException - If this selector is closed.

toString

public String toString()
Convert this Object to a human-readable String. There are no limits placed on how long this String should be or what it should contain. We suggest you make it as intuitive as possible to be able to place it into System.out.println() and such.

It is typical, but not required, to ensure that this method never completes abruptly with a RuntimeException.

This method will be called when performing string concatenation with this object. If the result is null, string concatenation will instead use "null".

The default implementation returns getClass().getName() + "@" + Integer.toHexString(hashCode()).

Overrides:
toString in interface Object
Returns:
the String representing this Object, which may be null

wakeup

public Selector wakeup()
Causes the first selection operation that has not yet returned to return immediately.
Overrides:
wakeup in interface Selector

KqueueSelectorImpl.java -- Selector for systems with kqueue event notification. Copyright (C) 2006 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.