ZPoller

java.lang.Object
- org.zeromq.ZPoller

All Implemented Interfaces:: java.io.Closeable, java.lang.AutoCloseable

public class ZPoller
extends java.lang.Object
implements java.io.Closeable

Rewritten poller for ØMQ. Polls selectable channels and sockets for specified events.

This poller can be used in two ways:

the traditional one, where you make something like

 
            ZPoller poller = ...
            poller.register(socket, ZPoller.POLLIN);
            poller.register(channel, ZPoller.OUT);

            int events = poller.poll(-1L);

            if (poller.isReadable(socket)) {
                ...
            }
            if (poller.writable(channel)) {
                ...
            }

the event-driven way

 

            ZPoller poller = ...

            poller.setGlobalHandler(...)
            ZPoller.EventsHandler handler = ...

            // The events method of the handler will be called
            poller.register(channel, handler, ZPoller.IN);

            // The events method of the global handler will be called
            poller.register(socket, ZPoller.POLLOUT);

            poller.poll(-1L);
            // handlers have been called

The motivations of this rewriting are:

the bare poller used ZMQ.poll(Selector, PollItem[], int, long). This method did not allow to choose the selector used for polling, relying on a ThreadLocal, which is dangerous.
the bare poller use algorithms tailored for languages with manual allocation. No need here as Java allows more flexibility. TODO There still may be a small penalty cost.

It’s thread safe, but newly registered items will only be handled at the next poll iteration, so if poller.poll(-1L) is used, adding items will have no effect. The situation is the same with the global handler

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`ZPoller.ComposeEventsHandler`
`private class`	`ZPoller.CompositePollItem`
`static interface`	`ZPoller.EventsHandler`
`static interface`	`ZPoller.ItemCreator`
`static interface`	`ZPoller.ItemHolder`
`static class`	`ZPoller.SimpleCreator`
`static class`	`ZPoller.ZPollItem`

Field Summary

Fields
Modifier and Type	Field and Description
`private ZPoller.ItemCreator`	`creator`
`private java.lang.ThreadLocal<ZPoller.EventsHandler>`	`currentGlobalHandler`
`static int`	`ERR`
`private java.util.concurrent.atomic.AtomicReference<ZPoller.EventsHandler>`	`globalHandler`
`static int`	`IN`
`private java.util.Map<java.lang.Object,ZPoller.CompositePollItem>`	`items`
`static int`	`OUT`
`static int`	`POLLERR`
`static int`	`POLLIN`
`static int`	`POLLOUT`
`static int`	`READABLE`
`private java.nio.channels.Selector`	`selector`
`static int`	`WRITABLE`

Constructor Summary

Constructors
Modifier	Constructor and Description
	`ZPoller(java.nio.channels.Selector selector)` Creates a new poller with a given selector for operational polling.
	`ZPoller(ZContext context)` Creates a new poller attached to a given context that will provide selector for operational polling.
`private`	`ZPoller(ZPoller.ItemCreator creator, java.nio.channels.Selector selector)` Creates a new poller.
	`ZPoller(ZPoller.ItemCreator creator, ZContext context)` Creates a new poller attached to a given context that will provide selector for operational polling.
	`ZPoller(ZPoller.ItemCreator creator, ZPoller poller)` Creates a new poller based on the current one.
	`ZPoller(ZPoller poller)` Creates a new poller based on the current one.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected boolean`	`add(java.lang.Object socketOrChannel, ZPoller.ItemHolder holder)`
`void`	`close()` Destroys the poller.
`private java.lang.Object`	`computeSocketOrChannel(ZPoller.ItemHolder holder)`
`protected ZPoller.ItemHolder`	`create(java.nio.channels.SelectableChannel channel, ZPoller.EventsHandler handler, int events)`
`protected ZPoller.ItemHolder`	`create(ZMQ.Socket socket, ZPoller.EventsHandler handler, int events)`
`protected java.util.Set<ZPoller.ItemHolder>`	`createContainer(int size)` Deprecated. useless
`void`	`destroy()` Destroys the poller without exception.
`boolean`	`dispatch()` dispatches all the polled events to their respective handlers
`protected boolean`	`dispatch(java.util.Collection<? extends ZPoller.ItemHolder> allDispatched)` Dispatches the polled events.
`protected boolean`	`dispatch(java.util.Collection<? extends ZPoller.ItemHolder> all, int size)` Deprecated. Uses `dispatch(Collection)` instead, as size is unused
`private boolean`	`dispatch(java.util.Set<ZPoller.CompositePollItem> allPolled)`
`boolean`	`error(java.lang.Object socketOrChannel)`
`boolean`	`error(java.nio.channels.SelectableChannel channel)`
`boolean`	`error(ZMQ.Socket socket)`
`protected PollItem`	`filter(java.lang.Object socketOrChannel, int events)`
`ZPoller.EventsHandler`	`getGlobalHandler()` Returns the global events handler for all registered sockets.
`boolean`	`isError(java.nio.channels.SelectableChannel channel)` Tells if a channel is in error from this poller.
`boolean`	`isError(ZMQ.Socket socket)` Tells if a socket is in error from this poller.
`boolean`	`isReadable(java.nio.channels.SelectableChannel channel)` Tells if a channel is readable from this poller.
`boolean`	`isReadable(ZMQ.Socket socket)` Tells if a socket is readable from this poller.
`boolean`	`isWritable(java.nio.channels.SelectableChannel channel)` Tells if a channel is writable from this poller.
`boolean`	`isWritable(ZMQ.Socket socket)` Tells if a socket is writable from this poller.
`protected java.util.Collection<ZPoller.ItemHolder>`	`items()` Return a copy of all the items of this poller.
`protected java.lang.Iterable<ZPoller.ItemHolder>`	`items(java.lang.Object socketOrChannel)`
`int`	`poll(long timeout)` Issue a poll call, using the specified timeout value.
`protected int`	`poll(long timeout, boolean dispatchEvents)` Issue a poll call, using the specified timeout value.
`protected int`	`poll(java.nio.channels.Selector selector, long tout, java.util.Collection<PollItem> items)`
`boolean`	`pollerr(java.nio.channels.SelectableChannel channel)`
`boolean`	`pollerr(ZMQ.Socket socket)`
`boolean`	`pollin(java.nio.channels.SelectableChannel channel)`
`boolean`	`pollin(ZMQ.Socket socket)`
`boolean`	`pollout(java.nio.channels.SelectableChannel channel)`
`boolean`	`pollout(ZMQ.Socket socket)`
`boolean`	`readable(java.lang.Object socketOrChannel)`
`boolean`	`readable(java.nio.channels.SelectableChannel channel)`
`boolean`	`readable(ZMQ.Socket socket)`
`boolean`	`register(java.nio.channels.SelectableChannel channel, BiFunction<java.nio.channels.SelectableChannel,java.lang.Integer,java.lang.Boolean> handler, int events)` Registers a SelectableChannel for polling on specified events.
`boolean`	`register(java.nio.channels.SelectableChannel channel, int events)` Registers a SelectableChannel for polling on specified events.
`boolean`	`register(java.nio.channels.SelectableChannel channel, ZPoller.EventsHandler handler)` Registers a SelectableChannel for polling on all events.
`boolean`	`register(java.nio.channels.SelectableChannel channel, ZPoller.EventsHandler handler, int events)` Registers a SelectableChannel for polling on specified events.
`boolean`	`register(ZMQ.Socket socket, BiFunction<ZMQ.Socket,java.lang.Integer,java.lang.Boolean> handler, int events)` Register a Socket for polling on specified events.
`boolean`	`register(ZMQ.Socket socket, int events)` Register a Socket for polling on specified events, using the global `ZPoller.EventsHandler`.
`boolean`	`register(ZMQ.Socket socket, ZPoller.EventsHandler handler)` Register a Socket for polling on all events.
`boolean`	`register(ZMQ.Socket socket, ZPoller.EventsHandler handler, int events)` Register a Socket for polling on specified events.
`boolean`	`register(ZPoller.ItemHolder item)` Register an ItemHolder for polling on specified events.
`int`	`registered()`
`void`	`setGlobalHandler(ZPoller.EventsHandler globalHandler)` Sets the global events handler for all registered sockets.
`private boolean`	`subDispatch(java.util.Collection<? extends ZPoller.ItemHolder> allDispatched)`
`boolean`	`unregister(java.lang.Object socketOrChannel)` Unregister a Socket or SelectableChannel for polling on the specified events.
`boolean`	`writable(java.lang.Object socketOrChannel)`
`boolean`	`writable(java.nio.channels.SelectableChannel channel)`
`boolean`	`writable(ZMQ.Socket socket)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - POLLIN
```
public static final int POLLIN
```
    See Also:
    
    Constant Field Values
  - POLLOUT
```
public static final int POLLOUT
```
    See Also:
    
    Constant Field Values
  - POLLERR
```
public static final int POLLERR
```
    See Also:
    
    Constant Field Values
  - IN
```
public static final int IN
```
    See Also:
    
    Constant Field Values
  - OUT
```
public static final int OUT
```
    See Also:
    
    Constant Field Values
  - ERR
```
public static final int ERR
```
    See Also:
    
    Constant Field Values
  - READABLE
```
public static final int READABLE
```
    See Also:
    
    Constant Field Values
  - WRITABLE
```
public static final int WRITABLE
```
    See Also:
    
    Constant Field Values
  - selector
```
private final java.nio.channels.Selector selector
```
  - creator
```
private final ZPoller.ItemCreator creator
```
  - items
```
private final java.util.Map<java.lang.Object,ZPoller.CompositePollItem> items
```
  - globalHandler
```
private final java.util.concurrent.atomic.AtomicReference<ZPoller.EventsHandler> globalHandler
```
  - currentGlobalHandler
```
private final java.lang.ThreadLocal<ZPoller.EventsHandler> currentGlobalHandler
```
- Constructor Detail
  - ZPoller
```
public ZPoller(ZPoller poller)
```
    Creates a new poller based on the current one. This will be a shadow poller, sharing the same selector and items creator. The global events handler will not be shared.
    
    Parameters:
    
    poller - the main poller.
  - ZPoller
```
public ZPoller(java.nio.channels.Selector selector)
```
    Creates a new poller with a given selector for operational polling.
    
    Parameters:
    
    selector - the selector to use for polling.
  - ZPoller
```
public ZPoller(ZContext context)
```
    Creates a new poller attached to a given context that will provide selector for operational polling.
    
    Parameters:
    
    context - the context that will provide the selector to use for polling.
  - ZPoller
```
public ZPoller(ZPoller.ItemCreator creator,
               ZPoller poller)
```
    Creates a new poller based on the current one. This will be a shadow poller, sharing the same selector. The global events handler will not be shared.
    
    Parameters:
    
    creator - the items creator
    
    poller - the main poller.
  - ZPoller
```
public ZPoller(ZPoller.ItemCreator creator,
               ZContext context)
```
    Creates a new poller attached to a given context that will provide selector for operational polling.
    
    Parameters:
    
    creator - the items creator
    
    context - the context that will provide the selector to use for polling.
  - ZPoller
```
private ZPoller(ZPoller.ItemCreator creator,
                java.nio.channels.Selector selector)
```
    Creates a new poller.
    
    Parameters:
    
    creator - the items creator
    
    selector - the selector to use for polling.
- Method Detail
  - create
```
protected ZPoller.ItemHolder create(ZMQ.Socket socket,
                                    ZPoller.EventsHandler handler,
                                    int events)
```
  - create
```
protected ZPoller.ItemHolder create(java.nio.channels.SelectableChannel channel,
                                    ZPoller.EventsHandler handler,
                                    int events)
```
  - setGlobalHandler
```
public void setGlobalHandler(ZPoller.EventsHandler globalHandler)
```
    Sets the global events handler for all registered sockets.
    
    Parameters:
    
    globalHandler - the events handler to set
  - getGlobalHandler
```
public ZPoller.EventsHandler getGlobalHandler()
```
    Returns the global events handler for all registered sockets.
    
    Returns:
    
    the global events handler for all registered sockets.
  - register
```
public final boolean register(ZMQ.Socket socket,
                              BiFunction<ZMQ.Socket,java.lang.Integer,java.lang.Boolean> handler,
                              int events)
```
    Register a Socket for polling on specified events.
    
    Parameters:
    
    socket - the registering socket.
    
    handler - the events handler for this socket
    
    events - the events to listen to, as a mask composed by ORing POLLIN, POLLOUT and POLLERR.
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(ZMQ.Socket socket,
                              ZPoller.EventsHandler handler,
                              int events)
```
    Register a Socket for polling on specified events.
    
    Parameters:
    
    socket - the registering socket.
    
    handler - the events handler for this socket
    
    events - the events to listen to, as a mask composed by ORing POLLIN, POLLOUT and POLLERR.
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(ZMQ.Socket socket,
                              ZPoller.EventsHandler handler)
```
    Register a Socket for polling on all events.
    
    Parameters:
    
    socket - the registering socket.
    
    handler - the events handler for this socket
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(ZMQ.Socket socket,
                              int events)
```
    Register a Socket for polling on specified events, using the global ZPoller.EventsHandler.
    
    Parameters:
    
    socket - the registering socket.
    
    events - the events to listen to, as a mask composed by ORing POLLIN, POLLOUT and POLLERR.
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(java.nio.channels.SelectableChannel channel,
                              BiFunction<java.nio.channels.SelectableChannel,java.lang.Integer,java.lang.Boolean> handler,
                              int events)
```
    Registers a SelectableChannel for polling on specified events.
    
    Parameters:
    
    channel - the registering channel.
    
    handler - the events handler for this channel
    
    events - the events to listen to, as a mask composed by ORing POLLIN, POLLOUT and POLLERR.
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(java.nio.channels.SelectableChannel channel,
                              ZPoller.EventsHandler handler,
                              int events)
```
    Registers a SelectableChannel for polling on specified events.
    
    Parameters:
    
    channel - the registering channel.
    
    handler - the events handler for this channel
    
    events - the events to listen to, as a mask composed by ORing POLLIN, POLLOUT and POLLERR.
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(java.nio.channels.SelectableChannel channel,
                              ZPoller.EventsHandler handler)
```
    Registers a SelectableChannel for polling on all events.
    
    Parameters:
    
    channel - the registering channel.
    
    handler - the events handler for this channel
    
    Returns:
    
    true if registered, otherwise false
  - register
```
public final boolean register(java.nio.channels.SelectableChannel channel,
                              int events)
```
    Registers a SelectableChannel for polling on specified events.
    
    Parameters:
    
    channel - the registering channel.
    
    events - the events to listen to, as a mask composed by ORing POLLIN, POLLOUT and POLLERR.
    
    Returns:
    
    true if registered, otherwise false
  - registered
```
public int registered()
```
    Returns:
    
    the number of registered object, mixing Sockets and SelectableChannels
  - register
```
public final boolean register(ZPoller.ItemHolder item)
```
    Register an ItemHolder for polling on specified events.
    
    Parameters:
    
    item - the registering item.
    
    Returns:
    
    true if registered, otherwise false
  - unregister
```
public final boolean unregister(java.lang.Object socketOrChannel)
```
    Unregister a Socket or SelectableChannel for polling on the specified events.
    
    Parameters:
    
    socketOrChannel - the Socket or SelectableChannel to be unregistered
    
    Returns:
    
    true if unregistered, otherwise false TODO would it be useful to unregister only for specific events ?
  - poll
```
public int poll(long timeout)
```
    Issue a poll call, using the specified timeout value.
    Since ZeroMQ 3.0, the timeout parameter is in milliseconds, but prior to this the unit was microseconds.
    If timeout is -1 and there is no object registered, it will return immediately
    
    Parameters:
    
    timeout - the timeout, as per zmq_poll (); if -1, it will block indefinitely until an event happens; if 0, it will return immediately; otherwise, it will wait for at most that many milliseconds/microseconds (see above).
    
    Returns:
    
    how many objects where signaled by poll ()
    
    See Also:
    
    "http://api.zeromq.org/3-0:zmq-poll"
  - poll
```
protected int poll(long timeout,
                   boolean dispatchEvents)
```
    Issue a poll call, using the specified timeout value.
    If timeout is -1 and there is no object registered, it will return immediately
    
    Parameters:
    
    timeout - the timeout, as per zmq_poll ();
    
    dispatchEvents - true to dispatch events using items handler and the global one.
    
    Returns:
    
    how many objects where signaled by poll ()
    
    See Also:
    
    "http://api.zeromq.org/3-0:zmq-poll"
  - poll
```
protected int poll(java.nio.channels.Selector selector,
                   long tout,
                   java.util.Collection<PollItem> items)
```
  - dispatch
```
private boolean dispatch(java.util.Set<ZPoller.CompositePollItem> allPolled)
```
  - dispatch
```
@Deprecated
protected boolean dispatch(java.util.Collection<? extends ZPoller.ItemHolder> all,
                                       int size)
```
    Deprecated. Uses dispatch(Collection) instead, as size is unused
    
    Dispatches the polled events.
    
    Parameters:
    
    all - the items used for dispatching
    
    size - Unused
    
    Returns:
    
    true if correctly dispatched, false in case of error
  - dispatch
```
protected boolean dispatch(java.util.Collection<? extends ZPoller.ItemHolder> allDispatched)
```
    Dispatches the polled events.
    
    Parameters:
    
    allDispatched - the items used for dispatching
    
    Returns:
    
    true if correctly dispatched, false in case of error
  - dispatch
```
public boolean dispatch()
```
    dispatches all the polled events to their respective handlers
    
    Returns:
    
    true if correctly dispatched, false in case of error
  - subDispatch
```
private boolean subDispatch(java.util.Collection<? extends ZPoller.ItemHolder> allDispatched)
```
  - isReadable
```
public boolean isReadable(java.nio.channels.SelectableChannel channel)
```
    Tells if a channel is readable from this poller.
    
    Parameters:
    
    channel - the channel to ask for.
    
    Returns:
    
    true if readable, otherwise false
  - readable
```
public boolean readable(java.nio.channels.SelectableChannel channel)
```
  - isReadable
```
public boolean isReadable(ZMQ.Socket socket)
```
    Tells if a socket is readable from this poller.
    
    Parameters:
    
    socket - the socket to ask for.
    
    Returns:
    
    true if readable, otherwise false
  - readable
```
public boolean readable(ZMQ.Socket socket)
```
  - readable
```
public boolean readable(java.lang.Object socketOrChannel)
```
  - pollin
```
public boolean pollin(ZMQ.Socket socket)
```
  - pollin
```
public boolean pollin(java.nio.channels.SelectableChannel channel)
```
  - isWritable
```
public boolean isWritable(java.nio.channels.SelectableChannel channel)
```
    Tells if a channel is writable from this poller.
    
    Parameters:
    
    channel - the channel to ask for.
    
    Returns:
    
    true if writable, otherwise false
  - writable
```
public boolean writable(java.nio.channels.SelectableChannel channel)
```
  - isWritable
```
public boolean isWritable(ZMQ.Socket socket)
```
    Tells if a socket is writable from this poller.
    
    Parameters:
    
    socket - the socket to ask for.
    
    Returns:
    
    true if writable, otherwise false
  - writable
```
public boolean writable(ZMQ.Socket socket)
```
  - writable
```
public boolean writable(java.lang.Object socketOrChannel)
```
  - pollout
```
public boolean pollout(ZMQ.Socket socket)
```
  - pollout
```
public boolean pollout(java.nio.channels.SelectableChannel channel)
```
  - isError
```
public boolean isError(java.nio.channels.SelectableChannel channel)
```
    Tells if a channel is in error from this poller.
    
    Parameters:
    
    channel - the channel to ask for.
    
    Returns:
    
    true if in error, otherwise false
  - error
```
public boolean error(java.nio.channels.SelectableChannel channel)
```
  - isError
```
public boolean isError(ZMQ.Socket socket)
```
    Tells if a socket is in error from this poller.
    
    Parameters:
    
    socket - the socket to ask for.
    
    Returns:
    
    true if in error, otherwise false
  - error
```
public boolean error(ZMQ.Socket socket)
```
  - error
```
public boolean error(java.lang.Object socketOrChannel)
```
  - pollerr
```
public boolean pollerr(ZMQ.Socket socket)
```
  - pollerr
```
public boolean pollerr(java.nio.channels.SelectableChannel channel)
```
  - close
```
public void close()
```
    Destroys the poller. Does actually nothing.
    
    Specified by:
    
    close in interface java.io.Closeable
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
  - destroy
```
public void destroy()
```
    Destroys the poller without exception.
  - add
```
protected boolean add(java.lang.Object socketOrChannel,
                      ZPoller.ItemHolder holder)
```
  - computeSocketOrChannel
```
private java.lang.Object computeSocketOrChannel(ZPoller.ItemHolder holder)
```
  - createContainer
```
@Deprecated
protected java.util.Set<ZPoller.ItemHolder> createContainer(int size)
```
    Deprecated. useless
    
    Return a new HashSet
    
    Parameters:
    
    size - the initial capacity of the hash table
    
    Returns:
    
    a new hash set
  - items
```
protected java.util.Collection<ZPoller.ItemHolder> items()
```
    Return a copy of all the items of this poller.
  - items
```
protected java.lang.Iterable<ZPoller.ItemHolder> items(java.lang.Object socketOrChannel)
```
  - filter
```
protected PollItem filter(java.lang.Object socketOrChannel,
                          int events)
```

Class ZPoller

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

POLLIN

POLLOUT

POLLERR

IN

OUT

ERR

READABLE

WRITABLE

selector

creator

items

globalHandler

currentGlobalHandler

Constructor Detail

ZPoller

ZPoller

ZPoller

ZPoller

ZPoller

ZPoller

Method Detail

create

create

setGlobalHandler

getGlobalHandler

register

register

register

register

register

register

register

register

registered

register

unregister

poll

poll

poll

dispatch

dispatch

dispatch

dispatch

subDispatch

isReadable

readable

isReadable

readable

readable

pollin

pollin

isWritable

writable

isWritable

writable

writable

pollout

pollout

isError

error

isError

error

error

pollerr

pollerr

close

destroy

add

computeSocketOrChannel

createContainer

items

items

filter