knowrob::TokenStream Class Reference

#include <TokenStream.h>

Inheritance diagram for knowrob::TokenStream:

Classes
class	Channel

Public Member Functions
	TokenStream ()
virtual	~TokenStream ()
	TokenStream (const TokenStream &)=delete
virtual void	close ()
bool	isOpened () const
	TokenStream ()
virtual	~TokenStream ()
	TokenStream (const TokenStream &)=delete
virtual void	close ()
bool	isOpened () const

Protected Member Functions
virtual void	push (Channel &channel, const TokenPtr &tok)
virtual void	push (const TokenPtr &tok)=0
virtual void	push (Channel &channel, const TokenPtr &tok)
virtual void	push (const TokenPtr &tok)=0

Protected Attributes
std::list< std::shared_ptr< Channel > >	channels_
std::atomic< bool >	isOpened_
std::mutex	channel_mutex_

Detailed Description

A stream of query results. The only way to write to a stream is by creating a channel.

Definition at line 22 of file TokenStream.h.

Constructor & Destructor Documentation

TokenStream() [1/4]

TokenStream::TokenStream

(

)

Definition at line 17 of file TokenStream.cpp.

        : isOpened_(true) {}

~TokenStream() [1/2]

TokenStream::~TokenStream ( )

virtual

Definition at line 20 of file TokenStream.cpp.

                          {
    close();
}

TokenStream() [2/4]

knowrob::TokenStream::TokenStream ( const TokenStream &  )

delete

Cannot be copy-assigned.

TokenStream() [3/4]

knowrob::TokenStream::TokenStream

(

)

~TokenStream() [2/2]

virtual knowrob::TokenStream::~TokenStream ( )

virtual

TokenStream() [4/4]

knowrob::TokenStream::TokenStream ( const TokenStream &  )

delete

Cannot be copy-assigned.

Member Function Documentation

close() [1/2]

void TokenStream::close ( )

virtual

Close the stream. This will push an EOS message, and all future attempts to push a non EOS message will cause a warning. Once closed, a stream cannot be opened again. Note that a stream auto-closes once it has received EOS messages from all of its input channels.

Reimplemented in knowrob::QueryStage::Pusher, knowrob::QueryStage, knowrob::QueryStage::Pusher, and knowrob::QueryStage.

Definition at line 24 of file TokenStream.cpp.

                        {
    std::list<std::shared_ptr<Channel>> channels;
    {
        std::lock_guard<std::mutex> lock(channel_mutex_);
        // make a copy of the channels list to prevent that the channels list is modified
        // while closing the channels
        channels = channels_;
    }
    // allow the channels to generate EOS messages for clean shutdown
    for (auto &channel: channels) {
        channel->close();
    }
    {
        // Finally mark the stream as closed
        std::lock_guard<std::mutex> lock(channel_mutex_);
        channels_.clear();
        isOpened_ = false;
    }
}

close() [2/2]

virtual void knowrob::TokenStream::close ( )

virtual

Close the stream. This will push an EOS message, and all future attempts to push a non EOS message will cause a warning. Once closed, a stream cannot be opened again. Note that a stream auto-closes once it has received EOS messages from all of its input channels.

Reimplemented in knowrob::QueryStage::Pusher, knowrob::QueryStage, knowrob::QueryStage::Pusher, and knowrob::QueryStage.

isOpened() [1/2]

bool TokenStream::isOpened

(

)

const

Returns

true if opened.

Definition at line 44 of file TokenStream.cpp.

                                 {
    return isOpened_;
}

isOpened() [2/2]

bool knowrob::TokenStream::isOpened

(

)

const

Returns

true if opened.

push() [1/4]

void TokenStream::push ( Channel &  channel, const TokenPtr &  tok  )

protectedvirtual

Reimplemented in knowrob::ConjunctiveBroadcaster, and knowrob::ConjunctiveBroadcaster.

Definition at line 48 of file TokenStream.cpp.

                                                            {
    if (tok->indicatesEndOfEvaluation()) {
        bool doPushMsg = false;
        {
            // prevent channels from being created or closed while processing EOS message
            std::lock_guard<std::mutex> lock(channel_mutex_);
            if (isOpened()) {
                if (channel.hasValidIterator()) {
                    // close this stream if no channels are left
                    channels_.erase(channel.iterator_);
                    channel.invalidateIterator();
                    doPushMsg = channels_.empty();
                    isOpened_ = !doPushMsg;
                } else {
                    KB_WARN("ignoring attempt to write to a channel with a singular iterator.");
                }
            }
        }
        // send EOS on this stream if no channels are left
        if (doPushMsg) {
            push(tok);
        }
    } else if (!isOpened()) {
        KB_WARN("ignoring attempt to write to a closed stream.");
    } else {
        push(tok);
    }
}

push() [2/4]

virtual void knowrob::TokenStream::push ( Channel &  channel, const TokenPtr &  tok  )

protectedvirtual

Reimplemented in knowrob::ConjunctiveBroadcaster, and knowrob::ConjunctiveBroadcaster.

push() [3/4]

virtual void knowrob::TokenStream::push ( const TokenPtr &  tok )

protectedpure virtual

Implemented in knowrob::TokenQueue, knowrob::TokenBuffer, knowrob::TokenBroadcaster, knowrob::RedundantAnswerFilter, knowrob::QueryStage, knowrob::QueryStage::Pusher, knowrob::AnswerTransformer, knowrob::TokenQueue, knowrob::TokenBuffer, knowrob::TokenBroadcaster, knowrob::RedundantAnswerFilter, knowrob::QueryStage, knowrob::QueryStage::Pusher, knowrob::AnswerTransformer, knowrob::DisjunctiveBroadcaster, and knowrob::DisjunctiveBroadcaster.

push() [4/4]

virtual void knowrob::TokenStream::push ( const TokenPtr &  tok )

protectedpure virtual

Implemented in knowrob::TokenQueue, knowrob::TokenBuffer, knowrob::TokenBroadcaster, knowrob::RedundantAnswerFilter, knowrob::QueryStage, knowrob::QueryStage::Pusher, knowrob::AnswerTransformer, knowrob::TokenQueue, knowrob::TokenBuffer, knowrob::TokenBroadcaster, knowrob::RedundantAnswerFilter, knowrob::QueryStage, knowrob::QueryStage::Pusher, knowrob::AnswerTransformer, knowrob::DisjunctiveBroadcaster, and knowrob::DisjunctiveBroadcaster.

Member Data Documentation

channel_mutex_

std::mutex knowrob::TokenStream::channel_mutex_

protected

Definition at line 120 of file TokenStream.h.

channels_

std::list< std::shared_ptr< Channel > > knowrob::TokenStream::channels_

protected

Definition at line 118 of file TokenStream.h.

isOpened_

std::atomic< bool > knowrob::TokenStream::isOpened_

protected

Definition at line 119 of file TokenStream.h.

---

The documentation for this class was generated from the following files:

• build/_CPack_Packages/Linux/DEB/knowrob-2.1.0-Linux/usr/include/knowrob/queries/TokenStream.h
• src/queries/TokenStream.cpp