JP2005309891A - Document sharing system and its terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To share documents with terminals located outside of a firewall, while reducing network load. <P>SOLUTION: A document sharing system 10 includes a server and a plurality of terminals connected to the server via a firewall. The server has a list of shared documents retained by each terminal, and a request management means for managing acquisition requests from the terminals. Each of the terminals includes a request confirmation means for making the server repeatedly confirm if there is a request from another terminal to acquire one's own documents; a document sending means for sending the one's own documents to the server when there is the request; a document request means for sending to the sever a request to acquire the documents retained by the other terminals; and a document re-requesting means for repeating the sending of re-requests for the documents to the server until the documents are obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a document sharing system that includes a server and a plurality of terminals connected to the server via a firewall, and that shares a document held by each terminal, and the terminal.

  Conventionally, there is a demand for sharing a document among a plurality of terminals. Peer-to-peer is known as one method for sharing documents between terminals. In this method, each terminal is directly connected to exchange documents. As another method, a center system in which a repository (such as a data server) is provided on the Internet and a document to be shared in the repository is registered can be considered.

  As one of such document sharing systems, Patent Document 1 discloses an information synchronization system that uses polling to synchronize documents shared by a plurality of terminals. This is synchronized by referring to the server whether or not the document has been updated by polling when referring to a document held in another terminal. In order to reduce the number of times of polling, a response from the server for polling is held until the document is updated in another terminal or until a predetermined time elapses. As a result, the number of polling operations can be reduced, and consequently, the load on the network can be reduced.

JP 2002-33787 A

  Here, when each terminal is connected via the Internet, it is difficult to exchange documents on a peer-to-peer basis. That is, in the case of connection via the Internet, it is necessary to provide a firewall in order to restrict unauthorized access from the outside, but if a firewall is provided, peer-to-peer document exchange is also restricted.

  Further, in the center method in which a repository is provided on the Internet, it is necessary to transmit document entity data to a server each time registration is performed, resulting in a high communication load. The repository capacity must also be increased.

  Therefore, an object of the present invention is to provide a document sharing system and a terminal capable of sharing a document with a terminal located outside a firewall while reducing a network load.

  A document sharing system according to the present invention includes a server and a plurality of terminals connected to the server via a firewall, and the plurality of terminals share a document held by each terminal. A list notification unit for notifying each terminal of a shared document list that is a list of documents to be shared held by each terminal, and a request management unit for managing an acquisition request from each terminal for a document included in the shared document list; Each terminal can confirm the acquisition request for the self-document by request confirmation means for repeatedly confirming to the server whether there is an acquisition request from another terminal for the self-document that is a document held by the terminal. A document sending means for sending the self-document to the server, a document requesting means for sending an acquisition request for a document held by another terminal to the server, and a request. After transmission of the acquisition request by the signal means, and having a a document re-requesting means to repeat the transmission of the re-request for the document to the server until the document can be acquired.

  In a preferred aspect, each terminal has list request means for transmitting a shared document list acquisition request to the server, and the list notification means receives the shared list in response to the shared document list acquisition request from each terminal. Send to. It is desirable that the list request unit repeatedly transmits a shared document list acquisition request to the server. The request management unit writes the presence / absence of an acquisition request for a document included in the shared list in the shared document list, and the request confirmation unit confirms the acquisition request for the self document by confirming the shared document list acquired by the list request unit. It is desirable. Immediately after the shared document list is updated, it is desirable to shorten the repetition interval of the shared document list acquisition request by the list request unit.

  In another preferred aspect, the server includes polling management means for managing an interval between repeated transmissions performed by each terminal. In another preferred aspect, the communication mode from each terminal to the server is a communication mode in which the server returns a response to the request from the terminal. In another preferred aspect, each terminal is a digital multi-function peripheral having a plurality of functions including at least a communication function and an image forming function.

  Another terminal of the document sharing system according to the present invention is a terminal of a document sharing system that is connected to a server and shares a document with another terminal, and an acquisition request from another terminal for a self document that is a document held by the terminal. Request confirmation means for repeatedly confirming the presence or absence of the server, and when the request confirmation means confirms the acquisition request for the self-document, the document transmission means for transmitting the self-document to the server and the acquisition for the document held by another terminal A document requesting unit that transmits a request to the server, and a document rerequesting unit that repeats transmission of a rerequest requesting the document to the server until the document can be acquired after the acquisition request is transmitted by the request transmitting unit. Features.

  In a preferred aspect, the terminal has list request means for transmitting a shared document list acquisition request, which is a list of documents to be shared, held in each terminal to the server and acquiring the shared document list. In another preferred aspect, the list request means repeatedly transmits a shared document list acquisition request to the server. In another preferred aspect, the server writes in the shared list whether or not there is an acquisition request for a document included in the shared list, and the request confirmation unit confirms the shared document list acquired by the list request unit. Confirm the acquisition request for the self-document. In another preferred aspect, immediately after the shared document list is updated, the repetition interval of the shared document list acquisition request by the list requesting unit is shortened.

  Here, the document is not limited to data in which a sentence is recorded, but refers to generalized information such as image data and program data.

  According to the present invention, it is possible to share a document with a terminal located outside the firewall while reducing the network load.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an overall configuration diagram of a document sharing system 10 according to an embodiment of the present invention.

  The document sharing system 10 includes a server 12 and a plurality of terminals 14 connected to the server 12 via a firewall 18. The terminal 14 corresponds to, for example, a digital multi-function peripheral (hereinafter referred to as “MFP 14a”) having a document spool unit, a personal computer (hereinafter referred to as PC 14b), or the like. Each terminal 14 is arranged in the local area network 16. The local area network 16 is connected to the Internet 20 via a firewall 18 to prevent unauthorized access from the outside. That is, the server 12 and each terminal 14 are connected via the firewall 18. Here, the firewall 18 can pass only a predetermined communication from the outside, for example, a response to a request in HTML communication.

  Therefore, the communication from the server 12 to the terminal 14 can only respond to the request from each terminal 14. In addition, since the terminals 14 arranged in different local area networks 16 have a firewall 18 therebetween, direct communication cannot be performed. In the present embodiment, document sharing is realized between terminals 14 arranged in different local area networks 16.

  Here, the mechanism of document sharing will be briefly described. The server 12 manages the document information held in each terminal 14 as a shared document list. Each terminal 14 requests this shared document list from the server 12, and the server 12 transmits the shared document list to each terminal 14 as a response. Each terminal 14 can know what documents are held in other terminals 14 by reading the shared document list. The request for the shared document list is repeated at a predetermined polling interval.

  When it is desired to acquire a document held in another terminal 14 or another document, the acquisition request is transmitted to the server 12. When the server 12 receives the acquisition request, the server 12 writes that fact in the shared document list. The terminal 14 acquires the requested document if it is in the server 12. If there is no such document, the acquisition request is polled until the requested document is uploaded to the server 12.

  When the terminal 14 holding the document reads the shared document list and knows that there is an acquisition request from another terminal 14 for the document, the terminal 14 transmits the document to the server 12. Then, the terminal 14 polling the acquisition request can acquire the document uploaded to the server 12.

  The above is a simple document sharing mechanism. Hereinafter, the document sharing system 10 will be described in detail. First, the server 12 will be described with reference to FIG. FIG. 2 is a block diagram illustrating a functional configuration of the server 12. Similarly to the normal WWW server 12, the server 12 includes a network I / F 30, an OS 28, and a WWW server function 26 capable of communication using HTML or HTMLLS. Further, as functions for realizing document sharing, a list management unit 22 that manages document information held in each terminal 14, a document spool unit 24 that temporarily holds documents transmitted from each terminal 14, and Have

  The list management unit 22 further includes a polling frequency timer 32, a list creation unit 34, a polling interval management unit 38, a shared document list 36, and the like. The polling frequency timer 32 is a timer for measuring a polling interval from each terminal 14. The list creation unit 34 creates a shared document list 36 based on document information and self-document information held by each terminal 14 transmitted from the terminal 14. The polling interval management unit 38 controls the polling interval from the terminal 14 according to the polling frequency and communication status from each terminal 14. Specifically, the control of the polling interval can be realized by writing a desired polling interval in the shared document list 36.

  The shared document list 36 will be described with reference to FIG. The shared document list 36 is a list of documents held by each terminal 14 and records information of each document and a polling interval. The information of each document includes a document ID for identifying the document, a storage location of the document, a document name, and a request count indicating whether or not there is an acquisition request for the document. This request count is incremented whenever there is an acquisition request for the document from the terminal 14, and is decremented each time the document requested by each terminal 14 is acquired. That is, when the request count is 1 or more, there is currently an acquisition request for the document. If the request count is 0, it means that there is no terminal 14 that currently needs the document.

  Next, the configuration of each terminal 14 will be described with reference to FIGS. FIG. 4 is a block diagram showing a functional configuration of the MFP 14a as an example of the terminal 14, and FIG. 5 is a partial detailed view thereof. The MFP 14 a is a digital multi-function peripheral that includes a printer unit 42, a scanner unit 40, a FAX unit 44, and the like. The MFP 14a further performs communication with a document spool unit 56 that stores documents shared with other terminals 14, a communication control unit 54 that controls communication with the server 12, a polling timer 52 that is referred to by the communication control unit 54, and communication. Network I / F 46 and a user interface (hereinafter referred to as “U / I 48”).

  The document spool unit 56 stores a document to be shared with other terminals 14. The document stored here includes a document read from the PC or the like through a network, a document read by the scanner unit 40, print data created by the printer unit 42, and the like. The user can select which of the documents held in the document spool unit 56 is to be shared with other terminals 14 via the U / I 48. The polling timer 52 is a timer used for list acquisition polling and document re-request polling, which will be described later.

  The communication control unit 54 controls communication for document sharing, and includes a list acquisition unit 60, a self document providing unit 62, and another document acquisition unit 64 (see FIG. 5). The list acquisition unit 60 further includes a self document information transmission unit 68 and a list request unit 66. The self-document information transmission unit 68 transmits the document held in the document spool unit 56, that is, the self-document information to the server 12. The information of the self document includes the document ID of the self document, the document name, the file type, the document storage location, and the like. Upon receiving the transmission of the information of the self document, the server 12 returns a communication result status (OK or NG) to the terminal 14 as a response. The transmission of the self-document information is basically performed when a new document is added to the document spool unit 56.

  An example of a message exchanged between the self-document information transmitting unit 68 and the server 12 is shown in FIG. In FIG. 6, the upper side is a message (T → S) transmitted from the self-document information transmission unit 68 (terminal 14) to the server 12, and the lower side is returned from the server 12 to the self-document information transmission unit 68 (terminal 14). Response (S → T). In the message from the terminal 14, a flag indicating that the self-document information is transmitted and the self-document information itself are recorded following the communication header. Further, in the response from the server 12, a communication result status (OK or NG) is recorded following the communication header.

  The list request unit 66 performs list request polling to the server 12. In the list request polling, a list request message for requesting the shared document list 36 is repeatedly transmitted to the server 12. The server 12 transmits the shared document list 36 to the terminal 14 as a response to the list request message transmitted from the list request unit 66 (terminal 14). If the terminal 14 receives the shared document list 36, the terminal 14 holds it. This list request polling is performed at a polling interval recorded in the shared document list 36. That is, the polling interval calculated by the polling interval management unit 38 of the server 12 is performed.

  An example of a message exchanged between the list request unit 66 (terminal 14) and the server 12 is shown in FIG. A list request message is transmitted from the list request unit 66. The response message from the server 12 follows the communication header and polling interval, followed by information on each shared document and its request count.

  Next, the self document providing unit 62 will be described. The self-document providing unit 62 includes a request confirmation unit 70 and a document transmission unit 72. The request confirmation unit 70 confirms whether or not there is an acquisition request for the self-document from another terminal 14, and this is done by reading the shared document list 36 acquired from the server 12. That is, out of the documents included in the shared document list 36, when the request count of the self document is 0, it can be determined that there is no acquisition request from another terminal 14 for the self document. When the request count is 1 or more, it is determined that there is an acquisition request from another terminal 14 and notifies the document transmission unit 72 to that effect. This request confirmation is performed each time the list request unit 66 receives the shared document list 36 from the server 12. In other words, the request confirmation is repeatedly performed at almost the same interval as the polling interval of list request polling.

  The document transmission unit 72 transmits the self-document to the server 12 when there is an acquisition request from another terminal 14 for the self-document. The server 12 that has received the transmission of the self-document returns the status of the communication result as a response. The messages exchanged between the document transmission unit 72 (terminal 14) and the server 12 are shown in FIG. The message from the terminal 14 to the server 12 includes self-document entity data.

  Next, the other document acquisition unit 64 will be described. The other document acquisition unit 64 includes a document request unit 74, a re-request unit 76, and a deletion request unit 78. The document request unit 74 transmits an acquisition request message to the server 12 when it is desired to acquire another document that is a document held in another terminal 14. Upon receiving this acquisition request message, the server 12 increments the request count of the other document in the shared document list 36 held by the server 12. Then, it is confirmed whether the other document is in the document spool unit 24 of the server 12. If there is, the other document is returned to the terminal 14 as a response. If the other document does not exist in the document spool unit 24, NG is returned as the status of the communication result. The messages exchanged between the document request unit 74 (terminal 14) and the server 12 are shown in FIG. In FIG. 9, the portion indicated by a broken line in the response message from the server 12, that is, the actual data portion of the other document is added only when the other document is in the document spool unit 24.

  The re-requesting unit 76 performs document re-request polling to the server 12 after the acquisition request message is transmitted by the document requesting unit 74. In the document re-request polling, a re-request message is repeatedly transmitted until the requested other document is transmitted from the server 12. The server 12 returns an NG status if the other document does not exist in the document spool unit 24, and returns entity data of the other document as a response if it exists. A message exchanged between the re-requesting unit 76 (terminal 14) and the server 12 is shown in FIG. In FIG. 10, the portion indicated by a broken line in the response message from the server 12, that is, the actual data portion of the other document is added only when the other document is in the document spool unit 24.

  When the other document can be acquired from the server, the deletion request unit 78 transmits a delete request message for the other document to the server 12. Upon receiving the deletion request message, the server 12 deletes the other document held in the document spool unit 24 and returns a response to the terminal. FIG. 11 shows messages exchanged at this time.

  The flow of document sharing in the document sharing system 10 including the server 12 and the terminal 14 will be described with reference to FIGS. FIG. 12 is a flowchart showing the flow of processing in the server 12, and FIG. 13 is a flowchart showing the flow of processing in the terminal 14.

  First, the server 12 initializes a polling frequency timer as an initialization process, and sets a polling interval to a default value (SS10). When the shared document list request message is received from the terminal 14, the shared document list held as a response is transmitted to the terminal 14, and the process returns to the beginning (SS22).

  If the transmission of the self-document information is received from the terminal 14, a response of the communication result is returned as the response. Also, a polling interval is set as necessary, the held shared document list is updated, and the process returns to the beginning (SS24 to SS28).

  When an acquisition request message for another document is received from the terminal 14, the request count for the document in the held shared document list is incremented. Further, it is determined whether or not the document exists in the document spool, and if there is, the document is transmitted to the terminal 14 as a response to the acquisition request message. If the document is not in the document spool, NG is returned to the terminal 14 as the status of the communication result. In either case, the process returns to the first process (SS30 to SS36).

  Furthermore, when a re-request message for another document is received, it is determined again whether the document exists in the document spool, and if there is, the document is transmitted to the terminal 14; Return to 14. Then, the process returns to the first process (SS32 to SS36).

  Further, when a deletion request message is received from the terminal 14, the request count of the document is decremented and then the document held in the document spool is deleted. Then, the process returns to the first process (SS38 to SS42).

  When receiving the self-document from the terminal 14, the self-document is stored in the document spool unit 24, and the response is transmitted to the terminal 14 (SS44 to SS46).

  Next, the process flow of the terminal 14 will be described with reference to FIG. The terminal 14 transmits a request message for the shared document list 36 according to a preset polling interval (TS10). If the shared document list 36 is received as a response to this message, it is held in the terminal 14 (TS12). The U / I reads this shared document list 36 and updates the display of sharable documents.

  The polling interval is set based on the polling interval stored in the received shared document list 36. Further, the received shared document list 36 is read to check whether there is an acquisition request from another terminal 14 for the self document (TS16). That is, it is confirmed whether the request count of the self document is 1 or more. When the request count of the self document is 1 or more, the document is transmitted to the server 12 (TS22).

  When a new document is added as a shared document, information on the self document is transmitted to the server 12 as self document information (TS18).

  If acquisition of another document held in another terminal 14 is instructed by the user, an acquisition request message for the other document is transmitted to the server 12 (TS20, TS26). If the other document is transmitted from the server 12, a deletion message of the document is transmitted to the server 12 (TS28 to TS32). On the other hand, if the other document is not transmitted from the server 12, a re-request message is transmitted to the server 12 again after a predetermined polling interval has elapsed (TS34). Then, polling of the re-request message is repeated until the other document is transmitted as a response.

  Next, a specific example of document sharing will be described with reference to FIG. FIG. 14 is a sequence diagram showing a flow when the document D1 and the document D2 are shared between the terminal 1 and the terminal 2.

  In the specific example of FIG. 14, the terminal 1 has a document D1, and the terminal 2 has a document D2. First, the terminal 1 transmits the self-document information of the document D1 and the terminal 2 of the document D2 to the server. The server updates the shared document list based on the transmitted self-document information. At this time, in the shared document list, the request counts of the document D1 and the document D2 are both 0.

  When the list request message is transmitted from the terminal 1 and the terminal 2, the server transmits the shared document list to the terminal as a response. Although the terminal 1 and the terminal 2 are provided with a firewall, the transmission of the shared document list is a response to a request from the terminal and can pass through the firewall. Each terminal can know the document information held by another terminal located outside the firewall by reading the shared document list.

  Each terminal reads the shared document list and presents information on documents that can be shared to the user. The user appropriately selects a document to be acquired from the presented documents and gives an instruction to acquire the document.

  Here, a case where the user of the terminal 1 gives an instruction to acquire the document D2 will be described. Since there is a firewall between the terminal 1 and the terminal 2, the document D2 cannot be directly requested from the terminal 1 to the terminal 2. Therefore, the terminal 1 transmits an acquisition request message for the document D2 to the server. Upon receiving this acquisition request, the server increments the request count of the document D2 in the shared document list and sets the value to 1. Also, it is confirmed whether or not there is a document D2 in the document spool.

  At this time, since the document D2 is not transmitted from the terminal 2, there is no document D2 in the document spool. Therefore, the server returns an NG status as a response to the acquisition request message from the terminal 1. The terminal 1 that has received the NG status transmits a re-request message for the document D2 to the server after a predetermined polling interval has elapsed. The server that has received this re-request message checks again whether or not the document D2 exists in the document spool, and if not, returns the NG status to the terminal 1. The terminal 1 repeats this re-request until the document D2 can be acquired.

  On the other hand, when a predetermined polling interval elapses from the previous list request, the terminal 2 transmits a list request message to the server again. Upon receiving this, the server transmits the shared document list to the terminal 2. The terminal 2 reads the shared document list transmitted from the server, and confirms the request count value for the document D2 held by itself. Here, in the shared document list transmitted from the server, the request count of the document D2 is “1”. Since the request count is 1 or more, the terminal 2 can determine that there is an acquisition request for the document D2 from another terminal. If it is determined that there is an acquisition request, the terminal 2 transmits the document D2 to the server. When receiving the document D2, the server temporarily stores it in the document spool unit.

  After the document D2 is stored in the document spool unit, when a re-request message for the document D2 is transmitted from the terminal 1, the server transmits the document D2 stored in the document spool unit to the terminal 1. Since the transmission of the document D2 from the server to the terminal 1 is also a response to the request from the terminal 1, it can pass through the firewall of the terminal 1.

  The terminal 1 that has received the document D2 transmits a deletion request for the document D2 to the server. Receiving this, the server decrements the request count of the document D2 in the shared document list, and further deletes the document D2 stored in the document spool unit.

  In this way, since the document D2 is exchanged using the server as a relay, the document D2 can be shared between terminals connected via the firewall 18. At this time, all communication from the server to the terminal is a response to the request from the terminal, so that communication can be performed through the firewall of the terminal. Further, since the document entity data is transmitted only when there is a request from another terminal, the load on the network can be reduced. Furthermore, the capacity of the server can be reduced.

  As described above, according to the present embodiment, it is possible to share a document with a terminal outside the firewall. Further, since the actual document data is not transmitted until an acquisition request is received from another terminal, the network load can be reduced.

  In the above description, whether or not there is an acquisition request from another terminal for the self document is confirmed by reading the shared document list, but the server may be directly inquired about the presence or absence of the acquisition request. That is, polling for request confirmation may be performed separately from list request polling for acquiring the shared document list.

  Next, another embodiment will be described. The basic configuration of the document sharing system 10 according to another embodiment is almost the same as that of the above-described embodiment, and will be described with reference to FIG. One of the features of this embodiment is the control of the list request polling interval.

  In this embodiment, the list request polling interval is managed by the polling interval management unit 38 of the server 12 writing the polling interval in the shared document list 36 as in the above-described embodiment. Each terminal performs list request polling at the polling interval written in the shared document list 36.

  Here, since the shared document list 36 is appropriately updated by the server 12, if the polling interval is lengthened, the updated contents cannot be quickly passed to each terminal 14, causing various problems. Conversely, if the polling interval is shortened, the update content can be immediately transmitted to each terminal, while the server load and network load increase.

  Therefore, in the present embodiment, immediately after a new shared document is added, in other words, immediately after the self-document information is transmitted from the terminal 14, the polling interval is shortened and polling is performed after a predetermined time has elapsed since the addition of the shared document. Increase the interval.

  This is due to the following reason. When a document is added to the document spool unit 56 of each terminal 14, a plurality of documents are often added continuously. In particular, when the terminal 14 is an MFP, a large number of documents read by the scanning unit, print data created at the time of printing, and the like are often added continuously. Therefore, immediately after a new shared document is added (immediately after the self-document information is transmitted from the terminal), it is highly likely that new shared documents will be added continuously thereafter.

  Therefore, immediately after the self-document information is transmitted from the terminal, the polling interval is shortened so that the update of the shared document list 36 can be quickly transmitted to each terminal. On the other hand, if a predetermined time elapses after the self-document information is transmitted, the polling interval is lengthened in order to reduce the network load.

  As described above, in the present embodiment, immediately after adding a shared document, in other words, the polling interval is shortened only when there is a high possibility that the shared document list 36 will continue to be updated, and otherwise the polling interval is lengthened. As a result, network load can be reduced while enabling rapid information transmission.

  In this embodiment, the polling interval is changed depending on whether or not the shared document is added. However, for example, the polling interval may be changed according to other factors such as a time zone and a communication load.

1 is an overall configuration diagram of a document sharing system according to an embodiment of the present invention. It is a block diagram which shows the function structure of a server. It is a figure which shows an example of a shared document list. 2 is a block diagram illustrating a functional configuration of an MFP that is an example of a terminal. FIG. FIG. 5 is a partial detail view of FIG. 4. It is a figure which shows an example of the message exchanged with a terminal and a server. It is a figure which shows an example of the message exchanged with a terminal and a server. It is a figure which shows an example of the message exchanged with a terminal and a server. It is a figure which shows an example of the message exchanged with a terminal and a server. It is a figure which shows an example of the message exchanged with a terminal and a server. It is a figure which shows an example of the message exchanged with a terminal and a server. It is a flowchart which shows the flow of a process of a server. It is a flowchart which shows the flow of a process of a terminal. FIG. 10 is a sequence diagram illustrating a specific example of document sharing.

Explanation of symbols

  10 document sharing system, 12 server, 14 terminal, 18 firewall, 22 list management unit, 24 document spool unit, 34 list creation unit, 36 shared document list, 38 polling interval management unit, 54 communication control unit, 56 document spool unit, 60 List acquisition unit, 62 Self document providing unit, 64 Other document acquisition unit.

Claims (13)

A document sharing system comprising a server and a plurality of terminals connected to the server via a firewall, wherein the documents held by each terminal are shared by the plurality of terminals,
The server
List notification means for notifying each terminal of a shared document list that is a list of documents to be shared held by each terminal;
Request management means for managing acquisition requests from each terminal for documents included in the shared document list;
Have
Each terminal
A request confirmation means for repeatedly confirming to the server whether or not there is an acquisition request from another terminal for the self-document which is a document held by the self;
A document sending means for sending the self-document to the server when the request confirmation means confirms the acquisition request for the self-document;
Document request means for sending an acquisition request for a document held by another terminal to the server;
A document re-requesting unit that repeats transmission of a re-request for requesting the document from the server until the document can be acquired after transmission of the acquisition request by the request transmitting unit;
A document sharing system comprising: The document sharing system according to claim 1,
Each terminal has list request means for transmitting a shared document list acquisition request to the server,
The list notifying unit transmits a shared list to the terminal in response to a request for acquiring the shared document list from each terminal. The document sharing system according to claim 2,
The list requesting means repeatedly transmits a shared document list acquisition request to a server. The document sharing system according to claim 3,
The request management means writes in the shared document list whether or not there is an acquisition request for a document included in the shared list,
The request confirmation unit confirms the acquisition request for the self-document by confirming the shared document list acquired by the list request unit. The document sharing system according to claim 3 or 4,
Immediately after the shared document list is updated, the document sharing system is characterized in that the repetition interval of the shared document list acquisition request by the list request unit is shortened. The document sharing system according to any one of claims 1 to 5,
The server has polling management means for managing the interval of repeated transmissions performed by each terminal. The document sharing system according to any one of claims 1 to 6,
A document sharing system, wherein a communication form from each terminal to the server is a communication form in which the server returns a response to a request from the terminal. The document sharing system according to any one of claims 1 to 7,
A document sharing system, wherein each terminal is a digital multi-function peripheral having a plurality of functions including at least a communication function and an image forming function. A document sharing system terminal connected to a server and sharing a document with another terminal,
A request confirmation means for repeatedly confirming to the server whether or not there is an acquisition request from another terminal for the self-document which is a document held by the self;
A document sending means for sending the self-document to the server when the request confirmation means confirms the acquisition request for the self-document;
Document request means for sending an acquisition request for a document held by another terminal to the server;
A document re-requesting unit that repeats transmission of a re-request for requesting the document from the server until the document can be acquired after transmission of the acquisition request by the request transmitting unit;
A document sharing system terminal characterized by comprising: The document sharing system according to claim 9,
The terminal has a list request unit for transmitting a shared document list acquisition request, which is a list of documents to be shared held in each terminal, to the server and acquiring the shared document list. Terminal. A terminal of the document sharing system according to claim 10,
The list requesting unit repeatedly transmits a shared document list acquisition request to a server, and is a terminal of a document sharing system. A terminal of the document sharing system according to claim 11,
In the shared list, whether or not there is an acquisition request for a document included in the shared list is written by the server,
The request confirmation unit confirms an acquisition request for the self-document by confirming the shared document list acquired by the list request unit. A document sharing system terminal according to claim 11 or 12,
Immediately after the shared document list is updated, the terminal of the document sharing system is characterized in that the repetition interval of the shared document list acquisition request by the list request unit is shortened.

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