Content acquiring device, method, and system using valid terms to keep a cache up-to-date

• US 6,976,057 B2
• Filed: 12/27/2000
• Issued: 12/13/2005
• Est. Priority Date: 12/27/1999
• Status: Expired due to Fees

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Yoshiasa, Masahiro
• Primary Examiner(s): Alam, Hosain
• Assistant Examiner(s): LAZARO, DAVID R
• Application Number:
  US09/749,186
• Publication Number:
  US 20010025305A1
• Time in Patent Office: 1,812 Days
• Field of Search: 709/203, 709/216, 709/217, 709/219, 709/227, 707/200
• US Class Current: 709/216
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching

Abstract

To provide a content acquiring device, a content acquiring method, a content server and a content acquiring system which can minimize an acquisition request for content data and can acquire content data having a current version as much as possible. By using a validity term previously held by the content acquiring device or a validity term of the content added during content acquisition, it is previously decided in the device whether the content are to be updated or not, thereby transmitting an acquisition request to be an access to a content server for storing content data requested to be acquired through a network.

Claims

1. A content acquiring device comprising:

cache means for temporarily storing received content;

acquisition request accepting means for accepting an acquisition request for content;

cache deciding means for deciding whether or not the content requested by the acquisition request is stored in the cache means;

validity expiration setting means for setting a validity expiration as an update expiration of the content based on a validity term of the content, when it is decided by the cache deciding means that the content is stored in the cache means;

acquisition request transmitting means for transmitting the acquisition request for the content, when the content is past the validity expiration set by the validity expiration setting means;

content receiving means for receiving content based on the acquisition request transmitted from the acquisition request transmitting means,

wherein if a control section determines that the content is received normally by the content receiving means, the control section updates with the content received the cache means; and

further comprising validity term holding means for holding a previously held validity term, and validity term addition deciding means for deciding whether or not the validity term is associated with the content, when it is decided by the cache deciding means that the content is stored in the cache means, the validity expiration setting means serving to set the validity expiration based on the previously held validity term held by the validity term holding means when it is decided by the validity term addition deciding means that the validity term was not associated,

wherein when the content requested to be acquired from the content server does not exist or cannot be found, the control section deletes the corresponding content stored in the cache section.

2. A method of acquiring content comprising the steps of:

accepting an acquisition request for content;

deciding whether or not the content requested by the acquisition request accepted at the acquisition request accepting step is stored in a cache for temporarily storing received content;

setting a validity expiration as an update expiration of the content based on a validity term added to the content when it is decided at the deciding step that the content is stored in the cache;

transmitting the acquisition request for the content when the content has passed the validity expiration set at the validity expiration setting step;

receiving content corresponding to the acquisition request transmitted at the acquisition request transmitting step,

wherein if a control section determines that the content is received normally by the content receiving means, the control section updates with the content received the cache; and

further comprising the step of deciding whether or not the validity term is associated with the content when it is decided at the cache deciding step that the content is stored in the cache, the validity expiration setting step serving to set the validity expiration based on a previously held validity term when it is decided at the validity term addition deciding step that the validity term is not associated,

wherein when the content requested to be acquired from the content server does not exist or cannot be found, the control section deletes the corresponding content stored in the cache.

3. A content server comprising:

content storing means for previously storing content;

acquisition request receiving means for receiving an acquisition request transmitted when the content has passed a validity expiration serving as an update expiration of the content stored in a cache, which validity expiration is set based on a validity term of the content; and

content transmitting means for fetching the content requested by the acquisition request received by the acquisition request receiving means from the content storing means and for transmitting the content to a destination of the acquisition request,

wherein if a control section determines that the content is received normally by the content receiving means, the control section updates with the content received the cache,

wherein the validity expiration is set based on a previously held validity term in destination of the acquisition request when the validity term is not associated with the content stored in the cache,

wherein when the content requested to be acquired from the content server does not exist or cannot be found, the control section deletes the corresponding content stored in the cache.

4. A content acquiring system comprising:

a content acquiring device for transmitting via a network an acquisition request for content that is an acquisition request object prestored when the content has passed a validity expiration serving as an update expiration of the content set based on a validity term of the content, and for receiving content corresponding thereto; and

a content server for reading content corresponding to an acquisition request transmitted from the content acquiring device from content in various fields which are prestored, and for transmitting via the network the content corresponding to the acquisition request to the content acquiring device,

wherein if a control section determines that the content is received normally by the content receiving means, the control section updates with the content received a cache,

wherein the validity expiration is set based on a predetermined validity term previously held, when a validity term is not added to the content that is the acquisition request object,

wherein when the content requested to be acquired from the content server does not exist or cannot be found, the control section deletes the corresponding content stored in the cache.

5. A content acquiring system comprising:

a content acquiring device including cache means for temporarily storing received content, acquisition request accepting means for accepting an acquisition request for content, cache deciding means for deciding whether or not the content requested by the acquisition request is stored in the cache means, validity expiration setting means for setting a validity expiration as an update expiration of the content based on a validity term added to the content when it is decided by the cache deciding means that the content is stored in the cache means, acquisition request transmitting means for transmitting the acquisition request for the content when the content have passed the validity expiration set by the validity expiration setting means, and content receiving means for receiving content based on the acquisition request transmitted from the acquisition request transmitting means;

a content server including content storing means for previously storing content, acquisition request receiving means for receiving an acquisition request transmitted from the acquisition request transmitting means, and content transmitting means for fetching the content requested by the acquisition request received by the acquisition request receiving means from the content storing means, and for transmitting the content to the content acquiring device,

wherein if a control section determines that the content is received normally by the content receiving means, the control section updates with the content received the cache means; and

further comprising validity term holding means for previously holding a validity term, and validity term addition deciding means for deciding whether or not the validity term is associated with the content, when it is decided by the cache deciding means that the content is stored in the cache means, the validity expiration setting means serving to set the validity expiration based on a held validity term of the validity term holding means when it is decided by the validity term addition deciding means that the validity term is not associated,

wherein when the content requested to be acquired from the content server does not exist or cannot be found, the control section deletes the corresponding content stored in the cache means.