Patent ID: 9059997
Filing Date: 2015-06-16
Classification: H04L

Abstract:
1. A client device in a content obtainment system in which one or more server apparatuses obtain a plurality of contents stored in the client device, the client device comprising: a storage unit configured to store the plurality of contents; a content management unit configured to cause the one or more server apparatuses to obtain the stored contents; a difference information management unit configured to generate difference information as information common to the one or more server apparatuses, and provide the difference information in response to a request of each of the one or more server apparatuses, the difference information including content information about a content not obtained by all of the one or more server apparatuses from the client device from among the stored contents; an obtained content management unit configured to receive, from each of the one or more server apparatuses, obtained content information which is content information about a content obtained by the server apparatus; and a server management unit configured to store one or more server identifiers for identifying the one or more server apparatuses, wherein the difference information management unit is configured to delete, from the difference information, content information about a content obtained by all of the one or more server apparatuses, based on the received obtained content information; and, in the case where a new content is added to the contents stored in the storage unit or a content stored in the storage unit is updated or deleted, include content information about the added, updated, or deleted content in the difference information as new content information, the obtained content management unit is configured to receive, from the server apparatus, a server identifier of the server apparatus and the obtained content information, and record the received server identifier and obtained content information in association with each other, the difference information management unit is configured to delete, from the difference information, content information indicated by obtained content information associated with all server identifiers stored in the server management unit from among all obtained content information recorded by the obtained content management unit, the difference information management unit is configured to: manage a difference number indicating, by a magnitude relation thereof, time series of state change including content addition, update, or deletion, in association with content information about a content not obtained by all of the one or more server apparatuses from the client device; and, each time the state change that the new content is added to the client device or the stored content is updated or deleted occurs, increase the difference number and associate the increased difference number with the content information about the content having the state change, the obtained content management unit is configured to receive, from the server apparatus, a maximum difference number out of all difference numbers associated with the obtained content information, the server management unit is configured to manage a server management table in which the received server identifier and maximum difference number are associated with each other, and the difference information management unit is configured to select a minimum difference number out of difference numbers associated with all server identifiers stored in the server management unit, and delete, from the difference information, content information associated with a difference number equal to or less than the minimum difference number.