Abstract:
Classification of e-mails stored in a storage device of an e-mail terminal into groups by the e-mail terminal. The method includes: storing to a storage device of the e-mail terminal relations between keywords and groups, wherein each of the relations is capable of relating a single keyword with plural groups; designating one of the groups in the relations; and categorizing an e-mail that includes the keywords related to the designated group as one belonging to the designated group.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to an electronic mail (hereinafter may be referred to as e-mails or mails), a terminal for receiving/sending e-mails. This invention particularly relates to method, device and computer program for classifying or grouping e-mails.  
         [0003]     2. Description of the Related Art  
         [0004]     In order to manage data of received mails, some e-mail terminals automatically classify received mails into groups and, in accordance with user input to designate one of the groups, display a list of part of the received mails belonging to the designated group.  
         [0005]     Japanese Unexamined Patent Publication No. 2001-75891, hereinafter referred to as cited reference 1, discloses an e-mail receiver device that automatically classifies a received mail into one of groups in accordance with predetermined relation between the groups and sender&#39;s addresses.  
         [0006]     Japanese Unexamined Patent Publication No. 2002-244984, hereinafter referred to as cited reference 2, discloses an e-mail management device that previously registers relation between addresses and storage areas and stores a received mail into one of the storage areas in accordance with the relation.  
         [0007]     Japanese Unexamined Patent Publication No. 2003-242083, hereinafter referred to as cited reference 3, discloses an e-mail management device that classifies a mail in accordance with group information in its sender&#39;s address and sorts a list of received mails in accordance with the classification. In the cited reference, a mail address is composed of an account, an at mark (@) and a combination of subdomains and domains, and the group information is for example the combination of subdomains and domains, or a letter string following the at mark.  
         [0008]     Japanese Unexamined Patent Publication No. 2003-198633, hereinafter referred to as cited reference 4, discloses an e-mail server computer for handling incoming mails. The server classifies a mail into one of groups, stores the mail into a storage area for the group, and sends the mail in response to requests from clients which belong to the group. Each of the groups is for example related with a subdomain/domain of its recipient&#39;s address, a keyword in its subject, or a keyword in its message body.  
         [0009]     According to the cited references 1, 2 and 3, a single senders address is related with a single group in the relation. Since this is one-to-one relation, these techniques are unavailable for one-to-many relation.  
         [0010]     For example, it is assumed that a user U 1  of an address aaa@bbb.ccc is a friend and a business partner of another user U 2 . According to the cited references 1-3, the user has to select one of a group “business partners” or a group “friends” and relate the selected one to the address aaa@bbb.ccc When the selected group is designated to display a list of part of all mails in a storage device, the mails from the address aaa@bbb.ccc are included in the list. On the other hand, when the other group is designated, the mails from the address aaa@bbb.ccc are not included.  
         [0011]     According to the cited reference 4, a mail is classified into a group with reference to its subject or message body. If its subject or message body includes predetermined keywords related to a designated group, then the mail is classified into the designated group. Since mail addresses are not referred to classify mails, mails received from a single address can be classified into different groups. However, this classification requires predetermined keywords to classify mails.  
         [0012]     One of objects of the present invention is to provide technique for classifying e-mails into groups where a member belonging to one of the groups may belong to another one of the groups.  
       SUMMARY OF THE INVENTION  
       [0013]     This invention provides a method of classifying electronic mails or e-mails stored in a storage device of an e-mail terminal into groups by the e-mail terminal. The method includes: storing to a storage device of the e-mail terminal relations between keywords and groups, wherein each of the relations is capable of relating a single keyword with plural groups; designating one of the groups in the relations; and categorizing an e-mail that includes the keywords related to the designated group as one belonging to the designated group.  
         [0014]     The e-mail terminal is for example a desktop/laptop computer, a PDA (Personal Digital Assistant), a wireless communication terminal such as cellular phone terminal. The designation of a group may be made as user operation with input device such as keypad, keyboard and mouse, or as output from another process executed on the e-mail terminal.  
         [0015]     If an e-mail includes a header field, then at least one of the keywords may be compared to the body of the header field at the step of categorizing. Particularly, if the header field is an originator field of the e-mail, then it is preferable that the keywords include an e-mail address and the e-mail address is compared to the body of the originator field at the step of categorizing.  
         [0016]     If an e-mail includes a message body, then at least one of the keywords may be compared to words in the message body at the step of categorizing.  
         [0017]     This classification is applicable for displaying a list of part of e-mails stored in an e-mail terminal on its display device. In this case, the method includes: storing to a storage device of the e-mail terminal relations between keywords and groups, wherein each of the relations is capable of relating a single keyword with plural groups; designating one of the groups in the relations; categorizing ones of the e-mails that include the keywords related to the designated group as ones belonging to the designated group; and displaying a list of the categorized mails on a display device of the e-mail terminal.  
         [0018]     This invention further provides a terminal device for receiving electronic mails or e-mails. This terminal includes storage for storing relations between keywords and groups, wherein each of the relations is capable of relating a single keyword with plural groups; a unit for designating one of the groups in the relations; and a processor for categorizing an e-mail that includes the keywords related to the designated group as one belonging to the designated group. The unit for designating a group may be an input device such as keypad, keyboard and mouse, or may be the processor that executes another process.  
         [0019]     If an e-mail includes a header field, then the processor may compare at least one of the keywords to the body of the header field. Particularly, if the header field is an originator field of the e-mail, then it is preferable that the keywords include an e-mail address and the processor compares the e-mail address to the body of the originator field.  
         [0020]     If an e-mail includes a message body, then the processor may compare at least one of the keywords to words in the message body.  
         [0021]     It is preferable that the processor categorizes ones of the e-mails that include the keywords related to the designated group as ones belonging to the designated group and the terminal device further includes a display device for displaying a list of the categorized mails.  
         [0022]     This invention further provides a computer readable medium storing computer executable instructions operable to execute a method for classifying electronic mails or e-mails stored in a storage device of an e-mail terminal into groups by the e-mail terminal. The method includes: storing to a storage device of the e-mail terminal relations between keywords and groups, wherein each of the relations is capable of relating a single keyword with plural groups; designating one of the groups in the relations; and categorizing an e-mail that includes the keywords related to the designated group as one belonging to the designated group.  
         [0023]     According to one aspect of the present invention, an e-mail client registers classification information in which a single e-mail address may be related to plural groups. In response to designating one of the groups, the client retrieves mails received from addresses related to the designated group from a storage device for storing received mails  
         [0024]     According to another aspect of the present invention, plural group attributes may be given to a single e-mail address. Even if an address belongs to plural groups, then mails from the address are included in each one of the plural groups. Therefore, the classification of the present invention is applicable to practical human relationship.  
         [0025]     According to another aspect of the present invention, since the classification is independent from data structure of mails in a storage device, it is easy to add a new group to current groups, to remove one of current groups and to update current groups. It is not required to move sets of mail data from a storage area to another in order to classify an address from a current group to another group. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  shows a block diagram for describing a portable communication terminal as an embodiment of the present invention;  
         [0027]      FIG. 2  shows a table of group attribute information  201 ;  
         [0028]      FIG. 3  shows a table of address book information  301 ;  
         [0029]      FIG. 4  shows a table of mail data  401 ;  
         [0030]      FIG. 5  shows a relation between the address book information  301  and the mail data  401 ;  
         [0031]      FIG. 6  shows a flowchart for describing processes of displaying a list of mails with designating a group;  
         [0032]      FIG. 7  shows a flowchart for describing STEP  703  in  FIG. 6 ;  
         [0033]      FIG. 8  shows a flowchart for describing STEP  705  in  FIG. 6 ;  
         [0034]      FIG. 9A  shows an example of displayed list of mails of the mail data  401  with designating a group;  
         [0035]      FIG. 9B  shows an example of displayed list of mails of the mail data  401  with designating a group;  
         [0036]      FIG. 9C  shows an example of displayed list of mails of the mail data  401  with designating a group; and  
         [0037]      FIG. 9D  shows an example of displayed list of mails of the mail data  401  with designating a group. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0038]     Description will be made about an embodiment of the present invention. As shown in  FIG. 1 , this embodiment is a portable communication terminal  101 , which includes functions for receiving/sending e-mail, such as a cellular phone terminal and a PDA (Personal Data Assistance) with a wireless communication unit.  
         [0039]     The portable communication terminal  101  includes a processor  102 , a program storage  103 , a memory  104 , a communication portion  105 , a key event processor  106 , a keypad  107  and a display portion  108 .  
         [0040]     The processor  102  retrieves corresponding mails from the memory  104 .  
         [0041]     The memory  104  is a RAM (Random Access Memory) and includes a work area  104   a , a mail area  109 , a classification information area  110 . The processor  102  loads programs and data to the work area  104   a . The mail area  109  stores mails received through the communication portion  105 . The classification information area  110  stores information for classifying mails stored in the mail area  109 . The classification information area  110  includes a group information area  111  and an address book area  112 , The contents of the classification information area  110  and the address book area  112  will be hereinafter described,  
         [0042]     The display portion  108  includes an image displaying circuit  111  and an image display device  112 .  
         [0043]     The program storage  103  is a memory device including a computer readable recording medium for storing programs that the portable communication terminal  101  performs according to.  
         [0044]     In accordance with instructions from the processor  012 , the communication portion  105  receives/sends electronic mails or e-mails from/to other e-mail clients.  
         [0045]     The keypad  107  is an input device for receiving input operations by the user of the portable communication terminal  101 . The keypad  107  converts physical operations of fingers to signals.  
         [0046]     The key event processor  106  receives signals from the keypad  107  and translates them to specific character codes, As a result, the processor  102  receives information corresponding to the input operations.  
         [0047]     The display portion  108  displays images on its screen under control of the processor  102  in accordance with the input operations through the keypad  107 . The image displaying circuit  111  generates image signals corresponding to instructions from the processor  102 . The image display device  114  displays images corresponding to the image signals.  
         [0048]     The group information area  111  stores sets of group attribute information each of which means that if a set of group attribute information has been related to an e-mail address, then e-mails received from the e-mail address is to be classified into a group corresponding to the set of group attribute information.  
         [0049]     A set of group attribute information is composed of a group number and a group name. A group number designates a group defined in the sets of group attribute information stored in the group information area  111 . A group name shows its corresponding group to the user. The sets of group attribute information are editable by input operations through the keypad  107 .  
         [0050]     For example, as shown In  FIG. 2 , group numbers  202  and group names  203  are related to each other in group attribute information sets  201 . A group name  203  is initially set as a combination of “GROUP” and its corresponding group number  202 . The group name “GROUP 5” corresponding to the group number “05” has not been edited. On the other hand; the group names corresponding to the group numbers “01”, “02”, “03” and “04” have already been edited to change to “BUSINESS”, “ALUMNI”, “FISHING” and “DRINKING”, respectively.  
         [0051]     Turning to  FIG. 1 , the address book area  112  stores address book information including registration numbers, registrant names and e-mail addresses. Two or more e-mail addresses may be related to a single registration number and registrant name. Additionally, one or plural group numbers, which have been described with reference to  FIG. 2 , may be related to a single e-mail address and be stored In the address book area  112 .  
         [0052]     For example, as shown in  FIG. 3 , address book information  301  includes registration numbers  302 , registrant names  303 , e-mail addresses  304  and classified group numbers  305 . One or two e-mail addresses are related to each one of the registration numbers  302  and registrant names  303 . One, two or three group numbers are related to each one of the e-mail addresses  304 .  
         [0053]     The group information area  111  previously stores group numbers and then one of them is stored in the address book area  112 . With reference to Figs.  2  and  3 , group numbers “01”, “02”, “03”, “04” and “05” and corresponding group names are previously defined in the group attribute information  201 . Then, One, two or three of the group numbers “01”, “02”, “03”, “04” and “05” are related to each one of the e-mail addresses  304  as the classified group numbers  305 .  
         [0054]     A registrant name  303  is a name of a user of a corresponding e-mail address. The user may be an individual or a company. One or plural e-mail addresses may be related to each of the registrant names  303 . The processor  102  generates a new registration number  302  in response to registration of a new registrant name  304 .  
         [0055]     Turning to  FIG. 1 , the mail area  109  stores mails received through the communication portion  105  in accordance with the processor  102 .  
         [0056]     For example, the mail area  109  stores mail data  401  as shown in  FIG. 4 . The mail data  401  now includes eleven records each of which corresponds to an e-mail received from another e-mail terminal through the communication portion  105 . Each of the records includes a mail number  402 , a received time  403 , a sender&#39;s address  404 , a subject  405 , and a massage body  406 . In accordance with the programs  103   a  or input operation through the keypad  107 , the processor  102  may add a sender&#39;s address  404  to the address book information  301  if the sender&#39;s address  404  has not been registered to the address book information  301 .  
         [0057]     As described above, the mail addresses  303  are previously related to group numbers  305  in the address book information  301 , and then, a mail of the mail data  401  can be classified into groups that the sender&#39;s address  404  of the mail is related to in the address book information  301 , In the case of the group attribute information  201  shown in  FIG. 2 , the address book information  301  shown in  FIG. 3  and the mail data  401  shown in  FIG. 4 , this classification is shown as  FIG. 5 . With reference to the mail of the top record of the mail data  401 , its sender&#39;s address  404  “i-hmuro@xyz.ne.jp” is related to the group numbers “02”, “03” and “04” in the address book information  301 . Therefore, the top record can be classified into the group numbers “02”, “03” and “04”, namely the groups “ALUMNI”, “FISHING” and “DRINKING” respectively as defined in the group attribute information  201 .  
         [0058]     Turning back to  FIG. 1 , the processor  102  reads the programs  103 a stored in the program storage  103  and performs various processes in accordance with the programs  103   a.    
         [0059]     For example: the processor  102  updates the group attribute information  201  stored in the group information area  111  In accordance with input operation through the keypad  107 ; the processor  102  updates the address book information  301  stored in the address book area  112  in accordance with the input operation; and the processor  102  makes the communication portion  105  receive a mail and stores it into the mail area  109 .  
         [0060]     Further, the processor  102  performs processes for: accepting a group number through the keypad  107  for designating a group in the group attribute information  201 ; retrieving, from the mail data  401 , mails whose sender&#39;s addresses are related to the designated group; and sending signals to display the retrieved mails on the screen of the display portion  108 .  
         [0061]     Next, brief description will be made about operation of the portable communication terminal  101 . The operation is performed under control of the processor  102  running the programs  103   a.    
         [0062]     In accordance with input operation through the keypad  107 , group numbers  202  and group names  203  are stored in the group information area Ill as group attribute information  201 .  
         [0063]     With reference to the stored group attribute information  201 , classified group numbers  305  are set to each mail address  304  in the address book information  301 , which is stored in the address book area  112 .  
         [0064]     In response to receiving a mail by the communication portion  105 , the processor  102  adds the new mail to the mail data  401  stored in the mail area  109 .  
         [0065]     When the user instructs the portable communication terminal  101  to display mails without designating specific groups, the display portion  108  displays a list including all mails in the mail data  401 . Contents of the list are dependent on the size/resolution of the screen of the display portion  108 . The contents may be part of all items in the mail data  401  and, for example, may only include the sender&#39;s addresses  404  and the subjects  405 . In this case, displayed mail data items are independent from their sender&#39;s address  404  and related group numbers.  
         [0066]     On the other hand, when the user instructs the terminal  101  to display mails with designating specific groups, the display portion  108  displays for example as shown in  FIG. 2 , a list of groups that has been registered in the group attribute information  201  and displays request for selecting one or plural-groups from the list with the keypad  107  to the user.  
         [0067]     If the user designates a group number, the processor  102  retrieves mail addresses that are related to the designated group number in the address book information  301 . Next, the processor  102  retrieves, from the mail data  401 , mails whose sender&#39;s addresses  404  correspond to the retrieved mail addresses. Then, the processor  102  makes the display portion  108  display a list of the retrieved mail items. The displayed list only includes mails whose sender&#39;s addresses  404  is related to the designated group number in the address book information  301 . As a result, if the user designates a group, then mails sent from addresses classified into the designated group are displayed on the screen of the display portion  108 .  
         [0068]     Detailed description will be made about the operation of the portable communication terminal  101  with reference to  FIG. 6 . It is assumed that: the group information area  111  is storing the group attribute information  201  shown in  FIG. 2 ; the address book area  112  is storing the address book information  301  shown in  FIG. 3 ; and the mail area  109  is storing the mail data  401  shown in  FIG. 4 .  
         [0069]     In  FIG. 6 , “SelGrp” is a group number that the user of the terminal  101  inputs through the keypad  107  to select a group to display on the screen; “NumRcvM” Is a number of mails stored in the mail data  401 ; “ptrAddr” is a pointer for one of the registration numbers  302 , or zero if no corresponding one exists in the address book information  301 ; “ptrRcvM” is a pointer for one of the mail numbers  402  in the mail data  401 ; “acntRcvM” is a sender&#39;s address  404  corresponding to a current pointer “ptrRcvM”; and “getGrp” is one of the classified group numbers  305 , or zero if no corresponding one exists in the address book information  301 . In order to run the programs  103   a , the processor  102  stores and updates these variables in the work area  104   a.    
         [0070]     SelGrp is previously set with the keypad  107 . First, the processor  102  initializes prtRcvM to designate the mail number  402  “01”, namely prtRcvM=1 (STEP  701 ).  
         [0071]     Next, the processor  102  accesses to the mail area  109  to read the mail data  401 , searches for a mail of the mail number prtRcvM and acquires its sender&#39;s address  404  as acntRcvM (STEP  702 ).  
         [0072]     The processor  102  then accesses to the address book area  112  to read the address book information  301  and searches for the mail address acntRcvM from the mail addresses  304  (STEP  703 ). If the mail address acntRcvM is found, then the processor  102  sets the variable ptrAddr at the registration number  302  corresponding to the mail address acntRcvM in the address book information  304 . If the mail address acntRcvM is not registered In the address book information  304 , then the processor  102  sets ptrAddr at zero.  
         [0073]     Next, the processor  102  reads the value of ptrAddr to decide the following process (STEP  704 ). If ptrAddr≦0, then the processor  102  jumps to STEP  708  without displaying the mail of ptrRcvM on the screen of the display portion  108 , since the value of ptrAddr means that the corresponding sende&#39;s address acntRcvM is not registered in the address book information  301 , and consequently, the address acntRcvM does not belong to the group designated by SelGrp.  
         [0074]     On the other hand, if the ptrAddr&gt;0 at STEP  704 , namely the address acntRcvM has been registered in the address book information  301 , then the processor  102  performs a process for deciding whether the address acntRcvM is related to the group number SelGrp (STEP  705 ). If the address is related to the group, then the variable getGrp is set to the group number designated by SelGrp. If the address is not related to the group, then the variable getGrp is set to zero.  
         [0075]     The processor  102  selects the following step depending on the value of getGrp (STEP  706 ). If getGrp=0, the processor  102  skips over STEP  707  to STEP  708 , without displaying the mail of ptrRcvM on the screen of the display portion  108 . If getGrp&gt;0, the processor  102  instructs the display portion  108  to display the mail designated by ptrRcvM on the screen (STEP  707 ).  
         [0076]     From STEP  702  to  707 , it is decided whether a mail designated by a current value of ptrRcvM is to be displayed or not. After that, the processor  102  increments ptrRcvM (STEP  708 ) and compares the incremented ptrRcvM with a number of mails in the mail data  401 , which has previously been acquired as NumRcvM (STEP  709 ). If ptrRcvM≦NumRcvM, namely a mail designated by incremented prtRcvM exists in the mail data  401 , then the operation continues to STEP  702 . If ptrRcvM&gt;NumRcvM, namely no corresponding mail exists in the mail data  401 , then the operation is ended.  
         [0077]     As a result, each one of mails in the mail data  401  is judged whether its sender&#39;s address is related to the group designated by SelGrp in the address book information  301 , and only mails sent from addresses classified into a designated group are displayed on the display portion  108 .  
         [0078]     STEP  703  will be described with reference to  FIG. 7 . In addition to the above-mentioned variables, followings are used in  FIG. 7 . ptrAddr is a pointer for designating a registration number  302  in the address book information  301 . acntAddr is a variable for storing an mail address  304  in the address book information  301 . NumAddr is a number of mail addresses  304  stored in the address book information  301 .  
         [0079]     First, the processor  102  initializes to ptrAddr=1, which designates one of the registration numbers  302  “01” in the address book information  301  (STEP  801 ).  
         [0080]     Next, the processor  102  reads a mail address  304  related to the registration number ptrAddr=1, namely “xxxx@abc.co.jp” in the address book information  301  and sets “xxxx@abc.co.jp” to acntaddr (STEP  802 ). Then, the processor  102  compares the mail addresses stored in acntaddr and acntRcv, which has been stored at STEP  702  (STEP  802 ).  
         [0081]     If acntaddr agrees with acntRcvM, then the processor  102  proceeds to STEP  704 . If acntaddr disagrees with acntRcvM, then the processor  102  proceeds to STEP  804  (STEP  803 ).  
         [0082]     In order to compare acntRcvM with next one of the mail addresses  304 , the processor  102  adds +1 to ptraddr (STEP  804 ) and compares ptrAddr with NumAdder (STEP  805 ).  
         [0083]     If ptrAddr is smaller than or equal to NumAddr, then STEPS  802  to  805  are repeated, since there may be a mail address which agrees with acntRcvM. If ptrAddr is larger than NumAddr, namely none of the mail addresses  304  agrees with acntRcvM, then the processor  102  sets ptrAddr to NULL and proceeds to STEP  704 .  
         [0084]     STEP  705  will be described with reference to  FIG. 9 , in which: NumGrp is a number of the classified group numbers  305  in address book information  301 ; ptrGrp is a pointer for designating one of the registration numbers  302  in the address book information  301 ; and getGrp is one of the classified group numbers  304  designated by ptrgrp.  
         [0085]     Since it is confirmed that ptrAddr&gt;0 at STEP  704 , there is a mail address corresponding to acntRcvM in the address book information  301 . The processor  102  sets a number of the classified group numbers  305  related to the mail of which mail address is acntRcvM (STEP  901 ).  
         [0086]     If no group number is related to the mail address, then the processor  102  proceeds to STEP  908 . In this case, the processor  102  sets getGrp=0 and proceeds to STEP  706  (STEP  908 ).  
         [0087]     If one or more group numbers are related to the mail address, then the processor  102  proceeds to STEP  903 . In this case, the processor  102  initializes ptrGrp=1 (STEP  903 ) and sets a 1st one of the classified group numbers  305  to getGrp (STEP  904 ). Then the processor  102  compares getGrp with SelGrp, which is previously selected by the user (STEP  905 ).  
         [0088]     If getGrp agrees with SelGrp, then the processor  102  keeps the current value of getGrp and proceeds to STEP  706 . If getGrp disagrees with SelGrp, then the processor  102  increments ptrgrp (STEP  906 ) and compares ptrGrp with NumGrp (STEP  907 ).  
         [0089]     If ptrGrp is smaller than or equal to NumGrp, then the processor  102  repeats STEPS  904  to  907  in order to compare a next classified group number getGrp with the selected group number SelGrp. If ptrGrp is larger than NumGrp, then the processor  102  sets getGrp=0 and proceeds to STEP  706 . Since that means that, although one or more group numbers are related to a mail address designated by ptrAddr, the selected group number SelGrp is not related to the mail address.  
         [0090]     Example of classification by the portable communication terminal  101  will be described with reference to  FIG. 9 , Now each of the group attribute information  201 , the address book information  301  and the mail data  401  stores the values shown in  FIGS. 2, 3  and  4 , respectively. 
        (A) It is assumed that the user selects the group “BUSINESS” in the group attribute information  201  by designating the group number  202  “01” or the group name  201  “BUSINESS” through the keypad  107 . In this case, as shown in  FIG. 5 , the selected group number “01” or the selected group name “BUSINESS” is related to four mails of which mail numbers are “03”, “05”, “07” and “08”. The sender&#39;s addresses of these four mails “xxx@abc.co.jp”, “c-bhara@xxx.co.jp” and “g-fkawa@xxx.com” are related to the group “BUSINESS” in the address book information  301 . Therefore, in response to the selection of the group “BUSINESS”, the processor  102  makes the display portion  108  to display a part of the mail data  401 , as shown in  FIG. 9A .     (B) It is similarly assumed that the user selects the group “ALUMNI” in the group attribute information  201  by designating the group number  202  “02” or the group name  201  “ALUMNI” through the keypad  107 . In this case, the selected group number “02” or the selected group name “ALUMNI” is related to seven mails as shown in  FIG. 5 . The sender&#39;s addresses of these seven mails are related to the group “ALUMNI” in the address book information  301 . Therefore, in response to the selection of the group “ALUMNI”, another part of the mail data  401  is displayed on the display portion  108 , as shown in  FIG. 9B .     (C) It is assumed that the user selects the group “FISHING” in the group attribute information  201  by designating the group number  202  “03” or the group name  201  “FISHING” through the keypad  107 . In this case, the selected group number “03” is related to five mails as shown in  FIG. 5 . Therefore, in response to the selection of the group “FISHING”, another part of the mail data  401  is displayed on the display portion  108 , as shown in  FIG. 9C .     (D) It is assumed that the user selects the group “DRINKING” in the group attribute information  201  by designating the group number  202  “04” or the group name  201  “DRINKING” through the keypad  107 . In this case, the selected group number “04” is related to seven mails as shown in  FIG. 5 . Therefore, in response to the selection of the group “DRINKING”, another part of the mail data  401  is displayed on the display portion  108 , as shown in  FIG. 9D .        
 
         [0095]     It is noted that although “g-fkawa@xxx.com” and “gko-f™zzz.ne.jp” are related to a single registrant name “FKAWA GKO”, each of these addresses is independently related to classified group numbers. “g-fkawa@xxx.com” is related to the group number “01”. “gko-f@zzz.ne.jp” is related to the group numbers “02” and “04”,  
         [0096]     According to one aspect of the present invention, one or plural group attributes may be related to a single mail address/user name, and consequently, mails related to a group can be selectively displayed in response to input operation to designate the group.  
         [0097]     According to another aspect of the present invention, In order to add a new group and display mails of the group, it is required just to add a new group attribute to the group attribute information  201 . Displayed contents are independent of the structure of the mail data  401 .  
         [0098]     On the other hand, according to a conventional technique to classify mails into groups and store each group into a different folder, displayed contents are dependent on the structure of mail data. Therefore, in order to add a new group and mails of the group, it is required to move to other folders mails that belong to the new group.  
         [0099]     According to another aspect of the present Invention, the classification of a mail is dependent on its sender&#39;s address. Therefore, when a single sender uses plural mail addresses, the user of the portable communication terminal  101  can display a mail from the sender dependent on its mail address.  
         [0100]     While this invention has thus far been described in conjunction with a few embodiments thereof, it will be readily possible for those skilled in the art to put the this invention into various other manners.  
         [0101]     For example, in the above-mentioned embodiment, each mail address in the address book information  301  can be related to three group numbers  305  at a maximum. However, the present invention is not restricted to the embodiment. It is easily understood by those skilled in the art that four or more group numbers can be related to a single sender&#39;s address.  
         [0102]     Further, in the above-mentioned embodiment, as the group numbers  202  in the group attribute information  201 , numbers are used as identifiers for designating groups. However, any type of character or a string of characters Is available for the identifiers.  
         [0103]     Further, in the above-mentioned embodiment, the user selects a single group to designate mails to be displayed. However, plural groups may be designated. In this case, either sum of sets or set intersection of designated mails may be displayed.  
         [0104]     Further, in the above-mentioned embodiment, groups are related to sender&#39;s addresses. However, other items of the mail-data  401  are available for those to be related to groups. For example, keywords in the mail bodies  406  may be previously related to a group. In this case, mails whose mail body includes one of the keywords related to a designated group is displayed, The relation between groups and keywords may be stored in the classification information area  110 .