Apple Newton Utilities User's Guide download pdf (Page 493)

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101

CHAPTER 11

Data Storage and Retrieval

Using Newton Data Storage Objects 11-61

Copying Entries 11

The EntryCopyXmit global function and the CopyEntriesXmit soup method

enable you to copy entries from one soup to another and transmit appropriate

change notiﬁcations.

The following code fragment uses the

CopyEntriesXmit soup method to copy

all the entries from a speciﬁed source soup into a speciﬁed destination soup. Note

that this method is deﬁned only for soups, not for union soups. The following code

fragment uses the

GetMember union soup method to retrieve the plain soup

constituent of a union soup from a speciﬁed store. The

GetMember method never

returns

nil; instead, it creates an empty member soup on the speciﬁed store if one

does not already exist:

// myUsoup member on internal store is the source soup

local myUSoup := GetUnionSoupAlways("myUSoup:mySig");

local sourceSoup := myUSoup:GetMember(GetStores()[0])

// myUsoup member on another store is the destination soup

local destSoup := myUSoup:GetMember(GetStores()[1]);

// copy all entries from source soup to dest soup

local cursor := sourceSoup:Query(nil);

if (cursor:CountEntries() <> 0) then

sourceSoup:CopyEntriesXmit(destSoup, '|MyApp:MySig|);

You can use the EntryCopyXmit function to copy an entry from a speciﬁed

source soup to a speciﬁed destination soup and transmit a soup change notiﬁcation

message. Note that this function is deﬁned only for soups, not for union soups. The

following code fragment uses the

GetSoup store method to retrieve a speciﬁed

soup from its store. Because the

GetSoup method returns nil when the soup to

be retrieved is not available, you must at least ensure that this result is non-

nil

before using it. The following code fragment actually goes one step further and

uses the

IsValid soup method to test the validity of the destSoup soup in

additional ways:

local myUSoup := GetUnionSoupAlways("myUSoup:mySig");

// get all entries having 'hot in 'temperature slot

local cursor := myUSoup:Query({indexPath: 'temperature,

beginKey: 'hot

endKey: 'hot});

local destSoup := GetStores()[0]:GetSoup("mySoup:mySig");

// make sure we actually got a valid soup

if destSoup:IsValid() then

begin

// xmit a single notification after all changes are made

while e := cursor:Entry() do EntryCopyXmit(e,destSoup,nil);

XmitSoupChange(destSoup, '|MyApp:MySig|, 'whatThe, nil);

end;

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