The additional APIs for large lists

Runtime components : Service components : Remote cache service : Class and API reference : The additional APIs for large lists

Additional APIs for use with large lists

See

Push list

abstract public long list_push(IndexedCollection list, String key, long index) throws IOException

Push list <list> to remote list (in the cache) with key <key> at index position <index>.

Returns the size of the remote list.

Note

▪ If the remote list does not exist, the list is created.

▪ You can add elements to the beginning or the end of an existing list. For performance reasons, you cannot add elements in the middle of the list.

▪ Normally the list is only a small part of the remote list; to build a large remote list, call this method multiple times.

▪ Do not attempt to overwrite existing data. Instead, delete the remote list by using list_drop(list,key) and create a new list.

The following table describes the parameters:

Parameter	Description
List	The data to be pushed. Defines the Cache_List_Key_Set parameter for filtering on poll at a later date.
Key	The key for the remote list
Index	The record position (in the remote list) to which data is pushed. Supported options are: ▪ LIST_HEAD: 0 (the first record) ▪ LIST_TAIL: -1 (the last record)

Push Record

abstract public long list_push(IndexedCollection list, KeyedCollection record, String key, long index) throws IOException

Push record <record> to remote List (in the cache) with key <key> at index position <index>.

Provides the definition for the remote list, and pushes a record to the remote list.

Set List

abstract public boolean list_set (IndexedCollection list, KeyedCollection record, String key, long index) throws IOException ;

Set(replace) the <record> of the remote List with <key> at position <index>.

The following table describes the parameters:

Parameter	Description
List	Read only and will not be pushed to remote, it only provides the <Cache_List_Key_Set> definition
Record	The data to be updated (replaced with), read only
Key	The key for the remote list
Index	The record position (in the remote list) to be updated (replaced with), start from 0 ▪ LIST_HEAD or 0 denotes the first record

Pull List

abstract public long list_pull(IndexedCollection list, String key, String filter, long index, long stop) throws IOException

Pull data from the remote List with <key> to <list> and using <filter> to filter the remote List from <index>(0 based) to <stop>(include)

The following table describes the parameters:

Parameter	Description
List	Data to be pulled from remote; its local data would be cleared and overwritten
Key	The key for the remote list
Filter	▪ Define the criteria for the current record of the remote List on pull, count and find operations. ▪ Define a Lua expression that returns a Boolean value to indicate whether the current record is included (true) or not (false). ▪ You can reference the indexed field of the current record of the list in the form of ‘R["dataFieldName"]’as a Lua string value. To use it as number: number(R["dataFieldName"]) ▪ You can reference the position of the current record with POS, start from 0; ▪ You can use these Lua functions/libs in the expression: tonumber -- tostring -- math -- string -- table Example: tonumber(R["found.balance"]) > 100 and POS < 10 Where "found.balance" should be in the Cache_List_Key_Set index.
Index	The record position (in the remote list) to begin the process, starting from 0 ▪ LIST_HEAD or 0 denotes the first record

Count list

abstract public long list_count(IndexedCollection list, String key, String filter, long index, long stop)

Count the <list> items matching < filter > from <index> to <stop>

Returns only the count number of matched records, and no other data.

Find list

abstract public long list_find(IndexedCollection list, String key, String filter, long index) throws IOException ;

Find the item matching <filter> of remote <list> from <index>

Returns only the index number of the first matched record, no other data.

Pop list

abstract public boolean list_pop (IndexedCollection list, KeyedCollection record, String key, long index) throws IOException ;

Pop out ONE record from the head (<index>=LIST_HEAD) or tail (<index>=LIST_TAIL) of the remote List with <key> to local <record>

Parameter	Description
List	Read only and will not be pushed to remote, it only provides the <Cache_List_Key_Set> definition
Record	The popped data that will overwrite local data
Key	The key for the remote list
Index	The record position (in the remote list) to be popped out. Supported options are: ▪ LIST_HEAD: 0 (the first record) ▪ LIST_TAIL: -1 (the last record)

Trim list

abstract public boolean list_trim(IndexedCollection list, String key, long index, long stop) throws IOException ;

Trim the remote List with <key> to new size(from <index> to <stop>) and drop other records([0~<index>] and [stop+1, LIST_TAIL])

Parameter	Description
List	Read only and only provides the <Cache_List_Key_Set> definition of the remote list.
Key	The key for the remote list
Index	The first record position at remote List to KEEP, start from 0 Supported options are: ▪ LIST_HEAD: 0 (the first record) ▪ LIST_TAIL: -1 (the last record)
Stop	The last record position at remote List to KEEP, start from 0 This can also be negative numbers, indicating offsets starting from the end of the list. For example, LIST_TAIL or -1 denotes the last record of the remote list, -2 the penultimate, and so on.

Get list

abstract public boolean list_get (KeyedCollection record, String key, long index) throws IOException ;

Get <record> from the remote List with <key> by <index>

Parameter	Description
Record	The data to be saved to, its local data would be cleared and overwritten
Key	The key for the remote list
Index	The first record position at remote List to get, start from 0 ▪ LIST_HEAD: 0 (the first record) This can also be negative numbers, indicating offsets starting from the end of the list. ▪ For example, LIST_TAIL or -1 denotes the last record of the remote list, -2 the penultimate, and so on.

List size

abstract public long list_size (String key) ;

Get the size of the remote List with <key>

Drop list

abstract public boolean list_drop (IndexedCollection list, String key);

Drop the remote List with <key> completely.