getStatistics

getStatistics(statistics: JadeDynamicObject input) abstract;

The getStatistics method of the Collection class analyzes the collection and returns structural statistics in the attributes of a JadeDynamicObject, representing collection statistics.

The attributes of a collection statistics dynamic object are defined and interpreted as follows.

Attribute	Description
blockSize	Entries per block
keyLength	Size of the key in bytes (oid (6) for Set classes and Integer (4) for Array classes)
entrySize	Size of each collection entry in bytes
size	Number of entries in the collection (that is, the size of the collection itself)
blockCount	Total number of blocks in the collection
height	Number of levels in the collection (always 1 for Array classes)
minEntries	Minimum number of entries found in any block
maxEntries	Maximum number of entries found in any block
avgEntries	Average number of entries in collection blocks
loadFactor	Actual average percent loading of collection blocks (entries for each block)

To compute the block size in bytes, multiply the blockSize attribute by the entrySize attribute. The maximum collection block size for a collection is 256K bytes (that is, the value defined by the MaximumCollectionBlockSize global constant in the SystemLimits category).

The JadeDynamicObjectNames category global constants for collection statistics are listed in the following table, where the name of the dynamic object represents the collection type of the receiver.

Global Constant	String Value
JStats_ArrayName	"JStatsArray"
JStats_DictionaryName	"JStatsDictionary"
JStats_JadeBytesName	"JStatsJadeBytes"
JStats_SetName	"JStatsName"

The JadeDynamicObjectTypes category global constants for collection statistics are listed in the following table, where the type of the dynamic object represents the collection type of the receiver.

Global Constant	Integer Value
JStats_ArrayType	101
JStats_DictionaryType	102
JStats_JadeBytesType	104
JStats_SetType	103

The following example shows the use of the getStatistics method.

vars
    jdo : JadeDynamicObject;
begin
    create jdo;
    node.processes.getStatistics(jdo);
    write jdo.display;
epilog
    delete jdo;
end;

For details about the behavior and tuning of collections, see Chapter 4 of the Developer's Reference.