Pseudo-Properties for Collections

There are some special properties of collections that OGNL makes available. The reason for this is that the collections do not follow JavaBeans patterns for method naming; therefore the size(), length(), etc. methods must be called instead of more intuitively referring to these as properties. OGNL corrects this by exposing certain pseudo-properties as if they were built-in.

Table 4.1. Special Collections Pseudo-Properties

CollectionSpecial Properties
Collection (inherited by Map, List & Set)
size

The size of the collection

isEmpty

Evaluates to true if the collection is empty

List
iterator

Evalutes to an Iterator over the List.

Map
keys

Evalutes to a Set of all keys in the Map.

values

Evaluates to a Collection of all values in the Map.

[Note]Note

These properties, plus size and isEmpty, are different than the indexed form of access for Maps (i.e. someMap["size"] gets the "size" key from the map, whereas someMap.size gets the size of the Map.

Set
iterator

Evalutes to an Iterator over the Set.

Iterator
next

Evalutes to the next object from the Iterator.

hasNext

Evaluates to true if there is a next object available from the Iterator.

Enumeration
next

Evalutes to the next object from the Enumeration.

hasNext

Evaluates to true if there is a next object available from the Enumeration.

nextElement

Synonym for next.

hasMoreElements

Synonym for hasNext.