Overview
The Hash Map category of actions allow
you to store and retrieve the value of a variable based on
groups and keys that are represented as strings. Optimized
for performance, the hash map actions enables you to
quickly create an internal object model for dynamic
metadata that might be required by your application
program.
It is important to understand that the hash map was designed to be very fast and to use in-memory persistence that is lost when the node is restarted. For information regarding a storage solution that will persist across node restarts, see Local Database.
Key features of the hash map
There is one global hash map within a given node.The hash map provides a group and key level as follows:
- Group
There can be one or more groups within the node. The group is the first level of organization and can be any string.
Use a group when you want to iterate through a list of entries on the hash map. Because groups do not contain values, they cannot be directly searched for or listed. - Key
The key is the second level of organization. Each key must be unique within its group. There can be one or more keys within each group.
You can search for a single key, but the search will look for an exact match.
The following illustrates the components of a hash
map:
Viewing the hash map
Once data is generated by the trigger, you can view or or delete the data contained in the hash map. The data becomes available from the Hash Map Variables tab.
The following shows an example hash map:
The Hash Map category provides these
actions: