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Chapter 5. Working with Counters
Counters provide atomic increment and decrement operations that record the count of objects.
Prerequisites
- Start the Data Grid CLI.
- Connect to a running Data Grid cluster.
5.1. Creating Counters Copier lienLien copié sur presse-papiers!
Create strong and weak counters with the Data Grid CLI.
Procedure
- Create a CLI connection to Data Grid.
Run the
create countercommand with the appropriate arguments.Create
my-weak-counter.create counter --concurrency-level=1 --initial-value=5 --storage=PERSISTENT --type=weak my-weak-counter
create counter --concurrency-level=1 --initial-value=5 --storage=PERSISTENT --type=weak my-weak-counterCopy to Clipboard Copied! Toggle word wrap Toggle overflow Create
my-strong-counter.create counter --initial-value=3 --storage=PERSISTENT --type=strong my-strong-counter
create counter --initial-value=3 --storage=PERSISTENT --type=strong my-strong-counterCopy to Clipboard Copied! Toggle word wrap Toggle overflow
List available counters.
ls counters
ls countersCopy to Clipboard Copied! Toggle word wrap Toggle overflow Verify counter configurations.
Describe
my-weak-counter.describe counters/my-weak-counter
describe counters/my-weak-counterCopy to Clipboard Copied! Toggle word wrap Toggle overflow Copy to Clipboard Copied! Toggle word wrap Toggle overflow Describe
my-strong-counter.describe counters/my-strong-counter
describe counters/my-strong-counterCopy to Clipboard Copied! Toggle word wrap Toggle overflow Copy to Clipboard Copied! Toggle word wrap Toggle overflow
5.2. Adding Deltas to Counters Copier lienLien copié sur presse-papiers!
Increment or decrement counters with arbitrary values.
Procedure
Select a counter.
counter my-weak-counter
counter my-weak-counterCopy to Clipboard Copied! Toggle word wrap Toggle overflow List the current count.
[//containers/default/counters/my-weak-counter]> ls 5
[//containers/default/counters/my-weak-counter]> ls 5Copy to Clipboard Copied! Toggle word wrap Toggle overflow Increment the counter value by
2.[//containers/default/counters/my-weak-counter]> add --delta=2
[//containers/default/counters/my-weak-counter]> add --delta=2Copy to Clipboard Copied! Toggle word wrap Toggle overflow Decrement the counter value by
-4.[//containers/default/counters/my-weak-counter]> add --delta=-4
[//containers/default/counters/my-weak-counter]> add --delta=-4Copy to Clipboard Copied! Toggle word wrap Toggle overflow
Strong counters return values after the operation is applied. Use --quiet=true to hide the return value.
For example, add --delta=3 --quiet=true.
Weak counters return empty responses.