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update persistence documentation (#2318) 

Signed-off-by: Mark Herwege <mark.herwege@telenet.be>
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Mark Herwege 2024-06-30 13:30:12 +02:00 committed by GitHub
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configuration/persistence.md
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@ -245,8 +245,10 @@ Here is the full list of available persistence extensions:
| `<item>.persist(ZonedDateTime, State)` | Persists a past or future state for the Item | | `<item>.persist(ZonedDateTime, State)` | Persists a past or future state for the Item |
| `<item>.persist(TimeSeries)` | Persists a TimeSeries with one or multiple values to the Item | | `<item>.persist(TimeSeries)` | Persists a TimeSeries with one or multiple values to the Item |
| `<item>.persistedState(ZonedDateTime)` | Retrieves the State of an Item at a certain point in time (returns HistoricItem) | | `<item>.persistedState(ZonedDateTime)` | Retrieves the State of an Item at a certain point in time (returns HistoricItem) |
| `<item>.lastUpdate()` | Returns the timestamp of the last Item update | | `<item>.lastUpdate()` | Returns the timestamp of the last Item update, null if current Item state different from last persisted state |
| `<item>.nextUpdate()` | Returns the timestamp of the next Item update if future states have been persisted | | `<item>.nextUpdate()` | Returns the timestamp of the next Item update if future states have been persisted |
| `<item>.lastChange()` | Returns the timestamp of the last Item change, null if current Item state different from last persisted state |
| `<item>.nextChange()` | Returns the timestamp of the next Item change if future states have been persisted |
| `<item>.previousState()` | Gets the previous State of a persisted Item (returns HistoricItem) | | `<item>.previousState()` | Gets the previous State of a persisted Item (returns HistoricItem) |
| `<item>.previousState(true)` | Gets the previous State of a persisted Item, skips Items with equal State values and searches the first Item with State not equal the current State (returns HistoricItem) | | `<item>.previousState(true)` | Gets the previous State of a persisted Item, skips Items with equal State values and searches the first Item with State not equal the current State (returns HistoricItem) |
| `<item>.nextState()` | Gets the next State of a persisted Item if future states have been persisted (returns HistoricItem) | | `<item>.nextState()` | Gets the next State of a persisted Item if future states have been persisted (returns HistoricItem) |
@ -308,6 +310,13 @@ The most useful methods of the HistoricItem object returned by some queries, are
To persist an Item called `Lights` in an rrd4j database, you would enter the following: To persist an Item called `Lights` in an rrd4j database, you would enter the following:
`Lights.persist("rrd4j")` `Lights.persist("rrd4j")`
To get the time of the last change of an Item `Humidity` from the default persistence service, default to the current time if the last persisted state is different from the current state:
```java
var lastChange = Humidity.lastChange()
lastChange = (lastChange !== null) ? lastChange : now
```
To get the average temperature over the last 5 minutes from the Item called `Temperature` in the influxdb persistence service, you would use: To get the average temperature over the last 5 minutes from the Item called `Temperature` in the influxdb persistence service, you would use:
`Temperature.averageSince(now.minusMinutes(5), "influxdb")` `Temperature.averageSince(now.minusMinutes(5), "influxdb")`