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TemporalQuery
@FunctionalInterface interface TemporalQuery<R : Any!>
Strategy for querying a temporal object.
Queries are a key tool for extracting information from temporal objects. They exist to externalize the process of querying, permitting different approaches, as per the strategy design pattern. Examples might be a query that checks if the date is the day before February 29th in a leap year, or calculates the number of days to your next birthday.
The TemporalField interface provides another mechanism for querying temporal objects. That interface is limited to returning a long. By contrast, queries can return any type.
There are two equivalent ways of using a TemporalQuery. The first is to invoke the method on this interface directly. The second is to use TemporalAccessor.query(TemporalQuery):
// these two lines are equivalent, but the second approach is recommended
temporal = thisQuery.queryFrom(temporal);
temporal = temporal.query(thisQuery);
It is recommended to use the second approach,
query(TemporalQuery), as it is a lot clearer to read in code.
The most common implementations are method references, such as LocalDate::from and ZoneId::from. Additional common queries are provided as static methods in TemporalQueries.
Summary
| Public methods |
| abstract R |
Queries the specified temporal object.
|
Public methods
queryFrom
abstract fun queryFrom(temporal: TemporalAccessor!): R
Queries the specified temporal object.
This queries the specified temporal object to return an object using the logic encapsulated in the implementing class. Examples might be a query that checks if the date is the day before February 29th in a leap year, or calculates the number of days to your next birthday.
There are two equivalent ways of using this method. The first is to invoke this method directly. The second is to use TemporalAccessor.query(TemporalQuery):
// these two lines are equivalent, but the second approach is recommended
temporal = thisQuery.queryFrom(temporal);
temporal = temporal.query(thisQuery);
It is recommended to use the second approach,
query(TemporalQuery), as it is a lot clearer to read in code.
| Return |
R |
the queried value, may return null to indicate not found |
| Exceptions |
java.time.DateTimeException |
if unable to query |
java.lang.ArithmeticException |
if numeric overflow occurs |
Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
Last updated 2025-02-10 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-02-10 UTC."],[],[],null,["# TemporalQuery\n\nAdded in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)\n\nTemporalQuery\n=============\n\n```\n@FunctionalInterface interface TemporalQuery\u003cR : Any!\u003e\n```\n\n|---------------------------------------|\n| [java.time.temporal.TemporalQuery](#) |\n\nStrategy for querying a temporal object.\n\nQueries are a key tool for extracting information from temporal objects. They exist to externalize the process of querying, permitting different approaches, as per the strategy design pattern. Examples might be a query that checks if the date is the day before February 29th in a leap year, or calculates the number of days to your next birthday.\n\nThe [TemporalField](/reference/kotlin/java/time/temporal/TemporalField) interface provides another mechanism for querying temporal objects. That interface is limited to returning a `long`. By contrast, queries can return any type.\n\nThere are two equivalent ways of using a `TemporalQuery`. The first is to invoke the method on this interface directly. The second is to use [TemporalAccessor.query(TemporalQuery)](/reference/kotlin/java/time/temporal/TemporalAccessor#query(java.time.temporal.TemporalQuery)): \n\n```kotlin\n// these two lines are equivalent, but the second approach is recommended\n temporal = thisQuery.queryFrom(temporal);\n temporal = temporal.query(thisQuery);\n \n```\nIt is recommended to use the second approach, `query(TemporalQuery)`, as it is a lot clearer to read in code.\n\nThe most common implementations are method references, such as `LocalDate::from` and `ZoneId::from`. Additional common queries are provided as static methods in [TemporalQueries](/reference/kotlin/java/time/temporal/TemporalQueries).\n\nSummary\n-------\n\n| Public methods ||\n|------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| abstract R | [queryFrom](#queryFrom(java.time.temporal.TemporalAccessor))`(`temporal:` `[TemporalAccessor](/reference/kotlin/java/time/temporal/TemporalAccessor)!`)` Queries the specified temporal object. |\n\nPublic methods\n--------------\n\n### queryFrom\n\nAdded in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nabstract fun queryFrom(temporal: TemporalAccessor!): R\n```\n\nQueries the specified temporal object.\n\nThis queries the specified temporal object to return an object using the logic encapsulated in the implementing class. Examples might be a query that checks if the date is the day before February 29th in a leap year, or calculates the number of days to your next birthday.\n\nThere are two equivalent ways of using this method. The first is to invoke this method directly. The second is to use [TemporalAccessor.query(TemporalQuery)](/reference/kotlin/java/time/temporal/TemporalAccessor#query(java.time.temporal.TemporalQuery)): \n\n```kotlin\n// these two lines are equivalent, but the second approach is recommended\n temporal = thisQuery.queryFrom(temporal);\n temporal = temporal.query(thisQuery);\n \n```\nIt is recommended to use the second approach, `query(TemporalQuery)`, as it is a lot clearer to read in code.\n\n| Parameters ||\n|------------|--------------------------------------------------------------------------------------------------------------------|\n| `temporal` | [TemporalAccessor](/reference/kotlin/java/time/temporal/TemporalAccessor)!: the temporal object to query, not null |\n\n| Return ||\n|---|----------------------------------------------------------|\n| R | the queried value, may return null to indicate not found |\n\n| Exceptions ||\n|---------------------------------|----------------------------|\n| `java.time.DateTimeException` | if unable to query |\n| `java.lang.ArithmeticException` | if numeric overflow occurs |"]]
