PrePut (Google App Engine API for Java)
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@Target(value=METHOD)
@Retention(value=RUNTIME)
public @interface PrePut
Identifies a callback method to be invoked before an
Entity
of any of the specified kinds
is written to the datastore. If
kinds()
is not provided the callback will execute for
all kinds. Methods with this annotation must return
void
, must accept a single argument
of type
PutContext
, must not throw any checked exceptions, must not be static, and must
belong to a class with a no-arg constructor. Neither the method nor the no-arg constructor of the
class to which it belongs are required to be public. Methods with this annotation are free to
throw any unchecked exception they like. Throwing an unchecked exception will prevent callbacks
that have not yet been executed from running, and the exception will propagate to the code that
invoked the datastore operation that resulted in the invocation of the callback. Throwing an
unchecked exception from a callback will prevent the datastore operation from executing.
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Optional Element Summary
Optional Elements
Modifier and Type |
Optional Element and Description |
java.lang.String[] |
kinds
The kinds to which this callback applies.
|
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Last updated 2025-06-16 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-06-16 UTC."],[[["The `@PrePut` annotation identifies a callback method that is invoked before an `Entity` is written to the datastore."],["Methods annotated with `@PrePut` must return `void`, accept a single `PutContext` argument, and belong to a class with a no-arg constructor."],["The `kinds()` element within `@PrePut` specifies the types of `Entity` to which the callback applies, and if left unspecified, the callback executes for all kinds."],["Throwing an unchecked exception from a `@PrePut` callback method will prevent further callbacks from running and halt the datastore operation."]]],[]]