Package com.vaadin.flow.component.page

Interface PendingJavaScriptResult

All Superinterfaces:

Page.ExecutionCanceler, Serializable

All Known Implementing Classes:

PendingJavaScriptInvocation

public interface PendingJavaScriptResult
extends Serializable, Page.ExecutionCanceler

A pending result from a JavaScript snippet sent to the browser for evaluation.

If any of the then or toCompletableFuture methods have been invoked before the snippet is sent to the browser, then the there will be an additional round trip for sending the results of the evaluation back to any registered handler. If the JavaScript execution returns a Promise, then the result will be sent to the server only when it is resolved.

It is not possible to add handlers after the invocation has been sent to the browser since the original result would in that case already be discarded.

Since:

2.0

Author:

Vaadin Ltd

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	PendingJavaScriptResult.JavaScriptException	Exception used when a CompletableFuture returned from PendingJavaScriptResult is completed exceptionally because of a client-side error.

Method Summary

Modifier and Type	Method	Description
boolean	cancelExecution()	Cancel the javascript execution, if it was not yet sent to the browser for execution.
boolean	isSentToBrowser()	Checks whether the JavaScript execution has already been sent to the browser.
default void	then(SerializableConsumer<elemental.json.JsonValue> resultHandler)	Adds an untyped handler that will be run for a successful execution.
void	then(SerializableConsumer<elemental.json.JsonValue> resultHandler, SerializableConsumer<String> errorHandler)	Adds an untyped handler that will be run for a successful execution and a handler that will be run for a failed execution.
default <T> void	then(Class<T> targetType, SerializableConsumer<T> resultHandler)	Adds a typed handler that will be run for a successful execution.
default <T> void	then(Class<T> targetType, SerializableConsumer<T> resultHandler, SerializableConsumer<String> errorHandler)	Adds a typed handler that will be run for a successful execution and a handler that will be run for a failed execution.
default CompletableFuture<elemental.json.JsonValue>	toCompletableFuture()	Creates an untyped completable future that will be completed with the result of the execution.
default <T> CompletableFuture<T>	toCompletableFuture(Class<T> targetType)	Creates a typed completable future that will be completed with the result of the execution.

Method Detail

cancelExecution

boolean cancelExecution()

Cancel the javascript execution, if it was not yet sent to the browser for execution.

Specified by:

cancelExecution in interface Page.ExecutionCanceler

Returns:

true if the execution was canceled, false if not

isSentToBrowser

boolean isSentToBrowser()

Checks whether the JavaScript execution has already been sent to the browser. It is no longer possible to cancel the execution or add a handler for the result after the execution has been sent.

Returns:

true if the execution is sent to the browser, false if it's still pending

then

default <T> void then(Class<T> targetType,
                      SerializableConsumer<T> resultHandler,
                      SerializableConsumer<String> errorHandler)

Adds a typed handler that will be run for a successful execution and a handler that will be run for a failed execution. One of the handlers will be invoked asynchronously when the result of the execution is sent back to the server.

Handlers can only be added before the execution has been sent to the browser.

Parameters:

targetType - the type to convert the JavaScript return value to, not null

resultHandler - a handler for the return value from a successful execution, not null

errorHandler - a handler for an error message in case the execution failed, or null to ignore errors

then

default <T> void then(Class<T> targetType,
                      SerializableConsumer<T> resultHandler)

Adds a typed handler that will be run for a successful execution. The handler will be invoked asynchronously if the execution was successful. In case of a failure, no handler will be run.

A handler can only be added before the execution has been sent to the browser.

Parameters:

targetType - the type to convert the JavaScript return value to, not null

resultHandler - a handler for the return value from a successful execution, not null

toCompletableFuture

default <T> CompletableFuture<T> toCompletableFuture(Class<T> targetType)

Creates a typed completable future that will be completed with the result of the execution. It will be completed asynchronously when the result of the execution is sent back to the server. It is not possible to synchronously wait for the result of the execution while holding the session lock since the request handling thread that makes the result available will also need to lock the session.

A completable future can only be created before the execution has been sent to the browser.

Parameters:

targetType - the type to convert the JavaScript return value to, not null

Returns:

a completable future that will be completed based on the execution results, not null

then

void then(SerializableConsumer<elemental.json.JsonValue> resultHandler,
          SerializableConsumer<String> errorHandler)

Adds an untyped handler that will be run for a successful execution and a handler that will be run for a failed execution. One of the handlers will be invoked asynchronously when the result of the execution is sent back to the server. It is not possible to synchronously wait for the result of the execution while holding the session lock since the request handling thread that makes the result available will also need to lock the session.

Handlers can only be added before the execution has been sent to the browser.

Parameters:

resultHandler - a handler for the JSON representation of the value from a successful execution, not null

errorHandler - a handler for an error message in case the execution failed, or null to ignore errors

then

default void then(SerializableConsumer<elemental.json.JsonValue> resultHandler)

Adds an untyped handler that will be run for a successful execution. The handler will be invoked asynchronously if the execution was successful. In case of a failure, no handler will be run.

A handler can only be added before the execution has been sent to the browser.

Parameters:

resultHandler - a handler for the JSON representation of the return value from a successful execution, not null

toCompletableFuture

default CompletableFuture<elemental.json.JsonValue> toCompletableFuture()

Creates an untyped completable future that will be completed with the result of the execution. It will be completed asynchronously when the result of the execution is sent back to the server.

A completable future can only be created before the execution has been sent to the browser.

Returns:

a completable future that will be completed based on the execution results, not null