Package net.dv8tion.jda.api.exceptions

Class ErrorHandler

java.lang.Object

net.dv8tion.jda.api.exceptions.ErrorHandler

All Implemented Interfaces:

Consumer<Throwable>

public class ErrorHandler
extends Object
implements Consumer<Throwable>

Utility class to simplify error handling with RestActions and ErrorResponses.

Example

 // Send message to user and delete it 30 seconds later, handles blocked messages in context channel.
 public void sendMessage(TextChannel context, User user, String content) {
     user.openPrivateChannel()
         .flatMap(channel -> channel.sendMessage(content))
         .delay(Duration.ofSeconds(30))
         .flatMap(Message::delete) // delete after 30 seconds
         .queue(null, new ErrorHandler()
             .ignore(ErrorResponse.UNKNOWN_MESSAGE) // if delete fails that's fine
             .handle(
                 ErrorResponse.CANNOT_SEND_TO_USER,  // Fallback handling for blocked messages
                 (e) -> context.sendMessage("Failed to send message, you block private messages!").queue()));
 }
 

Since:

4.2.0

See Also:

ErrorResponse, ErrorResponseException, RestAction.queue(Consumer, Consumer)

Constructor Summary

Constructors

Constructor	Description
ErrorHandler()	Create an ErrorHandler with RestAction.getDefaultFailure() as base consumer.
ErrorHandler(Consumer<? super Throwable> base)	Create an ErrorHandler with the specified consumer as base consumer.

Method Summary

Modifier and Type	Method	Description
void	accept(Throwable t)
<T> ErrorHandler	handle(Class<T> clazz, Consumer<? super T> handler)	Handle specific throwable types.
<T> ErrorHandler	handle(Class<T> clazz, Predicate<? super T> condition, Consumer<? super T> handler)	Handle specific throwable types.
ErrorHandler	handle(Collection<Class<?>> clazz, Predicate<? super Throwable> condition, Consumer<? super Throwable> handler)	Handle specific throwable types.
ErrorHandler	handle(Collection<ErrorResponse> errorResponses, Consumer<? super ErrorResponseException> handler)	Handle specific ErrorResponses.
ErrorHandler	handle(Predicate<? super Throwable> condition, Consumer<? super Throwable> handler)	Handle specific conditions.
ErrorHandler	handle(ErrorResponse response, Consumer<? super ErrorResponseException> handler)	Handle specific ErrorResponses.
ErrorHandler	ignore(Class<?> clazz, Class<?>... classes)	Ignore exceptions of the specified types.
ErrorHandler	ignore(Collection<ErrorResponse> errorResponses)	Ignore the specified set of error responses.
ErrorHandler	ignore(Predicate<? super Throwable> condition)	Ignore exceptions on specific conditions.
ErrorHandler	ignore(ErrorResponse ignored, ErrorResponse... errorResponses)	Ignore the specified set of error responses.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.function.Consumer

andThen

Constructor Detail

ErrorHandler

public ErrorHandler()

Create an ErrorHandler with RestAction.getDefaultFailure() as base consumer.
If none of the provided ignore/handle cases apply, the base consumer is applied instead.

ErrorHandler

public ErrorHandler(@Nonnull
                    Consumer<? super Throwable> base)

Create an ErrorHandler with the specified consumer as base consumer.
If none of the provided ignore/handle cases apply, the base consumer is applied instead.

Parameters:

base - The base Consumer

Method Detail

ignore

@Nonnull
public ErrorHandler ignore(@Nonnull
                           ErrorResponse ignored,
                           @Nonnull
                           ErrorResponse... errorResponses)

Ignore the specified set of error responses.

Example

 // Creates a message with the provided content and deletes it 30 seconds later
 public static void selfDestruct(MessageChannel channel, String content) {
     channel.sendMessage(content)
         .delay(Duration.ofSeconds(30))
         .flatMap(Message::delete)
         .queue(null, new ErrorHandler().ignore(UNKNOWN_MESSAGE));
 }
 

Parameters:

ignored - Ignored error response

errorResponses - Additional error responses to ignore

Returns:

This ErrorHandler with the applied ignore cases

Throws:

IllegalArgumentException - If provided with null

ignore

@Nonnull
public ErrorHandler ignore(@Nonnull
                           Collection<ErrorResponse> errorResponses)

Ignore the specified set of error responses.

Example

 // Creates a message with the provided content and deletes it 30 seconds later
 public static void selfDestruct(User user, String content) {
     user.openPrivateChannel()
         .flatMap(channel -> channel.sendMessage(content))
         .delay(Duration.ofSeconds(30))
         .flatMap(Message::delete)
         .queue(null, new ErrorHandler().ignore(EnumSet.of(UNKNOWN_MESSAGE, CANNOT_SEND_TO_USER)));
 }
 

Parameters:

errorResponses - The error responses to ignore

Returns:

This ErrorHandler with the applied ignore cases

Throws:

IllegalArgumentException - If provided with null

ignore

@Nonnull
public ErrorHandler ignore(@Nonnull
                           Class<?> clazz,
                           @Nonnull
                           Class<?>... classes)

Ignore exceptions of the specified types.

Example

 // Ignore SocketTimeoutException
 public static void ban(Guild guild, String userId) {
     guild.ban(userId).queue(null, new ErrorHandler().ignore(SocketTimeoutException.class);
 }
 

Parameters:

clazz - The class to ignore

classes - Additional classes to ignore

Returns:

This ErrorHandler with the applied ignore case

Throws:

IllegalArgumentException - If provided with null

See Also:

SocketTimeoutException

ignore

@Nonnull
public ErrorHandler ignore(@Nonnull
                           Predicate<? super Throwable> condition)

Ignore exceptions on specific conditions.

Example

 // Ignore all exceptions except for ErrorResponseException
 public static void ban(Guild guild, String userId) {
     guild.ban(userId).queue(null, new ErrorHandler().ignore((ex) -> !(ex instanceof ErrorResponseException));
 }
 

Parameters:

condition - The condition to check

Returns:

This ErrorHandler with the applied ignore case

Throws:

IllegalArgumentException - If provided with null

See Also:

ErrorResponseException

handle

@Nonnull
public ErrorHandler handle(@Nonnull
                           ErrorResponse response,
                           @Nonnull
                           Consumer<? super ErrorResponseException> handler)

Handle specific ErrorResponses.
This will apply the specified handler to use instead of the base consumer if one of the provided ErrorResponses happens.

Example

 public static void sendMessage(TextChannel context, User user, String content) {
     user.openPrivateChannel()
         .flatMap(channel -> channel.sendMessage(content))
         .queue(null, new ErrorHandler()
             .handle(ErrorResponse.CANNOT_SEND_TO_USER,
                 (ex) -> context.sendMessage("Cannot send direct message, please enable direct messages from server members!").queue()));
 }
 

Parameters:

response - The first ErrorResponse to match

handler - The alternative handler

Returns:

This ErrorHandler with the applied handler

Throws:

IllegalArgumentException - If provided with null

handle

@Nonnull
public ErrorHandler handle(@Nonnull
                           Collection<ErrorResponse> errorResponses,
                           @Nonnull
                           Consumer<? super ErrorResponseException> handler)

Handle specific ErrorResponses.
This will apply the specified handler to use instead of the base consumer if one of the provided ErrorResponses happens.

Example

 public static void sendMessage(TextChannel context, User user, String content) {
     user.openPrivateChannel()
         .flatMap(channel -> channel.sendMessage(content))
         .queue(null, new ErrorHandler()
             .handle(EnumSet.of(ErrorResponse.CANNOT_SEND_TO_USER),
                 (ex) -> context.sendMessage("Cannot send direct message, please enable direct messages from server members!").queue()));
 }
 

Parameters:

errorResponses - The ErrorResponses to match

handler - The alternative handler

Returns:

This ErrorHandler with the applied handler

Throws:

IllegalArgumentException - If provided with null

handle

@Nonnull
public <T> ErrorHandler handle(@Nonnull
                               Class<T> clazz,
                               @Nonnull
                               Consumer<? super T> handler)

Handle specific throwable types.
This will apply the specified handler if the throwable is of the specified type. The check is done using Class.isInstance(Object).

Example

 public static void logErrorResponse(RestAction<?> action) {
     action.queue(null, new ErrorHandler()
         .handle(ErrorResponseException.class,
             (ex) -> System.out.println(ex.getErrorResponse())));
 }
 

Type Parameters:

T - The type

Parameters:

clazz - The throwable type

handler - The alternative handler

Returns:

This ErrorHandler with the applied handler

handle

@Nonnull
public <T> ErrorHandler handle(@Nonnull
                               Class<T> clazz,
                               @Nonnull
                               Predicate<? super T> condition,
                               @Nonnull
                               Consumer<? super T> handler)

Handle specific throwable types.
This will apply the specified handler if the throwable is of the specified type. The check is done using Class.isInstance(Object).

Example

 public static void logErrorResponse(RestAction<?> action) {
     action.queue(null, new ErrorHandler()
         .handle(ErrorResponseException.class,
             ErrorResponseException::isServerError,
             (ex) -> System.out.println(ex.getErrorCode() + ": " + ex.getMeaning())));
 }
 

Type Parameters:

T - The type

Parameters:

clazz - The throwable type

condition - Additional condition that must apply to use this handler

handler - The alternative handler

Returns:

This ErrorHandler with the applied handler

handle

@Nonnull
public ErrorHandler handle(@Nonnull
                           Collection<Class<?>> clazz,
                           @Nullable
                           Predicate<? super Throwable> condition,
                           @Nonnull
                           Consumer<? super Throwable> handler)

Handle specific throwable types.
This will apply the specified handler if the throwable is of the specified type. The check is done using Class.isInstance(Object).

Example

 public static void logErrorResponse(RestAction<?> action) {
     action.queue(null, new ErrorHandler()
         .handle(Arrays.asList(Throwable.class),
             (ex) -> ex instanceof Error,
             (ex) -> ex.printStackTrace()));
 }
 

Parameters:

clazz - The throwable types

condition - Additional condition that must apply to use this handler, or null to apply no additional condition

handler - The alternative handler

Returns:

This ErrorHandler with the applied handler

handle

@Nonnull
public ErrorHandler handle(@Nonnull
                           Predicate<? super Throwable> condition,
                           @Nonnull
                           Consumer<? super Throwable> handler)

Handle specific conditions.

Example

 public static void logErrorResponse(RestAction<?> action) {
     action.queue(null, new ErrorHandler()
         .handle(
             (ex) -> !(ex instanceof ErrorResponseException),
             Throwable::printStackTrace));
 }
 

Parameters:

condition - Condition that must apply to use this handler

handler - The alternative handler

Returns:

This ErrorHandler with the applied handler

accept

public void accept(Throwable t)

Specified by:

accept in interface Consumer<Throwable>