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/*
* Copyright 2015 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.dv8tion.jda.api.exceptions;
import net.dv8tion.jda.api.requests.ErrorResponse;
import net.dv8tion.jda.api.requests.RestAction;
import net.dv8tion.jda.internal.utils.Checks;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.*;
import java.util.function.Consumer;
import java.util.function.Predicate;
/**
* Utility class to simplify error handling with {@link RestAction RestActions} and {@link ErrorResponse ErrorResponses}.
*
* Example
*
{@code
* // 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()));
* }
* }
*
* @see ErrorResponse
* @see ErrorResponseException
* @see RestAction#queue(Consumer, Consumer)
*
* @since 4.2.0
*/
public class ErrorHandler implements Consumer
{
private static final Consumer empty = (e) -> {};
private final Consumer base;
private final Map, Consumer> cases = new LinkedHashMap<>();
/**
* Create an ErrorHandler with {@link RestAction#getDefaultFailure()} as base consumer.
*
If none of the provided ignore/handle cases apply, the base consumer is applied instead.
*/
public ErrorHandler()
{
this(RestAction.getDefaultFailure());
}
/**
* 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.
*
* @param base
* The base {@link Consumer}
*/
public ErrorHandler(@Nonnull Consumer base)
{
Checks.notNull(base, "Consumer");
this.base = base;
}
/**
* Ignore the specified set of error responses.
*
* Example
*
{@code
* // 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));
* }
* }
*
* @param ignored
* Ignored error response
* @param errorResponses
* Additional error responses to ignore
*
* @throws IllegalArgumentException
* If provided with null
*
* @return This ErrorHandler with the applied ignore cases
*/
@Nonnull
public ErrorHandler ignore(@Nonnull ErrorResponse ignored, @Nonnull ErrorResponse... errorResponses)
{
Checks.notNull(ignored, "ErrorResponse");
Checks.noneNull(errorResponses, "ErrorResponse");
return ignore(EnumSet.of(ignored, errorResponses));
}
/**
* Ignore the specified set of error responses.
*
* Example
*
{@code
* // 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)));
* }
* }
*
* @param errorResponses
* The error responses to ignore
*
* @throws IllegalArgumentException
* If provided with null
*
* @return This ErrorHandler with the applied ignore cases
*/
@Nonnull
public ErrorHandler ignore(@Nonnull Collection errorResponses)
{
return handle(errorResponses, empty);
}
/**
* Ignore exceptions of the specified types.
*
* Example
*
{@code
* // Ignore SocketTimeoutException
* public static void ban(Guild guild, String userId) {
* guild.ban(userId).queue(null, new ErrorHandler().ignore(SocketTimeoutException.class);
* }
* }
*
* @param clazz
* The class to ignore
* @param classes
* Additional classes to ignore
*
* @throws IllegalArgumentException
* If provided with null
*
* @return This ErrorHandler with the applied ignore case
*
* @see java.net.SocketTimeoutException
*/
@Nonnull
public ErrorHandler ignore(@Nonnull Class clazz, @Nonnull Class... classes)
{
Checks.notNull(clazz, "Classes");
Checks.noneNull(classes, "Classes");
return ignore(it -> {
if (clazz.isInstance(it))
return true;
for (Class e : classes)
{
if (e.isInstance(it))
return true;
}
return false;
});
}
/**
* Ignore exceptions on specific conditions.
*
* Example
*
{@code
* // 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));
* }
* }
*
* @param condition
* The condition to check
*
* @throws IllegalArgumentException
* If provided with null
*
* @return This ErrorHandler with the applied ignore case
*
* @see ErrorResponseException
*/
@Nonnull
public ErrorHandler ignore(@Nonnull Predicate condition)
{
return handle(condition, empty);
}
/**
* Handle specific {@link ErrorResponse ErrorResponses}.
*
This will apply the specified handler to use instead of the base consumer if one of the provided ErrorResponses happens.
*
* Example
*
{@code
* 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()));
* }
* }
*
* @param response
* The first {@link ErrorResponse} to match
* @param handler
* The alternative handler
*
* @throws IllegalArgumentException
* If provided with null
*
* @return This ErrorHandler with the applied handler
*/
@Nonnull
public ErrorHandler handle(@Nonnull ErrorResponse response, @Nonnull Consumer handler)
{
Checks.notNull(response, "ErrorResponse");
return handle(EnumSet.of(response), handler);
}
/**
* Handle specific {@link ErrorResponse ErrorResponses}.
*
This will apply the specified handler to use instead of the base consumer if one of the provided ErrorResponses happens.
*
* Example
*
{@code
* 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()));
* }
* }
*
* @param errorResponses
* The {@link ErrorResponse ErrorResponses} to match
* @param handler
* The alternative handler
*
* @throws IllegalArgumentException
* If provided with null
*
* @return This ErrorHandler with the applied handler
*/
@Nonnull
public ErrorHandler handle(@Nonnull Collection errorResponses, @Nonnull Consumer handler)
{
Checks.notNull(handler, "Handler");
Checks.noneNull(errorResponses, "ErrorResponse");
return handle(ErrorResponseException.class, (it) -> errorResponses.contains(it.getErrorResponse()), handler);
}
/**
* Handle specific throwable types.
*
This will apply the specified handler if the throwable is of the specified type. The check is done using {@link Class#isInstance(Object)}.
*
* Example
*
{@code
* public static void logErrorResponse(RestAction action) {
* action.queue(null, new ErrorHandler()
* .handle(ErrorResponseException.class,
* (ex) -> System.out.println(ex.getErrorResponse())));
* }
* }
*
* @param clazz
* The throwable type
* @param handler
* The alternative handler
*
* @param
* The type
*
* @return This ErrorHandler with the applied handler
*/
@Nonnull
public ErrorHandler handle(@Nonnull Class clazz, @Nonnull Consumer handler)
{
Checks.notNull(clazz, "Class");
Checks.notNull(handler, "Handler");
return handle(clazz::isInstance, (ex) -> handler.accept(clazz.cast(ex)));
}
/**
* Handle specific throwable types.
*
This will apply the specified handler if the throwable is of the specified type. The check is done using {@link Class#isInstance(Object)}.
*
* Example
*
{@code
* public static void logErrorResponse(RestAction action) {
* action.queue(null, new ErrorHandler()
* .handle(ErrorResponseException.class,
* ErrorResponseException::isServerError,
* (ex) -> System.out.println(ex.getErrorCode() + ": " + ex.getMeaning())));
* }
* }
*
* @param clazz
* The throwable type
* @param condition
* Additional condition that must apply to use this handler
* @param handler
* The alternative handler
*
* @param
* The type
*
* @return This ErrorHandler with the applied handler
*/
@Nonnull
public ErrorHandler handle(@Nonnull Class clazz, @Nonnull Predicate condition, @Nonnull Consumer handler)
{
Checks.notNull(clazz, "Class");
Checks.notNull(handler, "Handler");
return handle(
(it) -> clazz.isInstance(it) && condition.test(clazz.cast(it)),
(ex) -> handler.accept(clazz.cast(ex)));
}
/**
* Handle specific throwable types.
*
This will apply the specified handler if the throwable is of the specified type. The check is done using {@link Class#isInstance(Object)}.
*
* Example
*
{@code
* public static void logErrorResponse(RestAction action) {
* action.queue(null, new ErrorHandler()
* .handle(Arrays.asList(Throwable.class),
* (ex) -> ex instanceof Error,
* (ex) -> ex.printStackTrace()));
* }
* }
*
* @param clazz
* The throwable types
* @param condition
* Additional condition that must apply to use this handler, or null to apply no additional condition
* @param handler
* The alternative handler
*
* @return This ErrorHandler with the applied handler
*/
@Nonnull
public ErrorHandler handle(@Nonnull Collection> clazz, @Nullable Predicate condition, @Nonnull Consumer handler)
{
Checks.noneNull(clazz, "Class");
Checks.notNull(handler, "Handler");
List> classes = new ArrayList<>(clazz);
Predicate check = (it) -> classes.stream().anyMatch(c -> c.isInstance(it)) && (condition == null || condition.test(it));
return handle(check, handler);
}
/**
* Handle specific conditions.
*
* Example
*
{@code
* public static void logErrorResponse(RestAction action) {
* action.queue(null, new ErrorHandler()
* .handle(
* (ex) -> !(ex instanceof ErrorResponseException),
* Throwable::printStackTrace));
* }
* }
*
* @param condition
* Condition that must apply to use this handler
* @param handler
* The alternative handler
*
* @return This ErrorHandler with the applied handler
*/
@Nonnull
public ErrorHandler handle(@Nonnull Predicate condition, @Nonnull Consumer handler)
{
Checks.notNull(condition, "Condition");
Checks.notNull(handler, "Handler");
cases.put(condition, handler);
return this;
}
@Override
public void accept(Throwable t)
{
for (Map.Entry, Consumer> entry : cases.entrySet())
{
Predicate condition = entry.getKey();
Consumer callback = entry.getValue();
if (condition.test(t))
{
callback.accept(t);
return;
}
}
base.accept(t);
}
}