cloud.commandframework.execution.CommandExecutionHandler Maven / Gradle / Ivy
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//
// MIT License
//
// Copyright (c) 2022 Alexander Söderberg & Contributors
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
package cloud.commandframework.execution;
import cloud.commandframework.Command;
import cloud.commandframework.context.CommandContext;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import org.apiguardian.api.API;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Handler that is invoked whenever a {@link Command} is executed
* by a command sender
*
* @param Command sender type
*/
@FunctionalInterface
@API(status = API.Status.STABLE)
public interface CommandExecutionHandler {
/**
* Returns a {@link CommandExecutionHandler} that does nothing (no-op).
*
* @param Command sender type
* @return command execution handler that does nothing
* @since 1.7.0
*/
@API(status = API.Status.STABLE, since = "1.7.0")
static @NonNull CommandExecutionHandler noOpCommandExecutionHandler() {
return new NullCommandExecutionHandler<>();
}
/**
* Returns a {@link CommandExecutionHandler} that delegates the given
* {@code handlers} in sequence.
*
* If any handler in the chain throws an exception, then no subsequent
* handlers will be invoked.
*
* @param handlers The handlers to delegate to
* @param Command sender type
* @return multicast-delegate command execution handler
* @since 1.7.0
*/
@API(status = API.Status.STABLE, since = "1.7.0")
static @NonNull CommandExecutionHandler delegatingExecutionHandler(
final List> handlers
) {
return new MulticastDelegateFutureCommandExecutionHandler<>(handlers);
}
/**
* Handle command execution
*
* @param commandContext Command context
*/
void execute(@NonNull CommandContext commandContext);
/**
* Handle command execution
*
* @param commandContext Command context
* @return future that completes when the command has finished execution
* @since 1.6.0
*/
@API(status = API.Status.STABLE, since = "1.6.0")
default CompletableFuture<@Nullable Void> executeFuture(@NonNull CommandContext commandContext) {
final CompletableFuture future = new CompletableFuture<>();
try {
this.execute(commandContext);
/* The command executed successfully */
future.complete(null);
} catch (final Throwable throwable) {
future.completeExceptionally(throwable);
}
return future;
}
/**
* Command execution handler that does nothing
*
* @param Command sender type
*/
@API(status = API.Status.INTERNAL, consumers = "cloud.commandframework.*")
class NullCommandExecutionHandler implements CommandExecutionHandler {
@Override
public void execute(final @NonNull CommandContext commandContext) {
}
}
/**
* Handler that is invoked whenever a {@link Command} is executed
* by a command sender
*
* @param Command sender type
* @since 1.6.0
*/
@FunctionalInterface
@API(status = API.Status.STABLE, since = "1.6.0")
interface FutureCommandExecutionHandler extends CommandExecutionHandler {
@Override
@SuppressWarnings("FunctionalInterfaceMethodChanged")
default void execute(
@NonNull CommandContext commandContext
) {
}
@Override
CompletableFuture<@Nullable Void> executeFuture(
@NonNull CommandContext commandContext
);
}
/**
* Delegates to other handlers.
*
* @param Command sender type
* @see #delegatingExecutionHandler(List)
* @since 1.7.0
*/
@API(status = API.Status.INTERNAL, consumers = "cloud.commandframework.*", since = "1.7.0")
final class MulticastDelegateFutureCommandExecutionHandler implements FutureCommandExecutionHandler {
private final List> handlers;
private MulticastDelegateFutureCommandExecutionHandler(
final @NonNull List<@NonNull CommandExecutionHandler> handlers
) {
this.handlers = Collections.unmodifiableList(handlers);
}
@Override
public CompletableFuture<@Nullable Void> executeFuture(
@NonNull final CommandContext commandContext
) {
@MonotonicNonNull CompletableFuture<@Nullable Void> composedHandler = null;
if (this.handlers.isEmpty()) {
composedHandler = CompletableFuture.completedFuture(null);
} else {
for (final CommandExecutionHandler handler : this.handlers) {
if (composedHandler == null) {
composedHandler = handler.executeFuture(commandContext);
} else {
composedHandler = composedHandler.thenCompose(
ignore -> handler.executeFuture(commandContext)
);
}
}
}
return composedHandler;
}
}
}