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core: Add a way to map the output of argument parsers

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Zach Levis 2021-01-03 18:12:32 -08:00 • committed by Jason
parent 3be50956cc
commit 6b690811f1
3 changed files with 181 additions and 1 deletions
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60
cloud-core/src/main/java/cloud/commandframework/arguments/parser/ArgumentParseResult.java
View file

@ -26,6 +26,7 @@ package cloud.commandframework.arguments.parser;
import org.checkerframework.checker.nullness.qual.NonNull;
import java.util.Optional;
import java.util.function.Function;
/**
* Result of the parsing done by a {@link ArgumentParser}
@ -66,6 +67,26 @@ public abstract class ArgumentParseResult<T> {
*/
public abstract @NonNull Optional<T> getParsedValue();
/**
* If this result is successful, transform the output value.
*
* @param mapper the transformation
* @param <U> the result type
* @return a new result if successful, otherwise a failure
* @since 1.4.0
*/
public abstract <U> @NonNull ArgumentParseResult<U> mapParsedValue(Function<T, U> mapper);
/**
* If this result is successful, transform the output value, returning another parse result.
*
* @param mapper the transformation
* @param <U> the result type
* @return a new result if successful, otherwise a failure
* @since 1.4.0
*/
public abstract <U> @NonNull ArgumentParseResult<U> flatMapParsedValue(Function<T, ArgumentParseResult<U>> mapper);
/**
* Get the failure reason, if it exists
*
@ -73,6 +94,15 @@ public abstract class ArgumentParseResult<T> {
*/
public abstract @NonNull Optional<Throwable> getFailure();
/**
* If this result is a failure, transform the exception.
*
* @param mapper the exception transformation
* @return if this is a failure, a transformed result, otherwise this
* @since 1.4.0
*/
public abstract @NonNull ArgumentParseResult<T> mapFailure(Function<Throwable, Throwable> mapper);
private static final class ParseSuccess<T> extends ArgumentParseResult<T> {
@ -90,13 +120,27 @@ public abstract class ArgumentParseResult<T> {
return Optional.of(this.value);
}
@Override
public @NonNull <U> ArgumentParseResult<U> mapParsedValue(final Function<T, U> mapper) {
return new ParseSuccess<>(mapper.apply(this.value));
}
@Override
public @NonNull <U> ArgumentParseResult<U> flatMapParsedValue(final Function<T, ArgumentParseResult<U>> mapper) {
return mapper.apply(this.value);
}
@Override
public @NonNull Optional<Throwable> getFailure() {
return Optional.empty();
}
@Override
public @NonNull ArgumentParseResult<T> mapFailure(final Function<Throwable, Throwable> mapper) {
return this;
}
}
private static final class ParseFailure<T> extends ArgumentParseResult<T> {
@ -114,11 +158,27 @@ public abstract class ArgumentParseResult<T> {
return Optional.empty();
}
@Override
@SuppressWarnings("unchecked")
public @NonNull <U> ArgumentParseResult<U> mapParsedValue(final Function<T, U> mapper) {
return (ArgumentParseResult<U>) this;
}
@Override
@SuppressWarnings("unchecked")
public @NonNull <U> ArgumentParseResult<U> flatMapParsedValue(final Function<T, ArgumentParseResult<U>> mapper) {
return (ArgumentParseResult<U>) this;
}
@Override
public @NonNull Optional<Throwable> getFailure() {
return Optional.of(this.failure);
}
@Override
public @NonNull ArgumentParseResult<T> mapFailure(final Function<Throwable, Throwable> mapper) {
return new ParseFailure<>(mapper.apply(this.failure));
}
}
}

14
cloud-core/src/main/java/cloud/commandframework/arguments/parser/ArgumentParser.java
View file

@ -29,6 +29,9 @@ import org.checkerframework.checker.nullness.qual.NonNull;
import java.util.Collections;
import java.util.List;
import java.util.Queue;
import java.util.function.BiFunction;
import static java.util.Objects.requireNonNull;
/**
* Parser that parses strings into values of a specific type
@ -89,6 +92,17 @@ public interface ArgumentParser<C, T> {
return Collections.emptyList();
}
/**
* Create a derived argument parser preserving all properties of this parser, but converting the output type.
*
* @param mapper the mapper to apply
* @param <O> the result type
* @return a derived parser.
*/
default <O> @NonNull ArgumentParser<C, O> map(final BiFunction<CommandContext<C>, T, ArgumentParseResult<O>> mapper) {
return new MappedArgumentParser<>(this, requireNonNull(mapper, "mapper"));
}
/**
* Check whether or not this argument parser is context free. A context free
* parser will not use the provided command context, and so supports impromptu parsing

106
cloud-core/src/main/java/cloud/commandframework/arguments/parser/MappedArgumentParser.java Normal file
View file

@ -0,0 +1,106 @@
//
// MIT License
//
// Copyright (c) 2020 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.arguments.parser;
import cloud.commandframework.context.CommandContext;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
import java.util.List;
import java.util.Queue;
import java.util.function.BiFunction;
final class MappedArgumentParser<C, I, O> implements ArgumentParser<C, O> {
private final ArgumentParser<C, I> base;
private final BiFunction<CommandContext<C>, I, ArgumentParseResult<O>> mapper;
MappedArgumentParser(
final ArgumentParser<C, I> base,
final BiFunction<CommandContext<C>, I, ArgumentParseResult<O>> mapper
) {
this.base = base;
this.mapper = mapper;
}
@Override
public @NonNull ArgumentParseResult<@NonNull O> parse(
@NonNull final CommandContext<@NonNull C> commandContext,
@NonNull final Queue<@NonNull String> inputQueue
) {
final ArgumentParseResult<@NonNull I> baseResult = this.base.parse(commandContext, inputQueue);
return baseResult.flatMapParsedValue(value -> this.mapper.apply(commandContext, value));
}
@Override
public @NonNull List<@NonNull String> suggestions(
final @NonNull CommandContext<C> commandContext,
final @NonNull String input
) {
return this.base.suggestions(commandContext, input);
}
@Override
public @NonNull <O1> ArgumentParser<C, O1> map(final BiFunction<CommandContext<C>, O, ArgumentParseResult<O1>> mapper) {
return new MappedArgumentParser<>(
this.base,
(ctx, original) -> this.mapper.apply(ctx, original).flatMapParsedValue(value -> mapper.apply(ctx, value))
);
}
@Override
public boolean isContextFree() {
return this.base.isContextFree();
}
@Override
public int getRequestedArgumentCount() {
return this.base.getRequestedArgumentCount();
}
@Override
public int hashCode() {
return 31 + this.base.hashCode()
+ 7 * this.mapper.hashCode();
}
@Override
public boolean equals(final @Nullable Object other) {
if (!(other instanceof MappedArgumentParser<?, ?, ?>)) {
return false;
}
final MappedArgumentParser<?, ?, ?> that = (MappedArgumentParser<?, ?, ?>) other;
return this.base.equals(that.base)
&& this.mapper.equals(that.mapper);
}
@Override
public String toString() {
return "MappedArgumentParser{"
+ "base=" + this.base + ','
+ "mapper=" + this.mapper + '}';
}
}