net.dv8tion.jda.api.requests.restaction.pagination.PaginationAction Maven / Gradle / Ivy
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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.requests.restaction.pagination;
import net.dv8tion.jda.api.requests.RestAction;
import net.dv8tion.jda.api.utils.Procedure;
import net.dv8tion.jda.internal.requests.RestActionImpl;
import net.dv8tion.jda.internal.utils.Checks;
import org.jetbrains.annotations.Blocking;
import org.jetbrains.annotations.Unmodifiable;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.*;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;
import java.util.function.BooleanSupplier;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
/**
* {@link net.dv8tion.jda.api.requests.RestAction RestAction} specification used
* to retrieve entities for paginated endpoints (before, after, limit).
*
Note that this implementation is not considered thread-safe as modifications to the cache are not done
* with a lock. Calling methods on this class from multiple threads is not recommended.
*
* Examples
*
* /**
* * Retrieves messages until the specified limit is reached. The messages will be limited after being filtered by the user.
* * If the user hasn't sent enough messages this will go through all messages so it is recommended to add an additional end condition.
* */
* public static {@literal List} getMessagesByUser(MessageChannel channel, User user, int limit)
* {
* MessagePaginationAction action = channel.getIterableHistory();
* Stream{@literal } messageStream = action.stream()
* .limit(limit * 2) // used to limit amount of messages to check, if user hasn't sent enough messages it would go on forever
* .filter( message{@literal ->} message.getAuthor().equals(user) )
* .limit(limit); // limit on filtered stream will be checked independently from previous limit
* return messageStream.collect(Collectors.toList());
* }
*
*
*
* /**
* * Iterates messages in an async stream and stops once the limit has been reached.
* */
* public static void onEachMessageAsync(MessageChannel channel, {@literal Consumer} consumer, int limit)
* {
* if (limit{@literal <} 1)
* return;
* MessagePaginationAction action = channel.getIterableHistory();
* AtomicInteger counter = new AtomicInteger(limit);
* action.forEachAsync( (message){@literal ->}
* {
* consumer.accept(message);
* // if false the iteration is terminated; else it continues
* return counter.decrementAndGet() == 0;
* });
* }
*
*
* @param
* The current implementation used as chaining return value
* @param
* The type of entity to paginate
*
* @since 3.1
*/
public interface PaginationAction> extends RestAction<@Unmodifiable List>, Iterable
{
/**
* Skips past the specified ID for successive requests.
* This will reset the {@link #getLast()} entity and cause a {@link NoSuchElementException} to be thrown
* when attempting to get the last entity until a new retrieve action has been done.
*
If cache is disabled this can be set to an arbitrary value irrelevant of the current last.
* Set this to {@code 0} to start from the most recent message.
*
* Fails if cache is enabled and the target id is newer than the current last id {@literal (id > last)}.
*
*
Example
*
{@code
* public MessagePaginationAction getOlderThan(MessageChannel channel, long time) {
* final long timestamp = TimeUtil.getDiscordTimestamp(time);
* final MessagePaginationAction paginator = channel.getIterableHistory();
* return paginator.skipTo(timestamp);
* }
*
* getOlderThan(channel, System.currentTimeMillis() - TimeUnit.DAYS.toMillis(14))
* .forEachAsync((message) -> {
* boolean empty = message.getContentRaw().isEmpty();
* if (!empty)
* System.out.printf("%#s%n", message); // means: print display content
* return !empty; // means: continue if not empty
* });
* }
*
* @param id
* The snowflake ID to skip before, this is exclusive rather than inclusive
*
* @throws IllegalArgumentException
* If cache is enabled, and you are attempting to skip forward in time {@literal (id > last)}
*
* @return The current PaginationAction for chaining convenience
*
* @see java.util.concurrent.TimeUnit
* @see net.dv8tion.jda.api.utils.TimeUtil
*/
@Nonnull
M skipTo(long id);
/**
* The current iteration anchor used for pagination.
*
This is updated by each retrieve action.
*
* @return The current iteration anchor
*
* @see #skipTo(long) Use skipTo(anchor) to change this
*/
long getLastKey();
@Nonnull
@Override
M setCheck(@Nullable BooleanSupplier checks);
@Nonnull
@Override
M timeout(long timeout, @Nonnull TimeUnit unit);
@Nonnull
@Override
M deadline(long timestamp);
/**
* The supported {@link PaginationOrder PaginationOrders} for this pagination action.
*
All enum values that are not returned will cause a throw for {@link #order(PaginationOrder)}.
*
* Most pagination endpoints only support a single order, however some endpoints such as message pagination supports both.
*
* @return {@link EnumSet} of {@link PaginationOrder} (Modifying this set does not affect this class)
*/
@Nonnull
default EnumSet getSupportedOrders()
{
return EnumSet.allOf(PaginationOrder.class);
}
/**
* The current iteration order.
*
This defaults to {@link PaginationOrder#BACKWARD}, meaning most recent first, for most pagination endpoints.
*
* @return The {@link PaginationOrder}
*
* @see #order(PaginationOrder)
*/
@Nonnull
PaginationOrder getOrder();
/**
* Configure the {@link PaginationOrder} of this pagination action.
*
* You can only supply supported orders, see {@link #getSupportedOrders()}.
*
* @param order
* The pagination order
*
* @throws IllegalArgumentException
* If the provided pagination order is null or unsupported
* @throws IllegalStateException
* If this pagination action has already been used to retrieve entities
*
* @return The current PaginationAction implementation instance
*
* @see #getSupportedOrders()
* @see #reverse()
*/
@Nonnull
M order(@Nonnull PaginationOrder order);
/**
* Flips the {@link #order(PaginationOrder)} of this pagination action.
*
* @throws IllegalArgumentException
* If this pagination action does not support the reversed order
*
* @return The current PaginationAction implementation instance
*/
@Nonnull
default M reverse()
{
if (getOrder() == PaginationOrder.BACKWARD)
return order(PaginationOrder.FORWARD);
return order(PaginationOrder.BACKWARD);
}
/**
* The current amount of cached entities for this PaginationAction
*
* @return int size of currently cached entities
*/
int cacheSize();
/**
* Whether the cache of this PaginationAction is empty.
*
Logically equivalent to {@code cacheSize() == 0}.
*
* @return True, if no entities have been retrieved yet.
*/
boolean isEmpty();
/**
* The currently cached entities of recent execution tasks.
*
Every {@link net.dv8tion.jda.api.requests.RestAction RestAction} success
* adds to this List. (Thread-Safe due to {@link java.util.concurrent.CopyOnWriteArrayList CopyOnWriteArrayList})
*
*
This does not contain all entities for the paginated endpoint unless the pagination has reached an end!
*
It only contains those entities which already have been retrieved.
*
* @return Immutable {@link java.util.List List} containing all currently cached entities for this PaginationAction
*/
@Nonnull
@Unmodifiable
List getCached();
/**
* The most recent entity retrieved by this PaginationAction instance
*
* @throws java.util.NoSuchElementException
* If no entities have been retrieved yet (see {@link #isEmpty()})
*
* @return The most recent cached entity
*/
@Nonnull
T getLast();
/**
* The first cached entity retrieved by this PaginationAction instance
*
* @throws java.util.NoSuchElementException
* If no entities have been retrieved yet (see {@link #isEmpty()})
*
* @return The very first cached entity
*/
@Nonnull
T getFirst();
/**
* Sets the limit that should be used in the next RestAction completion
* call.
*
* The specified limit may not be below the {@link #getMinLimit() Minimum Limit} nor above
* the {@link #getMaxLimit() Maximum Limit}. Unless these limits are specifically omitted. (See documentation of methods)
*
*
This limit represents how many entities will be retrieved per request and
* NOT the maximum amount of entities that should be retrieved for iteration/sequencing.
*
{@code action.limit(50).complete()}
*
is not the same as
*
{@code action.stream().limit(50).collect(collector)}
*
*
* @param limit
* The limit to use
*
* @throws java.lang.IllegalArgumentException
* If the provided limit is out of range
*
* @return The current PaginationAction implementation instance
*/
@Nonnull
M limit(final int limit);
/**
* Whether already retrieved entities should be stored
* within the internal cache. All cached entities will be
* available from {@link #getCached()}.
* Default: true
*
This being disabled allows unused entities to be removed from
* the memory heap by the garbage collector. If this is enabled this will not
* take place until all references to this PaginationAction have been cleared.
*
* @param enableCache
* Whether to enable entity cache
*
* @return The current PaginationAction implementation instance
*/
@Nonnull
M cache(final boolean enableCache);
/**
* Whether retrieved entities are stored within an
* internal cache. If this is {@code false} entities
* retrieved by the iterator or a call to a {@link net.dv8tion.jda.api.requests.RestAction RestAction}
* terminal operation will not be retrievable from {@link #getCached()}.
*
This being disabled allows unused entities to be removed from
* the memory heap by the garbage collector. If this is enabled this will not
* take place until all references to this PaginationAction have been cleared.
*
* @return True, If entities will be cached.
*/
boolean isCacheEnabled();
/**
* The maximum limit that can be used for this PaginationAction
*
Limits provided to {@link #limit(int)} must not be greater
* than the returned value.
*
If no maximum limit is used this will return {@code 0}.
* That means there is no upper border for limiting this PaginationAction
*
* @return The maximum limit
*/
int getMaxLimit();
/**
* The minimum limit that can be used for this PaginationAction
*
Limits provided to {@link #limit(int)} must not be less
* than the returned value.
*
If no minimum limit is used this will return {@code 0}.
* That means there is no lower border for limiting this PaginationAction
*
* @return The minimum limit
*/
int getMinLimit();
/**
* The currently used limit.
*
If this PaginationAction does not use limitation
* this will return {@code 0}
*
* @return limit
*/
int getLimit();
/**
* Retrieves elements while the specified condition is met.
*
* @param rule
* The rule which must be fulfilled for an element to be added,
* returns false to discard the element and finish the task
*
* @throws IllegalArgumentException
* If the provided rule is {@code null}
*
* @return {@link CompletableFuture} - Type: {@link List List}
*
Future representing the fetch task, the list will be sorted most recent to oldest
*
* @see #takeWhileAsync(int, Predicate)
* @see #takeUntilAsync(Predicate)
*/
@Nonnull
default CompletableFuture> takeWhileAsync(@Nonnull final Predicate rule)
{
Checks.notNull(rule, "Rule");
return takeUntilAsync(rule.negate());
}
/**
* Retrieves elements while the specified condition is met.
*
* @param limit
* The maximum amount of elements to collect or {@code 0} for no limit
* @param rule
* The rule which must be fulfilled for an element to be added,
* returns false to discard the element and finish the task
*
* @throws IllegalArgumentException
* If the provided rule is {@code null} or the limit is negative
*
* @return {@link CompletableFuture} - Type: {@link List List}
*
Future representing the fetch task, the list will be sorted most recent to oldest
*
* @see #takeWhileAsync(Predicate)
* @see #takeUntilAsync(int, Predicate)
*/
@Nonnull
default CompletableFuture> takeWhileAsync(int limit, @Nonnull final Predicate rule)
{
Checks.notNull(rule, "Rule");
return takeUntilAsync(limit, rule.negate());
}
/**
* Retrieves elements until the specified condition is met.
*
* @param rule
* The rule which must be fulfilled for an element to be discarded,
* returns true to discard the element and finish the task
*
* @throws IllegalArgumentException
* If the provided rule is {@code null}
*
* @return {@link CompletableFuture} - Type: {@link List List}
*
Future representing the fetch task, the list will be sorted most recent to oldest
*
* @see #takeWhileAsync(Predicate)
* @see #takeUntilAsync(int, Predicate)
*/
@Nonnull
default CompletableFuture> takeUntilAsync(@Nonnull final Predicate rule)
{
return takeUntilAsync(0, rule);
}
/**
* Retrieves elements until the specified condition is met.
*
* @param limit
* The maximum amount of elements to collect or {@code 0} for no limit
* @param rule
* The rule which must be fulfilled for an element to be discarded,
* returns true to discard the element and finish the task
*
* @throws IllegalArgumentException
* If the provided rule is {@code null} or the limit is negative
*
* @return {@link CompletableFuture} - Type: {@link List List}
*
Future representing the fetch task, the list will be sorted most recent to oldest
*
* @see #takeWhileAsync(Predicate)
* @see #takeUntilAsync(int, Predicate)
*/
@Nonnull
default CompletableFuture> takeUntilAsync(int limit, @Nonnull final Predicate rule)
{
Checks.notNull(rule, "Rule");
Checks.notNegative(limit, "Limit");
List result = new ArrayList<>();
CompletableFuture> future = new CompletableFuture<>();
CompletableFuture handle = forEachAsync((element) -> {
if (rule.test(element))
return false;
result.add(element);
return limit == 0 || limit > result.size();
});
handle.whenComplete((r, t) -> {
if (t != null)
future.completeExceptionally(t);
else
future.complete(result);
});
return future;
}
/**
* Convenience method to retrieve an amount of entities from this pagination action.
*
This also includes already cached entities similar to {@link #forEachAsync(Procedure)}.
*
* @param amount
* The maximum amount to retrieve
*
* @return {@link java.util.concurrent.CompletableFuture CompletableFuture} - Type: {@link java.util.List List}
*
* @see #forEachAsync(Procedure)
*/
@Nonnull
CompletableFuture> takeAsync(int amount);
/**
* Convenience method to retrieve an amount of entities from this pagination action.
*
Unlike {@link #takeAsync(int)} this does not include already cached entities.
*
* @param amount
* The maximum amount to retrieve
*
* @return {@link java.util.concurrent.CompletableFuture CompletableFuture} - Type: {@link java.util.List List}
*
* @see #forEachRemainingAsync(Procedure)
*/
@Nonnull
CompletableFuture> takeRemainingAsync(int amount);
/**
* Iterates over all entities until the provided action returns {@code false}!
*
This operation is different from {@link #forEach(Consumer)} as it
* uses successive {@link #queue()} tasks to iterate each entity in callback threads instead of
* the calling active thread.
* This means that this method fully works on different threads to retrieve new entities.
* This iteration will include already cached entities, in order to exclude cached
* entities use {@link #forEachRemainingAsync(Procedure)}
*
*
Example
*
{@code
* //deletes messages until it finds a user that is still in guild
* public void cleanupMessages(MessagePaginationAction action)
* {
* action.forEachAsync( (message) ->
* {
* Guild guild = message.getGuild();
* if (!guild.isMember(message.getAuthor()))
* message.delete().queue();
* else
* return false;
* return true;
* });
* }
* }
*
* @param action
* {@link net.dv8tion.jda.api.utils.Procedure Procedure} returning {@code true} if iteration should continue!
*
* @throws java.lang.IllegalArgumentException
* If the provided Procedure is {@code null}
*
* @return {@link java.util.concurrent.Future Future} that can be cancelled to stop iteration from outside!
*/
@Nonnull
default CompletableFuture forEachAsync(@Nonnull final Procedure action)
{
return forEachAsync(action, RestActionImpl.getDefaultFailure());
}
/**
* Iterates over all entities until the provided action returns {@code false}!
*
This operation is different from {@link #forEach(Consumer)} as it
* uses successive {@link #queue()} tasks to iterate each entity in callback threads instead of
* the calling active thread.
* This means that this method fully works on different threads to retrieve new entities.
*
* This iteration will include already cached entities, in order to exclude cached
* entities use {@link #forEachRemainingAsync(Procedure, Consumer)}
*
*
Example
*
{@code
* //deletes messages until it finds a user that is still in guild
* public void cleanupMessages(MessagePaginationAction action)
* {
* action.forEachAsync( (message) ->
* {
* Guild guild = message.getGuild();
* if (!guild.isMember(message.getAuthor()))
* message.delete().queue();
* else
* return false;
* return true;
* }, Throwable::printStackTrace);
* }
* }
*
* @param action
* {@link net.dv8tion.jda.api.utils.Procedure Procedure} returning {@code true} if iteration should continue!
* @param failure
* {@link java.util.function.Consumer Consumer} that should handle any throwables from the action
*
* @throws java.lang.IllegalArgumentException
* If the provided Procedure or the failure Consumer is {@code null}
*
* @return {@link java.util.concurrent.Future Future} that can be cancelled to stop iteration from outside!
*/
@Nonnull
CompletableFuture forEachAsync(@Nonnull final Procedure action, @Nonnull final Consumer failure);
/**
* Iterates over all remaining entities until the provided action returns {@code false}!
*
This operation is different from {@link #forEachRemaining(Procedure)} as it
* uses successive {@link #queue()} tasks to iterate each entity in callback threads instead of
* the calling active thread.
* This means that this method fully works on different threads to retrieve new entities.
*
* This iteration will exclude already cached entities, in order to include cached
* entities use {@link #forEachAsync(Procedure)}
*
*
Example
*
{@code
* //deletes messages until it finds a user that is still in guild
* public void cleanupMessages(MessagePaginationAction action)
* {
* action.forEachRemainingAsync( (message) ->
* {
* Guild guild = message.getGuild();
* if (!guild.isMember(message.getAuthor()))
* message.delete().queue();
* else
* return false;
* return true;
* });
* }
* }
*
* @param action
* {@link net.dv8tion.jda.api.utils.Procedure Procedure} returning {@code true} if iteration should continue!
*
* @throws java.lang.IllegalArgumentException
* If the provided Procedure is {@code null}
*
* @return {@link java.util.concurrent.Future Future} that can be cancelled to stop iteration from outside!
*/
@Nonnull
default CompletableFuture forEachRemainingAsync(@Nonnull final Procedure action)
{
return forEachRemainingAsync(action, RestActionImpl.getDefaultFailure());
}
/**
* Iterates over all remaining entities until the provided action returns {@code false}!
*
This operation is different from {@link #forEachRemaining(Procedure)} as it
* uses successive {@link #queue()} tasks to iterate each entity in callback threads instead of
* the calling active thread.
* This means that this method fully works on different threads to retrieve new entities.
*
* This iteration will exclude already cached entities, in order to include cached
* entities use {@link #forEachAsync(Procedure, Consumer)}
*
*
Example
*
{@code
* //deletes messages until it finds a user that is still in guild
* public void cleanupMessages(MessagePaginationAction action)
* {
* action.forEachRemainingAsync( (message) ->
* {
* Guild guild = message.getGuild();
* if (!guild.isMember(message.getAuthor()))
* message.delete().queue();
* else
* return false;
* return true;
* }, Throwable::printStackTrace);
* }
* }
*
* @param action
* {@link net.dv8tion.jda.api.utils.Procedure Procedure} returning {@code true} if iteration should continue!
* @param failure
* {@link java.util.function.Consumer Consumer} that should handle any throwables from the action
*
* @throws java.lang.IllegalArgumentException
* If the provided Procedure or the failure Consumer is {@code null}
*
* @return {@link java.util.concurrent.Future Future} that can be cancelled to stop iteration from outside!
*/
@Nonnull
CompletableFuture forEachRemainingAsync(@Nonnull final Procedure action, @Nonnull final Consumer failure);
/**
* Iterates over all remaining entities until the provided action returns {@code false}!
*
Skipping past already cached entities to iterate all remaining entities of this PaginationAction.
*
* This is a blocking operation that might take a while to complete
*
* @param action
* The {@link net.dv8tion.jda.api.utils.Procedure Procedure}
* which should return {@code true} to continue iterating
*/
@Blocking
void forEachRemaining(@Nonnull final Procedure action);
@Override
@Blocking
default Spliterator spliterator()
{
return Spliterators.spliteratorUnknownSize(iterator(), Spliterator.IMMUTABLE);
}
/**
* A sequential {@link java.util.stream.Stream Stream} with this PaginationAction as its source.
*
* @return a sequential {@code Stream} over the elements in this PaginationAction
*/
@Nonnull
@Blocking
default Stream stream()
{
return StreamSupport.stream(spliterator(), false);
}
/**
* Returns a possibly parallel {@link java.util.stream.Stream Stream} with this PaginationAction as its
* source. It is allowable for this method to return a sequential stream.
*
* @return a sequential {@code Stream} over the elements in this PaginationAction
*/
@Nonnull
@Blocking
default Stream parallelStream()
{
return StreamSupport.stream(spliterator(), true);
}
/**
* {@link PaginationIterator PaginationIterator}
* that will iterate over all entities for this PaginationAction.
*
* @return new PaginationIterator
*/
@Nonnull
@Override
@Blocking
PaginationIterator iterator();
/**
* Defines the pagination order for a pagination endpoint.
*/
enum PaginationOrder
{
/**
* Iterates backwards in time, listing the most recent entities first.
*/
BACKWARD("before"),
/**
* Iterates forward in time, listing the oldest entities first.
*/
FORWARD("after");
private final String key;
PaginationOrder(String key)
{
this.key = key;
}
/**
* The API query parameter key
*
* @return The query key
*/
@Nonnull
public String getKey()
{
return key;
}
}
/**
* Iterator implementation for a {@link PaginationAction PaginationAction}.
*
This iterator will first iterate over all currently cached entities and continue to retrieve new entities
* as needed.
*
* To retrieve new entities after reaching the end of the current cache, this iterator will
* request a List of new entities through a call of {@link net.dv8tion.jda.api.requests.RestAction#complete() RestAction.complete()}.
*
It is recommended to use the highest possible limit for this task. (see {@link #limit(int)})
*/
class PaginationIterator implements Iterator
{
protected Queue items;
protected final Supplier> supply;
public PaginationIterator(Collection queue, Supplier> supply)
{
this.items = new LinkedList<>(queue);
this.supply = supply;
}
@Override
public boolean hasNext()
{
if (items == null)
return false;
if (!hitEnd())
return true;
if (items.addAll(supply.get()))
return true;
// null indicates that the real end has been reached
items = null;
return false;
}
@Override
public E next()
{
if (!hasNext())
throw new NoSuchElementException("Reached End of pagination task!");
return items.poll();
}
protected boolean hitEnd()
{
return items.isEmpty();
}
}
}