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Java wrapper for the popular chat & VOIP service: Discord https://discord.com
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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.internal.requests.restaction.pagination;
import net.dv8tion.jda.api.JDA;
import net.dv8tion.jda.api.requests.Route;
import net.dv8tion.jda.api.requests.restaction.pagination.PaginationAction;
import net.dv8tion.jda.api.utils.Procedure;
import net.dv8tion.jda.internal.requests.RestActionImpl;
import net.dv8tion.jda.internal.utils.Checks;
import javax.annotation.Nonnull;
import java.util.*;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.BiFunction;
import java.util.function.BooleanSupplier;
import java.util.function.Consumer;
public abstract class PaginationActionImpl>
extends RestActionImpl>
implements PaginationAction
{
protected final List cached = new CopyOnWriteArrayList<>();
protected final int maxLimit;
protected final int minLimit;
protected final AtomicInteger limit;
protected PaginationOrder order = PaginationOrder.BACKWARD;
protected volatile long iteratorIndex = 0;
protected volatile long lastKey = 0;
protected volatile T last = null;
protected volatile boolean useCache = true;
/**
* Creates a new PaginationAction instance
*
* @param api
* The current JDA instance
* @param route
* The base route
* @param maxLimit
* The inclusive maximum limit that can be used in {@link #limit(int)}
* @param minLimit
* The inclusive minimum limit that can be used in {@link #limit(int)}
* @param initialLimit
* The initial limit to use on the pagination endpoint
*/
public PaginationActionImpl(JDA api, Route.CompiledRoute route, int minLimit, int maxLimit, int initialLimit)
{
super(api, route);
this.maxLimit = maxLimit;
this.minLimit = minLimit;
this.limit = new AtomicInteger(initialLimit);
}
/**
* Creates a new PaginationAction instance
*
This is used for PaginationActions that should not deal with
* {@link #limit(int)}
*
* @param api
* The current JDA instance
*/
public PaginationActionImpl(JDA api)
{
super(api, null);
this.maxLimit = 0;
this.minLimit = 0;
this.limit = new AtomicInteger(0);
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M skipTo(long id)
{
if (!cached.isEmpty())
{
int cmp = Long.compareUnsigned(this.lastKey, id);
if (cmp < 0) // old - new < 0 => old < new
throw new IllegalArgumentException("Cannot jump to that id, it is newer than the current oldest element.");
}
if (this.lastKey != id)
this.last = null;
this.iteratorIndex = id;
this.lastKey = id;
return (M) this;
}
@Override
public long getLastKey()
{
return lastKey;
}
@Nonnull
@Override
public PaginationOrder getOrder()
{
return order;
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M order(@Nonnull PaginationAction.PaginationOrder order)
{
Checks.notNull(order, "PaginationOrder");
if (order != this.order)
{
if (!isEmpty())
throw new IllegalStateException("Cannot change pagination order after retrieving.");
if (!getSupportedOrders().contains(order))
throw new IllegalArgumentException("Cannot use PaginationOrder." + order + " for this pagination endpoint.");
}
this.order = order;
return (M) this;
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M setCheck(BooleanSupplier checks)
{
return (M) super.setCheck(checks);
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M timeout(long timeout, @Nonnull TimeUnit unit)
{
return (M) super.timeout(timeout, unit);
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M deadline(long timestamp)
{
return (M) super.deadline(timestamp);
}
@Override
public int cacheSize()
{
return cached.size();
}
@Override
public boolean isEmpty()
{
return cached.isEmpty();
}
@Nonnull
@Override
public List getCached()
{
return Collections.unmodifiableList(cached);
}
@Nonnull
@Override
public T getLast()
{
final T last = this.last;
if (last == null)
throw new NoSuchElementException("No entities have been retrieved yet.");
return last;
}
@Nonnull
@Override
public T getFirst()
{
if (cached.isEmpty())
throw new NoSuchElementException("No entities have been retrieved yet.");
return cached.get(0);
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M limit(final int limit)
{
Checks.check(maxLimit == 0 || limit <= maxLimit, "Limit must not exceed %d!", maxLimit);
Checks.check(minLimit == 0 || limit >= minLimit, "Limit must be greater or equal to %d", minLimit);
this.limit.set(limit);
return (M) this;
}
@Nonnull
@Override
@SuppressWarnings("unchecked")
public M cache(final boolean enableCache)
{
this.useCache = enableCache;
return (M) this;
}
@Override
public boolean isCacheEnabled()
{
return useCache;
}
@Override
public final int getMaxLimit()
{
return maxLimit;
}
@Override
public final int getMinLimit()
{
return minLimit;
}
@Override
public final int getLimit()
{
return limit.get();
}
@Nonnull
@Override
public CompletableFuture> takeAsync(int amount)
{
return takeAsync0(amount, (task, list) -> forEachAsync(val ->
{
list.add(val);
return list.size() < amount;
}, task::completeExceptionally));
}
@Nonnull
@Override
public CompletableFuture> takeRemainingAsync(int amount)
{
return takeAsync0(amount, (task, list) -> forEachRemainingAsync(val ->
{
list.add(val);
return list.size() < amount;
}, task::completeExceptionally));
}
private CompletableFuture> takeAsync0(int amount, BiFunction, List, CompletableFuture> converter)
{
CompletableFuture> task = new CompletableFuture<>();
List list = new ArrayList<>(amount);
CompletableFuture promise = converter.apply(task, list);
promise.thenRun(() -> task.complete(list));
return task;
}
@Nonnull
@Override
public PaginationIterator iterator()
{
return new PaginationIterator<>(cached, this::getNextChunk);
}
@Nonnull
@Override
public CompletableFuture forEachAsync(@Nonnull final Procedure action, @Nonnull final Consumer failure)
{
Checks.notNull(action, "Procedure");
Checks.notNull(failure, "Failure Consumer");
final CompletableFuture task = new CompletableFuture<>();
final Consumer> acceptor = new ChainedConsumer(task, action, (throwable) ->
{
task.completeExceptionally(throwable);
failure.accept(throwable);
});
try
{
acceptor.accept(cached);
}
catch (Exception ex)
{
failure.accept(ex);
task.completeExceptionally(ex);
}
return task;
}
@Nonnull
@Override
public CompletableFuture forEachRemainingAsync(@Nonnull final Procedure action, @Nonnull final Consumer failure)
{
Checks.notNull(action, "Procedure");
Checks.notNull(failure, "Failure Consumer");
final CompletableFuture task = new CompletableFuture<>();
final Consumer> acceptor = new ChainedConsumer(task, action, (throwable) ->
{
task.completeExceptionally(throwable);
failure.accept(throwable);
});
try
{
acceptor.accept(getRemainingCache());
}
catch (Exception ex)
{
failure.accept(ex);
task.completeExceptionally(ex);
}
return task;
}
@Override
public void forEachRemaining(@Nonnull final Procedure action)
{
Checks.notNull(action, "Procedure");
Queue queue = new LinkedList<>();
while (queue.addAll(getNextChunk()))
{
while (!queue.isEmpty())
{
T it = queue.poll();
if (!action.execute(it))
{
// set the iterator index for next call of remaining
updateIndex(it);
return;
}
}
}
}
// Introduced for paginating archived threads, because two endpoints require a different request parameter value format.
// May become more useful if discord introduces more pagination endpoints not using ids.
// Check ThreadChannelPaginationActionImpl
// Background of #getPaginationLastEvaluatedKey:
// Archived thread channel pagination (example: TextChannel#retrieveArchivedPublicThreadChannels) would throw an exception,
// where Discord complained about receiving a snowflake instead of an ISO8601 date.
// The snowflake originated from this class (creating initial & subsequent requests),
// while the correct value was set in ThreadChannelPaginationActionImpl for the initial request
// and appended as a second value for subsequent requests.
// However, withQueryParams is a simple string append and Discord only reads the first parameter.
// If you debugged, you would see some duplicated fields on the compiled route.
// The fix here is to let the implementor supply the "last" string value, which could be anything,
// while the default implementation still would provide snowflakes
@Nonnull
protected String getPaginationLastEvaluatedKey(long lastId, T last)
{
return Long.toUnsignedString(lastId);
}
@Override
protected Route.CompiledRoute finalizeRoute()
{
Route.CompiledRoute route = super.finalizeRoute();
final String limit = String.valueOf(this.getLimit());
final long localLastKey = this.lastKey;
route = route.withQueryParams("limit", limit);
if (localLastKey != 0)
route = route.withQueryParams(order.getKey(), getPaginationLastEvaluatedKey(localLastKey, this.last));
else if (order == PaginationOrder.FORWARD)
route = route.withQueryParams("after", getPaginationLastEvaluatedKey(0, this.last));
return route;
}
protected List getRemainingCache()
{
int index = getIteratorIndex();
if (useCache && index > -1 && index < cached.size())
return cached.subList(index, cached.size());
return Collections.emptyList();
}
public List getNextChunk()
{
List list = getRemainingCache();
if (!list.isEmpty())
return list;
final int current = limit.getAndSet(getMaxLimit());
list = complete();
limit.set(current);
return list;
}
protected abstract long getKey(T it);
protected int getIteratorIndex()
{
for (int i = 0; i < cached.size(); i++)
{
if (getKey(cached.get(i)) == iteratorIndex)
return i + 1;
}
return -1;
}
protected void updateIndex(T it)
{
long key = getKey(it);
iteratorIndex = key;
if (!useCache)
{
lastKey = key;
last = it;
}
}
protected class ChainedConsumer implements Consumer>
{
protected final CompletableFuture task;
protected final Procedure action;
protected final Consumer throwableConsumer;
protected boolean initial = true;
protected ChainedConsumer(final CompletableFuture task, final Procedure action,
final Consumer throwableConsumer)
{
this.task = task;
this.action = action;
this.throwableConsumer = throwableConsumer;
}
@Override
public void accept(final List list)
{
if (list.isEmpty() && !initial)
{
task.complete(null);
return;
}
initial = false;
T previous = null;
for (T it : list)
{
if (task.isCancelled())
{
if (previous != null)
updateIndex(previous);
return;
}
if (action.execute(it))
{
previous = it;
continue;
}
// set the iterator index for next call of remaining
updateIndex(it);
task.complete(null);
return;
}
final int currentLimit = limit.getAndSet(maxLimit);
queue(this, throwableConsumer);
limit.set(currentLimit);
}
}
}