133 lines
3.5 KiB
Java
133 lines
3.5 KiB
Java
package cc.fascinated.common;
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import lombok.NonNull;
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import net.jodah.expiringmap.ExpirationPolicy;
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import net.jodah.expiringmap.ExpiringMap;
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import java.util.Iterator;
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import java.util.Set;
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import java.util.concurrent.TimeUnit;
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import java.util.function.Consumer;
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/**
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* A simple set that expires elements after a certain
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* amount of time, utilizing the {@link ExpiringMap} library.
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*
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* @param <T> The type of element to store within this set
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* @author Braydon
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*/
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public final class ExpiringSet<T> implements Iterable<T> {
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/**
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* The internal cache for this set.
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*/
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@NonNull private final ExpiringMap<T, Long> cache;
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/**
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* The lifetime (in millis) of the elements in this set.
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*/
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private final long lifetime;
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public ExpiringSet(@NonNull ExpirationPolicy expirationPolicy, long duration, @NonNull TimeUnit timeUnit) {
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this(expirationPolicy, duration, timeUnit, ignored -> {});
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}
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public ExpiringSet(@NonNull ExpirationPolicy expirationPolicy, long duration, @NonNull TimeUnit timeUnit, @NonNull Consumer<T> onExpire) {
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//noinspection unchecked
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this.cache = ExpiringMap.builder()
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.expirationPolicy(expirationPolicy)
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.expiration(duration, timeUnit)
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.expirationListener((key, ignored) -> onExpire.accept((T) key))
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.build();
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this.lifetime = timeUnit.toMillis(duration); // Get the lifetime in millis
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}
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/**
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* Add an element to this set.
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*
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* @param element the element
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* @return whether the element was added
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*/
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public boolean add(@NonNull T element) {
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boolean contains = contains(element); // Does this set already contain the element?
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this.cache.put(element, System.currentTimeMillis() + this.lifetime);
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return !contains;
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}
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/**
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* Get the entry time of an element in this set.
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*
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* @param element the element
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* @return the entry time, -1 if not contained
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*/
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public long getEntryTime(@NonNull T element) {
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return contains(element) ? this.cache.get(element) - this.lifetime : -1L;
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}
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/**
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* Check if an element is
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* contained within this set.
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*
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* @param element the element
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* @return whether the element is contained
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*/
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public boolean contains(@NonNull T element) {
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Long timeout = this.cache.get(element); // Get the timeout for the element
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return timeout != null && (timeout > System.currentTimeMillis());
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}
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/**
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* Check if this set is empty.
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*
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* @return whether this set is empty
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*/
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public boolean isEmpty() {
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return this.cache.isEmpty();
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}
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/**
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* Get the size of this set.
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*
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* @return the size
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*/
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public int size() {
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return this.cache.size();
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}
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/**
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* Remove an element from this set.
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*
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* @param element the element
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* @return whether the element was removed
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*/
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public boolean remove(@NonNull T element) {
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return this.cache.remove(element) != null;
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}
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/**
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* Clear this set.
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*/
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public void clear() {
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this.cache.clear();
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}
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/**
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* Get the elements in this set.
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*
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* @return the elements
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*/
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@NonNull
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public Set<T> getElements() {
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return this.cache.keySet();
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}
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/**
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* Returns an iterator over elements of type {@code T}.
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*
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* @return an Iterator.
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*/
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@Override @NonNull
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public Iterator<T> iterator() {
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return this.cache.keySet().iterator();
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}
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}
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