78 lines
2.2 KiB
Java
78 lines
2.2 KiB
Java
package com.imaginarycode.minecraft.redisbungee.util;
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import lombok.Data;
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import java.util.Iterator;
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import java.util.Map;
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import java.util.concurrent.Callable;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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import java.util.concurrent.ExecutionException;
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// I would use the Guava cache, but can't because I need a few more properties.
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public class InternalCache<K, V> {
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private final ConcurrentMap<K, Holder> map = new ConcurrentHashMap<>(128, 0.75f, 4);
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private final long entryWriteExpiry;
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public InternalCache() {
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this.entryWriteExpiry = 0;
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}
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public InternalCache(long entryWriteExpiry) {
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this.entryWriteExpiry = entryWriteExpiry;
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}
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public V get(K key, Callable<V> loader) throws ExecutionException {
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Holder value = map.get(key);
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if (value == null || (entryWriteExpiry > 0 && System.currentTimeMillis() > value.expiry)) {
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V freshValue;
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try {
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freshValue = loader.call();
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} catch (Exception e) {
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throw new ExecutionException(e);
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}
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if (freshValue == null)
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return null;
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map.putIfAbsent(key, value = new Holder(freshValue, System.currentTimeMillis() + entryWriteExpiry));
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}
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return value.value;
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}
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public V put(K key, V value) {
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Holder holder = map.put(key, new Holder(value, System.currentTimeMillis() + entryWriteExpiry));
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if (holder == null)
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return null;
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return holder.value;
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}
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public void invalidate(K key) {
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map.remove(key);
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}
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// Run periodically to clean up the cache mappings.
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public void cleanup() {
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if (entryWriteExpiry <= 0)
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return;
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long fixedReference = System.currentTimeMillis();
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for (Iterator<Map.Entry<K, Holder>> it = map.entrySet().iterator(); it.hasNext(); ) {
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Map.Entry<K, Holder> entry = it.next();
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if (entry.getValue().expiry > fixedReference)
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it.remove();
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}
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}
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@Data
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private class Holder {
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private final V value;
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private final long expiry;
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}
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}
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