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java LRUCache
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package org.rx.cache; import org.rx.common.*; import org.rx.beans.DateTime; import java.util.Collections; import java.util.LinkedHashMap; import java.util.Map; import java.util.concurrent.Future; import java.util.function.Consumer; import java.util.function.Function; import static org.rx.common.Contract.as; import static org.rx.common.Contract.require; import static org.rx.util.AsyncTask.TaskFactory; public final class LRUCache<TK, TV> extends Disposable { private class CacheItem { public TV value; private int expireSeconds; private DateTime createTime; private Consumer<TV> expireCallback; public CacheItem(TV value, int expireSeconds, Consumer<TV> expireCallback) { this.value = value; this.expireSeconds = expireSeconds; this.expireCallback = expireCallback; refresh(); } public void refresh() { if (expireSeconds > -1) { createTime = DateTime.utcNow(); } } public void callback() { if (expireCallback != null) { expireCallback.accept(value); } } } private static final Lazy<LRUCache<String, Object>> instance = new Lazy<>(() -> new LRUCache<>(1000, 120)); public static LRUCache<String, Object> getInstance() { return instance.getValue(); } public static Object getOrStore(String key, Function<String, Object> supplier) { require(key, supplier); return getInstance().getOrAdd(App.cacheKey(key), p -> supplier.apply(key)); } private final Map<TK, CacheItem> cache; private int maxCapacity; private int expireSeconds; private Consumer<TV> expireCallback; private Future future; public LRUCache(int maxSize, int expireSecondsAfterAccess) { this(maxSize, expireSecondsAfterAccess, 8 * 1000, null); } public LRUCache(int maxSize, int expireSecondsAfterAccess, long checkPeriod, Consumer<TV> removeCallback) { cache = Collections.synchronizedMap(new LinkedHashMap<TK, CacheItem>(maxSize + 1, .75F, true) { @Override protected boolean removeEldestEntry(Map.Entry<TK, CacheItem> eldest) { boolean remove = size() > maxCapacity; if (remove) { eldest.getValue().callback(); } return remove; } }); maxCapacity = maxSize; expireSeconds = expireSecondsAfterAccess; expireCallback = removeCallback; future = TaskFactory.schedule(() -> { for (Map.Entry<TK, CacheItem> entry : NQuery.of(cache.entrySet()).where(p -> p.getValue().expireSeconds > -1 && DateTime.utcNow().addSeconds(-p.getValue().expireSeconds).after(p.getValue().createTime))) { entry.getValue().callback(); cache.remove(entry.getKey()); } }, checkPeriod); } @Override protected void freeObjects() { if (future != null) { future.cancel(true); } cache.clear(); } public void add(TK key, TV val) { add(key, val, expireSeconds, expireCallback); } public void add(TK key, TV val, int expireSecondsAfterAccess, Consumer<TV> removeCallback) { require(key); cache.put(key, new CacheItem(val, expireSecondsAfterAccess, removeCallback)); } public void remove(TK key) { remove(key, true); } public void remove(TK key, boolean destroy) { require(key); CacheItem remove = cache.remove(key); if (remove == null) { return; } AutoCloseable ac; if (destroy && (ac = as(remove.value, AutoCloseable.class)) != null) { try { ac.close(); } catch (Exception ex) { Logger.error(ex, "Auto close error"); } } } public TV get(TK key) { require(key); CacheItem item = cache.get(key); if (item == null) { return null; } item.refresh(); return item.value; } public TV getOrAdd(TK key, Function<TK, TV> supplier) { require(key, supplier); CacheItem item = cache.get(key); if (item == null) { cache.put(key, item = new CacheItem(supplier.apply(key), expireSeconds, expireCallback)); } else { item.refresh(); } return item.value; } }
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