~~~ package org.apache.ibatis.cache.decorators; import java.util.concurrent.TimeUnit; import org.apache.ibatis.cache.Cache; /** * @author Clinton Begin */ public class ScheduledCache implements Cache { private final Cache delegate; protected long clearInterval; protected long lastClear; public ScheduledCache(Cache delegate) { this.delegate = delegate; //將一小時轉換成毫秒數 this.clearInterval = TimeUnit.HOURS.toMillis(1); //系統當前毫秒數 this.lastClear = System.currentTimeMillis(); } public void setClearInterval(long clearInterval) { this.clearInterval = clearInterval; } @Override public String getId() { return delegate.getId(); } @Override public int getSize() { clearWhenStale(); return delegate.getSize(); } @Override public void putObject(Object key, Object object) { clearWhenStale(); delegate.putObject(key, object); } @Override public Object getObject(Object key) { return clearWhenStale() ? null : delegate.getObject(key); } @Override public Object removeObject(Object key) { clearWhenStale(); return delegate.removeObject(key); } @Override public void clear() { lastClear = System.currentTimeMillis(); delegate.clear(); } @Override public int hashCode() { return delegate.hashCode(); } @Override public boolean equals(Object obj) { return delegate.equals(obj); } //超過一小時就執行清除 private boolean clearWhenStale() { if (System.currentTimeMillis() - lastClear > clearInterval) { clear(); return true; } return false; } } ~~~