Mercurial > hg > release > thermostat-1.6
view web/client/src/main/java/com/redhat/thermostat/web/client/internal/WebPreparedStatementCache.java @ 2049:a92d602216ad
Update copyright license headers for 2017
PR3290
Reviewed-by: jerboaa
Review-thread: http://icedtea.classpath.org/pipermail/thermostat/2017-January/021974.html
author | Andrew Azores <aazores@redhat.com> |
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date | Tue, 17 Jan 2017 12:19:56 -0500 |
parents | 31f274ab27a5 |
children |
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/* * Copyright 2012-2017 Red Hat, Inc. * * This file is part of Thermostat. * * Thermostat is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published * by the Free Software Foundation; either version 2, or (at your * option) any later version. * * Thermostat is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Thermostat; see the file COPYING. If not see * <http://www.gnu.org/licenses/>. * * Linking this code with other modules is making a combined work * based on this code. Thus, the terms and conditions of the GNU * General Public License cover the whole combination. * * As a special exception, the copyright holders of this code give * you permission to link this code with independent modules to * produce an executable, regardless of the license terms of these * independent modules, and to copy and distribute the resulting * executable under terms of your choice, provided that you also * meet, for each linked independent module, the terms and conditions * of the license of that module. An independent module is a module * which is not derived from or based on this code. If you modify * this code, you may extend this exception to your version of the * library, but you are not obligated to do so. If you do not wish * to do so, delete this exception statement from your version. */ package com.redhat.thermostat.web.client.internal; import java.util.Map; import java.util.WeakHashMap; import com.redhat.thermostat.storage.core.StatementDescriptor; import com.redhat.thermostat.storage.model.Pojo; import com.redhat.thermostat.web.common.SharedStateId; import com.redhat.thermostat.web.common.WebPreparedStatement; /** * A simple implementation of a cache for {@link WebPreparedStatement} * in order to avoid unnecessary network round-trips if a statement * has already been prepared and it's not out-of-sync with the server. */ class WebPreparedStatementCache { private final Map<StatementDescriptor<?>, WebPreparedStatementHolder> stmtCache; private final Map<SharedStateId, StatementDescriptor<?>> reverseLookup; WebPreparedStatementCache() { stmtCache = new WeakHashMap<>(); reverseLookup = new WeakHashMap<>(); } synchronized <T extends Pojo> void put(StatementDescriptor<T> desc, WebPreparedStatementHolder holder) { SharedStateId id = holder.getStatementId(); stmtCache.put(desc, holder); reverseLookup.put(id, desc); } synchronized <T extends Pojo> WebPreparedStatementHolder get(StatementDescriptor<T> desc) { return stmtCache.get(desc); } @SuppressWarnings("unchecked") synchronized <T extends Pojo> StatementDescriptor<T> get(SharedStateId id) { return (StatementDescriptor<T>)reverseLookup.get(id); } synchronized void remove(SharedStateId id) { StatementDescriptor<?> desc = reverseLookup.get(id); if (desc != null) { stmtCache.remove(desc); } reverseLookup.remove(id); } /** * Creates a snapshot of the current state of this cache. * * @return A copied snapshot of this cache. */ synchronized WebPreparedStatementCache createSnapshot() { WebPreparedStatementCache copy = new WebPreparedStatementCache(); for (StatementDescriptor<?> desc: stmtCache.keySet()) { copy.put(desc, stmtCache.get(desc)); } return copy; } }