source: Ballon/web/WEB-INF/lib/mysql-connector-java-5.1.21/src/com/mysql/jdbc/PerConnectionLRUFactory.java @ 766

/*
  Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

  The MySQL Connector/J is licensed under the terms of the GPLv2
  <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most MySQL Connectors.
  There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
  this software, see the FLOSS License Exception
  <http://www.mysql.com/about/legal/licensing/foss-exception.html>.

  This program 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; version 2
  of the License.

  This program 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 this
  program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
  Floor, Boston, MA 02110-1301  USA
 
 */

package com.mysql.jdbc;

import java.sql.SQLException;
import java.util.Properties;

import com.mysql.jdbc.PreparedStatement.ParseInfo;
import com.mysql.jdbc.util.LRUCache;

public class PerConnectionLRUFactory implements CacheAdapterFactory<String, ParseInfo> {

        public CacheAdapter<String, ParseInfo> getInstance(Connection forConnection,
                        String url, int cacheMaxSize, int maxKeySize,
                        Properties connectionProperties) throws SQLException {

                return new PerConnectionLRU(forConnection, cacheMaxSize, maxKeySize);
        }

        class PerConnectionLRU implements CacheAdapter<String, ParseInfo> {
                private final int cacheSqlLimit;
                private final LRUCache cache;
                private final Connection conn;
                
                protected PerConnectionLRU(Connection forConnection, int cacheMaxSize,
                                int maxKeySize) {
                        final int cacheSize = cacheMaxSize;
                        cacheSqlLimit = maxKeySize;
                        cache = new LRUCache(cacheSize);
                        conn = forConnection;
                }
                
                public ParseInfo get(String key) {
                        if (key == null || key.length() > cacheSqlLimit) {
                                return null;
                        }

                        synchronized (conn) {
                                return (ParseInfo) cache.get(key);
                        }
                }

                public void put(String key, ParseInfo value) {
                        if (key == null || key.length() > cacheSqlLimit) {
                                return;
                        }

                        synchronized (conn) {
                                cache.put(key, value);
                        }
                }
        }
}