[APIS-877] Improve JDBC driver to use statement cache

src/jdbc/cubrid/jdbc/driver/CUBRIDConnection.java

@@ -35,6 +35,7 @@
 import cubrid.jdbc.jci.UConnection;
 import cubrid.jdbc.jci.UError;
 import cubrid.jdbc.jci.UErrorCode;
+import cubrid.jdbc.jci.UPreparedStatementCache;
 import cubrid.jdbc.jci.UStatement;
 import java.sql.Array;
 import java.sql.Blob;
@@ -88,6 +89,7 @@ public class CUBRIDConnection implements Connection {
     protected CUBRIDShardMetaData shard_mdata;
     protected ArrayList<CUBRIDOutResultSet> outRs;
     private boolean isAutoGeneratedKeys = false;
+    protected UPreparedStatementCache<String, PreparedStatement> prepStmtCache;
 
     /*
      * 3.0 ArrayList savepoints; int sv_count, sv_id; String sv_name; private
@@ -109,6 +111,9 @@ public CUBRIDConnection(UConnection u, String r, String s) {
         statements = new ArrayList<Statement>();
         outRs = new ArrayList<CUBRIDOutResultSet>();
         shard_mdata = null;
+        prepStmtCache =
+                new UPreparedStatementCache<String, PreparedStatement>(
+                        u_con.getPrepStmtCacheSize());
 
         /*
          * 3.0 savepoints = new ArrayList(); sv_count = 0; sv_name = "";
@@ -811,6 +816,8 @@ protected PreparedStatement prepare(
             int resultHoldability,
             int autoGeneratedKeys)
             throws SQLException {
+        PreparedStatement pstmtCache = null;
+
         checkIsOpen();
 
         byte prepareFlag = (byte) 0;
@@ -824,6 +831,13 @@ protected PreparedStatement prepare(
             prepareFlag = UConnection.PREPARE_HOLDABLE;
         }
 
+        if (u_con.isPrepStmtCache(sql)) {
+            pstmtCache = prepStmtCache.get(sql);
+            if (pstmtCache != null) {
+                return pstmtCache;
+            }
+        }
+
         UStatement us = prepare(sql, prepareFlag);
         PreparedStatement pstmt =
                 new CUBRIDPreparedStatement(
@@ -835,6 +849,9 @@ protected PreparedStatement prepare(
                         autoGeneratedKeys);
         addStatement(pstmt);
 
+        if (u_con.isPrepStmtCache(sql)) {
+            prepStmtCache.put(sql, pstmt);
+        }
         return pstmt;
     }
 

src/jdbc/cubrid/jdbc/driver/CUBRIDPreparedStatement.java

@@ -721,17 +721,24 @@ public void close() throws SQLException {
         try {
             synchronized (con) {
                 synchronized (this) {
+                    String sql = "";
+
                     setShardId(UShardInfo.SHARD_ID_INVALID);
                     if (is_closed) return;
 
                     complete();
                     is_closed = true;
 
                     if (u_stmt != null) {
+                        sql = u_stmt.getQuery();
                         u_stmt.close();
                         u_stmt = null;
                     }
 
+                    if (u_con.isPrepStmtCache(sql)) {
+                        con.prepStmtCache.remove(sql);
+                    }
+
                     con.removeStatement(this);
                     con = null;
                     u_con = null;

src/jdbc/cubrid/jdbc/driver/ConnectionProperties.java

@@ -395,6 +395,15 @@ private int getDefaultConnectTimeout() {
 
     BooleanConnectionProperty holdCursor = new BooleanConnectionProperty("hold_cursor", true);
 
+    BooleanConnectionProperty usePreparedStmtCache =
+            new BooleanConnectionProperty("usePreparedStmtCache", false);
+
+    IntegerConnectionProperty preparedStmtCacheSize =
+            new IntegerConnectionProperty("preparedStmtCacheSize", 25, 1, Integer.MAX_VALUE);
+
+    IntegerConnectionProperty preparedStmtCacheSqlLimit =
+            new IntegerConnectionProperty("preparedStmtCacheSqlLimit", 256, 1, Integer.MAX_VALUE);
+
     public boolean getLogOnException() {
         return logOnException.getValueAsBoolean();
     }
@@ -470,4 +479,16 @@ public int getHoldCursor() {
         }
         return holdability;
     }
+
+    public boolean getPrepStmtCache() {
+        return usePreparedStmtCache.getValueAsBoolean();
+    }
+
+    public int getPrepStmtCacheSize() {
+        return preparedStmtCacheSize.getValueAsInteger();
+    }
+
+    public int getPrepStmtCacheSqlLimit() {
+        return preparedStmtCacheSqlLimit.getValueAsInteger();
+    }
 }

src/jdbc/cubrid/jdbc/jci/UConnection.java

@@ -1490,6 +1490,27 @@ public int getClientCacheSize() {
         return connectionProperties.getClientCacheSize() * 1024 * 1024;
     }
 
+    public boolean getPrepStmtCache() {
+        return connectionProperties.getPrepStmtCache();
+    }
+
+    public int getPrepStmtCacheSize() {
+        return connectionProperties.getPrepStmtCacheSize();
+    }
+
+    public int getPrepStmtCacheSqlLimit() {
+        return connectionProperties.getPrepStmtCacheSqlLimit();
+    }
+
+    public boolean isPrepStmtCache(String sql) {
+        boolean isCacheable = false;
+        if (connectionProperties.getPrepStmtCache()
+                && sql.length() <= connectionProperties.getPrepStmtCacheSqlLimit()) {
+            isCacheable = true;
+        }
+        return isCacheable;
+    }
+
     public void setCasIp(String casIp) {
         this.casIp = casIp;
     }

src/jdbc/cubrid/jdbc/jci/UPreparedStatementCache.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2016 CUBRID Corporation.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the <ORGANIZATION> nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software without
+ *   specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ */
+
+package cubrid.jdbc.jci;
+
+import java.util.LinkedHashMap;
+import java.util.Map.Entry;
+
+public class UPreparedStatementCache<K, V> extends LinkedHashMap<K, V> {
+    private static final long serialVersionUID = 1L;
+    protected int maxCacheSize;
+
+    public UPreparedStatementCache(int maxCacheSize) {
+        super(maxCacheSize, 0.75F, true);
+        this.maxCacheSize = maxCacheSize;
+    }
+
+    @Override
+    public V get(Object key) {
+        synchronized (this) {
+            return super.get(key);
+        }
+    }
+
+    @Override
+    public V put(K key, V value) {
+        synchronized (this) {
+            return super.put(key, value);
+        }
+    }
+
+    @Override
+    public V remove(Object key) {
+        synchronized (this) {
+            return super.remove(key);
+        }
+    }
+
+    @Override
+    protected boolean removeEldestEntry(Entry<K, V> eldest) {
+        return (size() > this.maxCacheSize);
+    }
+}