Avoid a hard dependency on Sun's CachedRowSetImpl class

jhoeller · jhoeller · commit 9e337d27054f · 2012-11-25T22:20:25.000+01:00
Also using the JDBC 4.1 RowSetProvider API directly instead of going through reflection, since we're building on JDK 7 now.
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/SqlRowSetResultSetExtractor.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/SqlRowSetResultSetExtractor.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,20 +16,21 @@
 
 package org.springframework.jdbc.core;
 
-import java.lang.reflect.Method;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import javax.sql.rowset.CachedRowSet;
+import javax.sql.rowset.RowSetFactory;
+import javax.sql.rowset.RowSetProvider;
 
 import com.sun.rowset.CachedRowSetImpl;
 
+import org.springframework.core.JdkVersion;
 import org.springframework.jdbc.support.rowset.ResultSetWrappingSqlRowSet;
 import org.springframework.jdbc.support.rowset.SqlRowSet;
-import org.springframework.util.ReflectionUtils;
 
 /**
- * ResultSetExtractor implementation that returns a Spring SqlRowSet
- * representation for each given ResultSet.
+ * {@link ResultSetExtractor} implementation that returns a Spring {@link SqlRowSet}
+ * representation for each given {@link ResultSet}.
  *
  * <p>The default implementation uses a standard JDBC CachedRowSet underneath.
  * This means that JDBC RowSet support needs to be available at runtime:
@@ -45,20 +46,16 @@
  */
 public class SqlRowSetResultSetExtractor implements ResultSetExtractor<SqlRowSet> {
 
-	private static Object rowSetFactory = null;
-
-	private static Method createCachedRowSet = null;
+	private static final CachedRowSetFactory cachedRowSetFactory;
 
 	static {
-		ClassLoader cl = SqlRowSetResultSetExtractor.class.getClassLoader();
-		try {
-			Class rowSetProviderClass = cl.loadClass("javax.sql.rowset.RowSetProvider");
-			Method newFactory = rowSetProviderClass.getMethod("newFactory");
-			rowSetFactory = ReflectionUtils.invokeMethod(newFactory, null);
-			createCachedRowSet = rowSetFactory.getClass().getMethod("createCachedRowSet");
+		if (JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_17) {
+			// using JDBC 4.1 RowSetProvider
+			cachedRowSetFactory = new StandardCachedRowSetFactory();
 		}
-		catch (Exception ex) {
+		else {
 			// JDBC 4.1 API not available - fall back to Sun CachedRowSetImpl
+			cachedRowSetFactory = new SunCachedRowSetFactory();
 		}
 	}
 
@@ -88,19 +85,56 @@ protected SqlRowSet createSqlRowSet(ResultSet rs) throws SQLException {
 	/**
 	 * Create a new CachedRowSet instance, to be populated by
 	 * the <code>createSqlRowSet</code> implementation.
-	 * <p>The default implementation creates a new instance of
-	 * Sun's <code>com.sun.rowset.CachedRowSetImpl</code> class.
+	 * <p>The default implementation uses JDBC 4.1's RowSetProvider
+	 * when running on JDK 7 or higher, falling back to Sun's
+	 * <code>com.sun.rowset.CachedRowSetImpl</code> class on older JDKs.
 	 * @return a new CachedRowSet instance
 	 * @throws SQLException if thrown by JDBC methods
 	 * @see #createSqlRowSet
 	 * @see com.sun.rowset.CachedRowSetImpl
 	 */
 	protected CachedRowSet newCachedRowSet() throws SQLException {
-		if (createCachedRowSet != null) {
-			// RowSetProvider.newFactory().createCachedRowSet();
-			return (CachedRowSet) ReflectionUtils.invokeJdbcMethod(createCachedRowSet, rowSetFactory);
+		return cachedRowSetFactory.createCachedRowSet();
+	}
+
+
+	/**
+	 * Internal strategy interface for the creation of CachedRowSet instances.
+	 */
+	private interface CachedRowSetFactory {
+
+		CachedRowSet createCachedRowSet() throws SQLException;
+	}
+
+
+	/**
+	 * Inner class to avoid a hard dependency on JDBC 4.1 RowSetProvider class.
+	 */
+	private static class StandardCachedRowSetFactory implements CachedRowSetFactory {
+
+		private final RowSetFactory rowSetFactory;
+
+		public StandardCachedRowSetFactory() {
+			try {
+				this.rowSetFactory = RowSetProvider.newFactory();
+			}
+			catch (SQLException ex) {
+				throw new IllegalStateException("Cannot create RowSetFactory through RowSetProvider", ex);
+			}
 		}
-		else {
+
+		public CachedRowSet createCachedRowSet() throws SQLException {
+			return this.rowSetFactory.createCachedRowSet();
+		}
+	}
+
+
+	/**
+	 * Inner class to avoid a hard dependency on Sun's CachedRowSetImpl class.
+	 */
+	private static class SunCachedRowSetFactory implements CachedRowSetFactory {
+
+		public CachedRowSet createCachedRowSet() throws SQLException {
 			return new CachedRowSetImpl();
 		}
 	}
