RowBounds with out-of-range offset causes SQLException on DB2

Reported on the mailing list.
https://groups.google.com/d/msg/mybatis-user/21UM4I7gm48/CRJShn2iBgAJ

Author: harawata

src/main/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandler.java

@@ -347,11 +347,12 @@ protected void checkResultHandler() {
   private void handleRowValuesForSimpleResultMap(ResultSetWrapper rsw, ResultMap resultMap, ResultHandler<?> resultHandler, RowBounds rowBounds, ResultMapping parentMapping)
       throws SQLException {
     DefaultResultContext<Object> resultContext = new DefaultResultContext<>();
-    skipRows(rsw.getResultSet(), rowBounds);
-    while (shouldProcessMoreRows(resultContext, rowBounds) && rsw.getResultSet().next()) {
-      ResultMap discriminatedResultMap = resolveDiscriminatedResultMap(rsw.getResultSet(), resultMap, null);
+    ResultSet resultSet = rsw.getResultSet();
+    skipRows(resultSet, rowBounds);
+    while (shouldProcessMoreRows(resultContext, rowBounds) && !resultSet.isClosed() && resultSet.next()) {
+      ResultMap discriminatedResultMap = resolveDiscriminatedResultMap(resultSet, resultMap, null);
       Object rowValue = getRowValue(rsw, discriminatedResultMap, null);
-      storeObject(resultHandler, resultContext, rowValue, parentMapping, rsw.getResultSet());
+      storeObject(resultHandler, resultContext, rowValue, parentMapping, resultSet);
     }
   }
 
@@ -380,7 +381,9 @@ private void skipRows(ResultSet rs, RowBounds rowBounds) throws SQLException {
       }
     } else {
       for (int i = 0; i < rowBounds.getOffset(); i++) {
-        rs.next();
+        if (!rs.next()) {
+          break;
+        }
       }
     }
   }
@@ -846,28 +849,29 @@ private String prependPrefix(String columnName, String prefix) {
 
   private void handleRowValuesForNestedResultMap(ResultSetWrapper rsw, ResultMap resultMap, ResultHandler<?> resultHandler, RowBounds rowBounds, ResultMapping parentMapping) throws SQLException {
     final DefaultResultContext<Object> resultContext = new DefaultResultContext<>();
-    skipRows(rsw.getResultSet(), rowBounds);
+    ResultSet resultSet = rsw.getResultSet();
+    skipRows(resultSet, rowBounds);
     Object rowValue = previousRowValue;
-    while (shouldProcessMoreRows(resultContext, rowBounds) && rsw.getResultSet().next()) {
-      final ResultMap discriminatedResultMap = resolveDiscriminatedResultMap(rsw.getResultSet(), resultMap, null);
+    while (shouldProcessMoreRows(resultContext, rowBounds) && !resultSet.isClosed() && resultSet.next()) {
+      final ResultMap discriminatedResultMap = resolveDiscriminatedResultMap(resultSet, resultMap, null);
       final CacheKey rowKey = createRowKey(discriminatedResultMap, rsw, null);
       Object partialObject = nestedResultObjects.get(rowKey);
       // issue #577 && #542
       if (mappedStatement.isResultOrdered()) {
         if (partialObject == null && rowValue != null) {
           nestedResultObjects.clear();
-          storeObject(resultHandler, resultContext, rowValue, parentMapping, rsw.getResultSet());
+          storeObject(resultHandler, resultContext, rowValue, parentMapping, resultSet);
         }
         rowValue = getRowValue(rsw, discriminatedResultMap, rowKey, null, partialObject);
       } else {
         rowValue = getRowValue(rsw, discriminatedResultMap, rowKey, null, partialObject);
         if (partialObject == null) {
-          storeObject(resultHandler, resultContext, rowValue, parentMapping, rsw.getResultSet());
+          storeObject(resultHandler, resultContext, rowValue, parentMapping, resultSet);
         }
       }
     }
     if (rowValue != null && mappedStatement.isResultOrdered() && shouldProcessMoreRows(resultContext, rowBounds)) {
-      storeObject(resultHandler, resultContext, rowValue, parentMapping, rsw.getResultSet());
+      storeObject(resultHandler, resultContext, rowValue, parentMapping, resultSet);
       previousRowValue = null;
     } else if (rowValue != null) {
       previousRowValue = rowValue;

src/test/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandlerTest2.java

@@ -0,0 +1,217 @@
+/**
+ *    Copyright 2009-2018 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.
+ *    You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.executor.resultset;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.ibatis.builder.StaticSqlSource;
+import org.apache.ibatis.executor.Executor;
+import org.apache.ibatis.executor.parameter.ParameterHandler;
+import org.apache.ibatis.mapping.BoundSql;
+import org.apache.ibatis.mapping.MappedStatement;
+import org.apache.ibatis.mapping.ResultMap;
+import org.apache.ibatis.mapping.ResultMapping;
+import org.apache.ibatis.mapping.SqlCommandType;
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.session.ResultHandler;
+import org.apache.ibatis.session.RowBounds;
+import org.apache.ibatis.type.TypeHandlerRegistry;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Spy;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class DefaultResultSetHandlerTest2 {
+
+  @Spy
+  private ImpatientResultSet rs;
+  @Mock
+  private Statement stmt;
+  @Mock
+  protected ResultSetMetaData rsmd;
+  @Mock
+  private Connection conn;
+  @Mock
+  private DatabaseMetaData dbmd;
+
+  @SuppressWarnings("serial")
+  @Test
+  public void shouldNotCallNextOnClosedResultSet_SimpleResult() throws Exception {
+    final Configuration config = new Configuration();
+    final TypeHandlerRegistry registry = config.getTypeHandlerRegistry();
+    final MappedStatement ms = new MappedStatement.Builder(config, "testSelect",
+      new StaticSqlSource(config, "some select statement"), SqlCommandType.SELECT).resultMaps(
+        new ArrayList<ResultMap>() {
+          {
+            add(new ResultMap.Builder(config, "testMap", HashMap.class, new ArrayList<ResultMapping>() {
+              {
+                add(new ResultMapping.Builder(config, "id", "id", registry.getTypeHandler(Integer.class)).build());
+              }
+            }).build());
+          }
+        }).build();
+
+    final Executor executor = null;
+    final ParameterHandler parameterHandler = null;
+    final ResultHandler<?> resultHandler = null;
+    final BoundSql boundSql = null;
+    final RowBounds rowBounds = new RowBounds(5, 1);
+    final DefaultResultSetHandler resultSetHandler = new DefaultResultSetHandler(executor, ms, parameterHandler,
+      resultHandler, boundSql, rowBounds);
+
+    when(stmt.getResultSet()).thenReturn(rs);
+    when(rsmd.getColumnCount()).thenReturn(1);
+    when(rsmd.getColumnLabel(1)).thenReturn("id");
+    when(rsmd.getColumnType(1)).thenReturn(Types.INTEGER);
+    when(rsmd.getColumnClassName(1)).thenReturn(Integer.class.getCanonicalName());
+    when(stmt.getConnection()).thenReturn(conn);
+    when(conn.getMetaData()).thenReturn(dbmd);
+    when(dbmd.supportsMultipleResultSets()).thenReturn(false); // for simplicity.
+
+    final List<Object> results = resultSetHandler.handleResultSets(stmt);
+    assertEquals(0, results.size());
+  }
+
+  @SuppressWarnings("serial")
+  @Test
+  public void shouldNotCallNextOnClosedResultSet_NestedResult() throws Exception {
+    final Configuration config = new Configuration();
+    final TypeHandlerRegistry registry = config.getTypeHandlerRegistry();
+    final ResultMap nestedResultMap = new ResultMap.Builder(config, "roleMap", HashMap.class,
+      new ArrayList<ResultMapping>() {
+        {
+          add(new ResultMapping.Builder(config, "role", "role", registry.getTypeHandler(String.class))
+            .build());
+        }
+      }).build();
+    config.addResultMap(nestedResultMap);
+    final MappedStatement ms = new MappedStatement.Builder(config, "selectPerson",
+      new StaticSqlSource(config, "select person..."),
+      SqlCommandType.SELECT).resultMaps(
+        new ArrayList<ResultMap>() {
+          {
+            add(new ResultMap.Builder(config, "personMap", HashMap.class, new ArrayList<ResultMapping>() {
+              {
+                add(new ResultMapping.Builder(config, "id", "id", registry.getTypeHandler(Integer.class))
+                  .build());
+                add(new ResultMapping.Builder(config, "roles").nestedResultMapId("roleMap").build());
+              }
+            }).build());
+          }
+        })
+        .resultOrdered(true)
+        .build();
+
+    final Executor executor = null;
+    final ParameterHandler parameterHandler = null;
+    final ResultHandler<?> resultHandler = null;
+    final BoundSql boundSql = null;
+    final RowBounds rowBounds = new RowBounds(5, 1);
+    final DefaultResultSetHandler resultSetHandler = new DefaultResultSetHandler(executor, ms, parameterHandler,
+      resultHandler, boundSql, rowBounds);
+
+    when(stmt.getResultSet()).thenReturn(rs);
+    when(rsmd.getColumnCount()).thenReturn(2);
+    when(rsmd.getColumnLabel(1)).thenReturn("id");
+    when(rsmd.getColumnType(1)).thenReturn(Types.INTEGER);
+    when(rsmd.getColumnClassName(1)).thenReturn(Integer.class.getCanonicalName());
+    when(rsmd.getColumnLabel(2)).thenReturn("role");
+    when(rsmd.getColumnType(2)).thenReturn(Types.VARCHAR);
+    when(rsmd.getColumnClassName(2)).thenReturn(String.class.getCanonicalName());
+    when(stmt.getConnection()).thenReturn(conn);
+    when(conn.getMetaData()).thenReturn(dbmd);
+    when(dbmd.supportsMultipleResultSets()).thenReturn(false); // for simplicity.
+
+    final List<Object> results = resultSetHandler.handleResultSets(stmt);
+    assertEquals(0, results.size());
+  }
+
+  /*
+   * Simulate a driver that closes ResultSet automatically when next() returns false (e.g. DB2).
+   */
+  protected abstract class ImpatientResultSet implements ResultSet {
+    private int rowIndex = -1;
+    private List<Map<String, Object>> rows = new ArrayList<>();
+
+    protected ImpatientResultSet() {
+      Map<String, Object> row = new HashMap<>();
+      row.put("id", Integer.valueOf(1));
+      row.put("role", "CEO");
+      rows.add(row);
+    }
+
+    @Override
+    public boolean next() throws SQLException {
+      throwIfClosed();
+      return ++rowIndex < rows.size();
+    }
+
+    @Override
+    public boolean isClosed() throws SQLException {
+      return rowIndex >= rows.size();
+    }
+
+    @Override
+    public String getString(String columnLabel) throws SQLException {
+      throwIfClosed();
+      return (String) rows.get(rowIndex).get(columnLabel);
+    }
+
+    @Override
+    public int getInt(String columnLabel) throws SQLException {
+      throwIfClosed();
+      return (Integer) rows.get(rowIndex).get(columnLabel);
+    }
+
+    @Override
+    public boolean wasNull() throws SQLException {
+      throwIfClosed();
+      return false;
+    }
+
+    @Override
+    public ResultSetMetaData getMetaData() throws SQLException {
+      return rsmd;
+    }
+
+    @Override
+    public int getType() throws SQLException {
+      throwIfClosed();
+      return ResultSet.TYPE_FORWARD_ONLY;
+    }
+
+    private void throwIfClosed() throws SQLException {
+      if (rowIndex >= rows.size()) {
+        throw new SQLException("Invalid operation: result set is closed.");
+      }
+    }
+  }
+}