Backport #762 to Jaybird 5.0.5

#762 Remove restriction to only allow calls to getResultSet if the result set was not returned yet

src/docs/asciidoc/release_notes.adoc

@@ -53,6 +53,12 @@ This feature was backported from Jaybird 6.
 +
 This improvement was backported from Jaybird 6.
 * Fixed: `ResultSet.isBeforeFirst()` and `ResultSet.isAfterLast()` should always report `false` for an empty result set (https://github.com/FirebirdSQL/jaybird/issues/807[#807])
+* Improvement: `Statement.getResultSet` no longer throws a `SQLException` with message "`Only one result set at a time/statement`" if the current result set has already been returned by `executeQuery` or a previous call to `getResultSet` (https://github.com/FirebirdSQL/jaybird/issues/762[#762])
++
+Repeated calls to `getResultSet` will now return the current result set.
+As part of this change implementations of `FirebirdStatement.getCurrentResultSet` now simply returns `getResultSet`, and the `getCurrentResultSet` method has been deprecated for removal in Jaybird 7.
++
+This improvement was backported from Jaybird 6.
 * ...
 
 [#jaybird-5-0-4-changelog]

src/main/org/firebirdsql/jdbc/FBCallableStatement.java

@@ -47,7 +47,6 @@ public class FBCallableStatement extends FBPreparedStatement implements Callable
     static final String NATIVE_CALL_COMMAND = "EXECUTE PROCEDURE ";
     static final String NATIVE_SELECT_COMMAND = "SELECT * FROM ";
 
-    private ResultSet currentRs;
     private ResultSet singletonRs;
 
     protected boolean selectableProcedure;
@@ -171,10 +170,7 @@ public boolean isSelectableProcedure() {
      * @throws SQLException if something went wrong.
      */
     protected void setRequiredTypes() throws SQLException {
-        if (singletonRs != null) {
-            setRequiredTypesInternal((FBResultSet) singletonRs);
-        }
-        setRequiredTypesInternal((FBResultSet) getCurrentResultSet());
+        setRequiredTypesInternal((FBResultSet) (singletonRs != null ? singletonRs : getResultSet()));
     }
 
     private void setRequiredTypesInternal(FBResultSet resultSet) throws SQLException {
@@ -246,16 +242,16 @@ public boolean execute() throws SQLException {
     public ResultSet executeQuery() throws SQLException {
         procedureCall.checkParameters();
         try (LockCloseable ignored = withLock()) {
+            checkValidity();
             notifyStatementStarted();
             prepareFixedStatement(procedureCall.getSQL(isSelectableProcedure()));
 
             if (!internalExecute(!isSelectableProcedure()))
                 throw new FBSQLException("No resultset for sql", SQLStateConstants.SQL_STATE_NO_RESULT_SET);
 
-            getResultSet();
-            setRequiredTypes();
-
-            return getCurrentResultSet();
+            ResultSet rs = getResultSet();
+            setRequiredTypesInternal((FBResultSet) rs);
+            return rs;
         }
     }
 
@@ -293,7 +289,6 @@ public int executeUpdate() throws SQLException {
     // Execute statement internally. This method sets cached parameters. Rest of the processing is done by superclass.
     @Override
     protected boolean internalExecute(boolean sendOutParams) throws SQLException {
-        currentRs = null;
         singletonRs = null;
         int counter = 0;
         for (FBProcedureParam param : procedureCall.getInputParams()) {
@@ -1107,14 +1102,6 @@ protected void assertHasData(ResultSet rs) throws SQLException {
         }
     }
 
-    // this method doesn't give an exception if it is called twice.
-    @Override
-    public ResultSet getCurrentResultSet() throws SQLException {
-        if (currentRs == null)
-            currentRs = super.getResultSet();
-        return currentRs;
-    }
-
     /**
      * Returns the result set for the singleton row of the callable statement and asserts it has data. If this is a
      * selectable procedure, or there is no singleton row, it will return the normal result set.
@@ -1127,28 +1114,11 @@ public ResultSet getCurrentResultSet() throws SQLException {
      * @throws SQLException For database access errors
      */
     protected ResultSet getAndAssertSingletonResultSet() throws SQLException {
-        final ResultSet rs;
-        if (!isSelectableProcedure() && singletonRs != null) {
-            rs = singletonRs;
-        } else {
-            rs = getCurrentResultSet();
-        }
+        final ResultSet rs = !isSelectableProcedure() && singletonRs != null ? singletonRs : getResultSet();
         assertHasData(rs);
         return rs;
     }
 
-    /**
-     * {@inheritDoc}
-     * <p>
-     * Calling this method twice with autocommit on and used will probably
-     * throw an inappropriate or uninformative exception.
-     * </p>
-     */
-    @Override
-    public ResultSet getResultSet() throws SQLException {
-        return getCurrentResultSet();
-    }
-
     @Override
     public void setBigDecimal(int parameterIndex, BigDecimal x) throws SQLException {
         procedureCall.getInputParam(parameterIndex).setValue(x);

src/main/org/firebirdsql/jdbc/FBStatement.java

@@ -530,26 +530,26 @@ public ResultSet getResultSet() throws SQLException {
     public ResultSet getResultSet(boolean metaDataQuery) throws  SQLException {
         if (fbStatement == null) {
             throw new FBSQLException("No statement was executed.");
+        } else if (currentRs != null) {
+            return currentRs;
         }
 
         if (cursorName != null) {
             fbStatement.setCursorName(cursorName);
         }
 
-        if (currentRs != null) {
-            throw new FBSQLException("Only one result set at a time/statement.");
-        }
-
         // A generated keys query does not produce a normal result set (but EXECUTE PROCEDURE or INSERT ... RETURNING without Statement.RETURN_GENERATED_KEYS do)
         // TODO Behavior might not be correct for callable statement implementation
         if (!isGeneratedKeyQuery() && currentStatementResult.isResultSet()) {
             if (!isSingletonResult) {
-                currentRs = new FBResultSet(connection, this, fbStatement, resultSetListener, metaDataQuery, rsType,
-                        rsConcurrency, rsHoldability, false);
+                if (cursorName != null) {
+                    fbStatement.setCursorName(cursorName);
+                }
+                return currentRs = new FBResultSet(connection, this, fbStatement, resultSetListener, metaDataQuery,
+                        rsType, rsConcurrency, rsHoldability, false);
             } else if (!specialResult.isEmpty()) {
-                currentRs = createSpecialResultSet(resultSetListener);
+                return currentRs = createSpecialResultSet(resultSetListener);
             }
-            return currentRs;
         }
         return null;
     }
@@ -826,9 +826,16 @@ void closeResultSet(boolean notifyListener, CompletionReason completionReason) t
         }
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @deprecated Use {@link #getResultSet()} instead, will be removed in Jaybird 7
+     */
+    @SuppressWarnings("removal")
+    @Deprecated
     @Override
     public ResultSet getCurrentResultSet() throws SQLException {
-        return currentRs;
+        return getResultSet();
     }
 
     @Override

src/main/org/firebirdsql/jdbc/FirebirdStatement.java

@@ -80,17 +80,17 @@ public interface FirebirdStatement extends Statement {
      * with this statement, otherwise <code>false</code>.
      */
     boolean hasOpenResultSet();
-    
+
     /**
-     * Get current result set. Behaviour of this method is similar to the 
-     * behavior of the {@link Statement#getResultSet()}, except that this method
-     * can be called as much as you like.
-     * 
-     * @return instance of {@link ResultSet} representing current result set
-     * or <code>null</code> if it is not available.
-     * 
-     * @throws SQLException if database access error happened.
+     * Get current result set. Behaviour of this method is similar to the behavior of the
+     * {@link Statement#getResultSet()}.
+     *
+     * @return instance of {@link ResultSet} representing current result set or {@code null} if it is not available.
+     * @throws SQLException
+     *         if a database access error happens
+     * @deprecated Use {@link #getResultSet()} instead, will be removed in Jaybird 7
      */
+    @Deprecated
     ResultSet getCurrentResultSet() throws SQLException;
 
     /**

src/test/org/firebirdsql/jdbc/FBStatementTest.java

@@ -1096,6 +1096,28 @@ void statementExecuteProcedureShouldNotTrim_729() throws Exception {
         }
     }
 
+    @Test
+    void getResultSetAfterExecuteQuery_sameResultSet() throws Exception {
+        try (Statement stmt = con.createStatement();
+             ResultSet rs = stmt.executeQuery("select 1 from rdb$database")) {
+            ResultSet sameRs = assertDoesNotThrow(stmt::getResultSet);
+
+            assertSame(rs, sameRs, "Expected ResultSet from getResultSet to be the same as from executeQuery");
+        }
+    }
+
+    @Test
+    void multipleGetResultSetCalls_sameResultSet() throws SQLException {
+        try (Statement stmt = con.createStatement()) {
+            assertTrue(stmt.execute("select 1 from rdb$database"), "Expected a result set as first result");
+
+            ResultSet rs = stmt.getResultSet();
+            ResultSet sameRs = assertDoesNotThrow(stmt::getResultSet);
+
+            assertSame(rs, sameRs, "Expected ResultSet from getResultSet to be the same as from previous getResultSet");
+        }
+    }
+
     private void prepareTestData() throws SQLException {
         executeCreateTable(con, CREATE_TABLE);