#762 Remove restriction to only allow calls to getResultSet if the re…

…sult set was not returned yet

Deprecates FirebirdStatement.getCurrentResultSet.

src/docs/asciidoc/release_notes.adoc

@@ -901,6 +901,10 @@ Other drivers and tools simply send the requests for blob id `0` to the server,
 For consistency, we decided to let Jaybird handle it the same.
 +
 This change was also backported to Jaybird 5.0.3.
+* 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 call and returns `getResultSet`, and the `getCurrentResultSet` method has been deprecated for removal in Jaybird 7.
 * Fixed: The implementation of `Blob.getBytes(long, int)` threw a `SQLException` if the remaining bytes of the blob where less than the requested number of bytes (https://github.com/FirebirdSQL/jaybird/issues/767[#767])
 +
 The JDBC API specifies _"This `byte` array contains up to `length` consecutive bytes starting at position pos."_, so the implementation was changed to return up to `length` bytes, or the remaining actual blob length, whichever is shorter.
@@ -1437,6 +1441,9 @@ The following methods will be removed in Jaybird 7:
 It may get removed in Jaybird 7 or later.
 ** `getSupportedProtocols` -- use `getSupportedProtocolList()`.
 It may get removed in Jaybird 7 or later.
+* `FirebirdStatement`
+** `getCurrentResultSet()` -- use `getResultSet()`.
+Will be removed in Jaybird 7.
 
 [#removal-of-deprecated-classes-7]
 ===== Removal of deprecated classes

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

@@ -49,7 +49,6 @@ 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;
@@ -173,10 +172,7 @@ 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 {
@@ -248,17 +244,17 @@ 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 SQLNonTransientException("No resultset for sql", SQL_STATE_NO_RESULT_SET);
             }
 
-            getResultSet();
-            setRequiredTypes();
-
-            return getCurrentResultSet();
+            ResultSet rs = getResultSet();
+            setRequiredTypesInternal((FBResultSet) rs);
+            return rs;
         }
     }
 
@@ -296,7 +292,6 @@ 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()) {
@@ -478,7 +473,6 @@ public double getDouble(int parameterIndex) throws SQLException {
         return getAndAssertSingletonResultSet().getDouble(parameterIndex);
     }
 
-    @SuppressWarnings("deprecation")
     @Deprecated
     @Override
     public BigDecimal getBigDecimal(int parameterIndex, int scale) throws SQLException {
@@ -1109,14 +1103,6 @@ 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.
@@ -1129,28 +1115,11 @@ 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

@@ -537,26 +537,21 @@ public ResultSet getResultSet() throws SQLException {
     public ResultSet getResultSet(boolean metaDataQuery) throws  SQLException {
         if (fbStatement == null) {
             throw new SQLException("No statement was executed", SQL_STATE_INVALID_STATEMENT_ID);
-        }
-
-        if (cursorName != null) {
-            fbStatement.setCursorName(cursorName);
-        }
-
-        if (currentRs != null) {
-            throw new SQLException("Only one result set at a time/statement", SQL_STATE_GENERAL_ERROR);
+        } else if (currentRs != null) {
+            return currentRs;
         }
 
         // 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;
     }
@@ -832,9 +827,16 @@ void closeResultSet(boolean notifyListener, CompletionReason completionReason) t
         }
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @deprecated Use {@link #getResultSet()} instead, will be removed in Jaybird 7
+     */
+    @SuppressWarnings("removal")
+    @Deprecated(since = "6", forRemoval = true)
     @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(since = "6", forRemoval = true)
     ResultSet getCurrentResultSet() throws SQLException;
 
     /**

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

@@ -1121,6 +1121,28 @@ void psqlExceptionWithParametersRendering() throws Exception {
         }
     }
 
+    @Test
+    void getResultSetAfterExecuteQuery_sameResultSet() throws Exception {
+        try (var stmt = con.createStatement();
+             var rs = stmt.executeQuery("select 1 from rdb$database")) {
+            ResultSet sameRs = assertDoesNotThrow(stmt::getResultSet);
+
+            assertSame(rs, sameRs, "Expected ResultSet from getResultSet to be the same as from executeQuery");
+        }
+    }
+
+    @Test
+    void multipleGetResultSetCalls_sameResultSet() throws SQLException {
+        try (var stmt = con.createStatement()) {
+            assertTrue(stmt.execute("select 1 from rdb$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);