When the H2 parser fails to parse a SQL statement, throw a more specific exception that

contains extra information to make it possible for smart editors to do autocomplete.
Patch from Nicolas Fortin.

h2/src/docsrc/html/changelog.html

@@ -44,6 +44,8 @@ Change Log
 </li><li>Add a CONTAINS_UNCOMMITTED column to the SESSIONS metadata table, to allow detecting when rogue
     sessions are creating large transactions.
 </li><li>Some small fixes to the GEOMETRY support, patches by Nicolas Fortin.
+</li><li>When the H2 parser fails to parse a SQL statement, throw a more specific exception that
+    contains extra information to make it possible for smart editors to do autocomplete. Patch from Nicolas Fortin.
 </li></ul>
 
 <h2>Version 1.3.173 (2013-07-28)</h2>

h2/src/main/org/h2/api/JdbcParseSQLException.java

+/*
+ * Copyright 2004-2013 H2 Group. Multiple-Licensed under the H2 License,
+ * Version 1.0, and under the Eclipse Public License, Version 1.0
+ * (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.api;
+
+import java.util.List;
+import org.h2.jdbc.JdbcSQLException;
+
+/**
+ * A JDBC SQL Exception with additional parameters, it provides the syntax error
+ * position and expected token.
+ * <p>
+ * When the H2 parser encounters an error, it normally throws one of these
+ * exceptions. Clients may use this information to implement things like
+ * autocomplete in editors, or just better display of errors.
+ * 
+ * @author Nicolas Fortin, Atelier SIG, IRSTV FR CNRS 24888
+ */
+public class JdbcParseSQLException extends JdbcSQLException {
+    
+    private final List<String> expectedTokens;
+    private final int syntaxErrorPosition;
+
+    /**
+     * Creates a JdbcParseSQLException.
+     * 
+     * @param message the reason
+     * @param sql the SQL statement
+     * @param state the SQL state
+     * @param errorCode the error code
+     * @param cause the exception that was the reason for this exception
+     * @param stackTrace the stack trace
+     * @param expectedTokens H2 parser expected tokens
+     * @param syntaxErrorPosition Syntax error character index
+     */
+    public JdbcParseSQLException(String message, String sql, String state, int errorCode, Throwable cause,
+            String stackTrace, List<String> expectedTokens, int syntaxErrorPosition) {
+        super(message, sql, state, errorCode, cause, stackTrace);
+        this.expectedTokens = expectedTokens;
+        this.syntaxErrorPosition = syntaxErrorPosition;
+    }
+
+    /**
+     * H2 parser expected tokens
+     */
+    public List<String> getExpectedTokens() {
+        return expectedTokens;
+    }
+
+    /**
+     * Syntax error character position
+     */
+    public int getSyntaxErrorPosition() {
+        return syntaxErrorPosition;
+    }
+}

h2/src/main/org/h2/command/Parser.java

@@ -499,7 +499,7 @@ public class Parser {
             buff.appendExceptFirst(", ");
             buff.append(e);
         }
-        return DbException.getSyntaxError(sqlCommand, parseIndex, buff.toString());
+        return DbException.getSyntaxError(sqlCommand, parseIndex, buff.toString(), expectedList);
     }
 
     private Prepared parseBackup() {

h2/src/main/org/h2/message/DbException.java

@@ -11,9 +11,11 @@ import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.sql.SQLException;
 import java.text.MessageFormat;
+import java.util.List;
 import java.util.Locale;
-import java.util.Properties;
 import java.util.Map.Entry;
+import java.util.Properties;
+import org.h2.api.JdbcParseSQLException;
 import org.h2.constant.ErrorCode;
 import org.h2.jdbc.JdbcSQLException;
 import org.h2.util.SortedProperties;
@@ -192,8 +194,20 @@ public class DbException extends RuntimeException {
      * @return the exception
      */
     public static DbException getSyntaxError(String sql, int index, String expected) {
+        return getSyntaxError(sql, index, expected, java.util.Arrays.asList(expected));
+    }
+
+    /**
+     * Create a syntax error exception.
+     * 
+     * @param sql the SQL statement
+     * @param index the position of the error in the SQL statement
+     * @param expected the expected keyword(s) at the given position
+     * @return the exception
+     */
+    public static DbException getSyntaxError(String sql, int index, String message, List<String> expected) {
         sql = StringUtils.addAsterisk(sql, index);
-        return get(ErrorCode.SYNTAX_ERROR_2, sql, expected);
+        return new DbException(getParseJdbcSQLException(ErrorCode.SYNTAX_ERROR_2, null, index, expected, sql, message));
     }
 
     /**
@@ -326,9 +340,29 @@ public class DbException extends RuntimeException {
      * @return the SQLException object
      */
     private static JdbcSQLException getJdbcSQLException(int errorCode, Throwable cause, String... params) {
+        return getParseJdbcSQLException(errorCode, cause, 0, null, params);
+    }
+
+    /**
+     * Gets the SQL exception object for a specific error code.
+     * 
+     * @param errorCode the error code
+     * @param cause the cause of the exception
+     * @param syntaxErrorPosition Syntax error character index
+     * @param expectedTokens H2 parser expected tokens
+     * @param params the list of parameters of the message
+     * @return the SQLException object
+     */
+    private static JdbcSQLException getParseJdbcSQLException(int errorCode, Throwable cause, int syntaxErrorPosition,
+            List<String> expectedTokens, String... params) {
         String sqlstate = ErrorCode.getState(errorCode);
         String message = translate(sqlstate, params);
+        if (expectedTokens == null) {
             return new JdbcSQLException(message, null, sqlstate, errorCode, cause, null);
+        } else {
+            return new JdbcParseSQLException(message, null, sqlstate, errorCode, cause, null, expectedTokens,
+                    syntaxErrorPosition);
+        }
     }
 
     /**

h2/src/test/org/h2/test/jdbc/TestPreparedStatement.java

@@ -26,6 +26,7 @@ import java.util.GregorianCalendar;
 import java.util.SimpleTimeZone;
 import java.util.TimeZone;
 import java.util.UUID;
+import org.h2.api.JdbcParseSQLException;
 import org.h2.api.Trigger;
 import org.h2.constant.ErrorCode;
 import org.h2.test.TestBase;
@@ -86,6 +87,7 @@ public class TestPreparedStatement extends TestBase {
         testBlob(conn);
         testClob(conn);
         testParameterMetaData(conn);
+        testParseException(conn);
         conn.close();
         deleteDb("preparedStatement");
     }
@@ -1182,4 +1184,26 @@ public class TestPreparedStatement extends TestBase {
         assertTrue(!rs.next());
     }
 
+    private void testParseException(Connection conn) {
+        try {
+            conn.prepareStatement("SELECT * FROM");
+            fail();
+        } catch (JdbcParseSQLException ex) {
+            assertEquals(14, ex.getSyntaxErrorPosition());
+            assertEquals(new Object[] { "identifier" }, ex.getExpectedTokens().toArray());
+        } catch (SQLException ex) {
+            fail();
+        }
+        try {
+            conn.prepareStatement("ALTER");
+            fail();
+        } catch (JdbcParseSQLException ex) {
+            assertEquals(6, ex.getSyntaxErrorPosition());
+            assertEquals(new Object[] { "TABLE", "USER", "INDEX", "SCHEMA", "SEQUENCE", "VIEW" }, ex
+                    .getExpectedTokens().toArray());
+        } catch (SQLException ex) {
+            fail();
+        }
+    }
+    
 }