added SIGNAL function

h2/src/docsrc/help/help.csv

@@ -4013,6 +4013,14 @@ This function may be expensive since it has to load every page in the table.
 CALL DISK_SPACE_USED('my_table');
 "
 
+"Functions (System)","SIGNAL","
+SIGNAL(sqlState, message)
+","
+Throw an SQLException with the passed SQLState and reason.
+","
+CALL SIGNAL('23505', 'Duplicate user ID: ' || user_id);
+"
+
 "Functions (System)","FILE_READ","
 FILE_READ(fileNameString [,encodingString])
 ","

h2/src/main/org/h2/expression/Function.java

@@ -22,6 +22,7 @@ import java.util.Locale;
 import java.util.TimeZone;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
+
 import org.h2.api.ErrorCode;
 import org.h2.command.Command;
 import org.h2.command.Parser;
@@ -109,7 +110,9 @@ public class Function extends Expression implements FunctionCall {
     public static final int DATABASE = 150, USER = 151, CURRENT_USER = 152,
             IDENTITY = 153, SCOPE_IDENTITY = 154, AUTOCOMMIT = 155,
             READONLY = 156, DATABASE_PATH = 157, LOCK_TIMEOUT = 158,
-            DISK_SPACE_USED = 159;
+            DISK_SPACE_USED = 159, SIGNAL = 160;
+
+    private static final Pattern SIGNAL_PATTERN = Pattern.compile("[0-9A-Z]{5}");
 
     public static final int IFNULL = 200, CASEWHEN = 201, CONVERT = 202,
             CAST = 203, COALESCE = 204, NULLIF = 205, CASE = 206,
@@ -480,6 +483,7 @@ public class Function extends Expression implements FunctionCall {
                 VAR_ARGS, Value.NULL);
         addFunctionNotDeterministic("DISK_SPACE_USED", DISK_SPACE_USED,
                 1, Value.LONG);
+        addFunctionWithNull("SIGNAL", SIGNAL, 2, Value.NULL);
         addFunction("H2VERSION", H2VERSION, 0, Value.STRING);
 
         // TableFunction
@@ -1705,6 +1709,13 @@ public class Function extends Expression implements FunctionCall {
             result = session.getVariable(args[0].getSchemaName() + "." +
                     args[0].getTableName() + "." + args[0].getColumnName());
             break;
+        case SIGNAL: {
+            String sqlState = v0.getString();
+            if (sqlState.startsWith("00") || !SIGNAL_PATTERN.matcher(sqlState).matches())
+                throw DbException.getInvalidValueException("SQLSTATE", sqlState);
+            String msgText = v1.getString();
+            throw DbException.fromUser(sqlState, msgText);
+        }
         default:
             throw DbException.throwInternalError("type=" + info.type);
         }

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

@@ -179,6 +179,17 @@ public class DbException extends RuntimeException {
         return new DbException(getJdbcSQLException(errorCode, null, params));
     }
 
+    /**
+     * Create a database exception for an arbitrary SQLState.
+     *
+     * @param sqlstate the state to use
+     * @param message the message to use
+     * @return the exception
+     */
+    public static DbException fromUser(String sqlstate, String message) {
+        return new DbException(getJdbcSQLException(sqlstate, message));
+    }
+
     /**
      * Create a syntax error exception.
      *
@@ -345,6 +356,11 @@ public class DbException extends RuntimeException {
         return new JdbcSQLException(message, null, sqlstate, errorCode, cause, null);
     }
 
+    private static JdbcSQLException getJdbcSQLException(String sqlstate, String message) {
+        // do not translate as sqlstate is arbitrary : avoid "message not found"
+        return new JdbcSQLException(message, null, sqlstate, 0, null, null);
+    }
+
     /**
      * Convert an exception to an IO exception.
      *

h2/src/test/org/h2/test/db/TestFunctions.java

@@ -38,6 +38,7 @@ import java.util.Locale;
 import java.util.Properties;
 import java.util.TimeZone;
 import java.util.UUID;
+
 import org.h2.api.Aggregate;
 import org.h2.api.AggregateFunction;
 import org.h2.api.ErrorCode;
@@ -119,6 +120,7 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         testThatCurrentTimestampUpdatesOutsideATransaction();
         testAnnotationProcessorsOutput();
         testRound();
+        testSignal();
 
         deleteDb("functions");
     }
@@ -2037,6 +2039,26 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         conn.close();
     }
 
+    private void testSignal() throws SQLException {
+        deleteDb("functions");
+
+        Connection conn = getConnection("functions");
+        Statement stat = conn.createStatement();
+
+        assertThrows(ErrorCode.INVALID_VALUE_2, stat).execute("select signal('00145', 'success class is invalid')");
+        assertThrows(ErrorCode.INVALID_VALUE_2, stat).execute("select signal('foo', 'SQLSTATE has 5 chars')");
+        assertThrows(ErrorCode.INVALID_VALUE_2, stat).execute("select signal('Ab123', 'SQLSTATE has only digits or upper-case letters')");
+        try {
+            stat.execute("select signal('AB123', 'some custom error')");
+            fail("Should have thrown");
+        } catch (SQLException e) {
+            assertEquals("AB123", e.getSQLState());
+            assertContains(e.getMessage(), "some custom error");
+        }
+
+        conn.close();
+    }
+
     private void testThatCurrentTimestampIsSane() throws SQLException,
             ParseException {
         deleteDb("functions");