expression.java

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     * @param elist expression list
     */
    void getEquiJoinColumns(TableFilter filter, boolean[] columns,
                            Expression[] elist) {

        if (eArg != null) {
            eArg.getEquiJoinColumns(filter, columns, elist);
        }

        if (eArg2 != null) {
            eArg2.getEquiJoinColumns(filter, columns, elist);
        }

        if (exprType == EQUAL) {
            if (eArg.tableFilter == eArg2.tableFilter) {
                return;
            }

            // an elist element may be set more than once - OK
            if (eArg.tableFilter == filter) {
                if (eArg2.exprType == COLUMN || eArg2.exprType == VALUE) {
                    columns[eArg.columnIndex] = true;
                    elist[eArg.columnIndex]   = eArg2;
                }

                return;
            }

            if (eArg2.tableFilter == filter) {
                if (eArg.exprType == COLUMN || eArg.exprType == VALUE) {
                    columns[eArg2.columnIndex] = true;
                    elist[eArg2.columnIndex]   = eArg;
                }
            }
        }
    }

    /**
     * Find a table filter with the given table alias
     */
    TableFilter findTableFilter(TableFilter[] list) {

        for (int t = 0; t < list.length; t++) {
            TableFilter f = list[t];

            if (schema == null
                    || f.filterTable.getSchemaName().equals(schema)) {
                if (f.getName().equals(tableName)) {
                    return f;
                }
            }
        }

        return null;
    }

    /**
     * Resolve the table names for columns
     *
     * @param f table filter
     *
     * @throws HsqlException
     */
    void resolveTables(TableFilter f) throws HsqlException {

        if (isParam || f == null || exprType == Expression.VALUE) {
            return;
        }

        if (eArg != null) {
            eArg.resolveTables(f);
        }

        if (eArg2 != null) {
            eArg2.resolveTables(f);
        }

        switch (exprType) {

            case COLUMN :
                if (tableFilter != null) {
                    break;
                }

                String filterName = f.getName();

                if (tableName == null || tableName.equals(filterName)) {
                    Table table = f.getTable();
                    int   i     = table.findColumn(columnName);

                    if (i != -1) {
                        tableFilter = f;
                        columnIndex = i;
                        tableName   = filterName;

                        setTableColumnAttributes(table, i);

                        // COLUMN is leaf; we are done
                        return;
                    }
                }
                break;

            case QUERY :

                // we now (1_7_2_ALPHA_R) resolve independently first, then
                // resolve in the enclosing context
                if (subQuery != null) {
                    subQuery.select.resolveTablesUnion(f);
                }
                break;

            case FUNCTION :
                if (function != null) {
                    function.resolveTables(f);
                }
                break;

            case ALL :
            case ANY :
                break;

            case IN :
                if (eArg2.exprType != QUERY) {
                    Expression[] vl = eArg2.valueList;

                    for (int i = 0; i < vl.length; i++) {
                        vl[i].resolveTables(f);
                    }
                }
                break;

            default :
        }
    }

    /**
     * For CASE WHEN and its special cases section 9.3 of the SQL standard
     * on type aggregation should be implemented.
     */
    int getCaseWhenType(Session session) throws HsqlException {

        /*
            find data type in condition
            int type = eArg.eArg.getDataType();
            then recurse on eArg2

        */
        return eArg2.dataType;
    }

    void resolveTypes(Session session) throws HsqlException {

        if (isParam) {
            return;
        }

        if (eArg != null) {
            eArg.resolveTypes(session);
        }

        if (eArg2 != null) {
            eArg2.resolveTypes(session);
        }

        switch (exprType) {

            case VALUE :
                if (dataType == Types.BOOLEAN && valueData != null) {
                    dataType = 0;
                    exprType = ((Boolean) valueData).booleanValue() ? TRUE
                                                                    : FALSE;
                }
                break;

            case COLUMN :
                break;

            case FUNCTION :
                function.resolveType(session);

                dataType = function.getReturnType();
                break;

            case QUERY : {
                subQuery.select.resolveTypes(session);

                dataType = subQuery.select.exprColumns[0].dataType;

                break;
            }
            case NEGATE :
                if (eArg.isParam) {
                    throw Trace.error(Trace.UNRESOLVED_PARAMETER_TYPE,
                                      Trace.Expression_resolveTypes1);
                }

                dataType = eArg.dataType;

                if (isFixedConstant()) {
                    valueData = getValue(session, dataType);
                    eArg      = null;
                    exprType  = VALUE;
                }
                break;

            case ADD :

                // concat using + operator
                // non-standard concat operator to be deprecated
                if (Types.isCharacterType(eArg.dataType)
                        || Types.isCharacterType(eArg2.dataType)) {
                    exprType = Expression.CONCAT;
                    dataType = Types.VARCHAR;

                    if (isFixedConstant()) {
                        valueData = getValue(session, dataType);
                        eArg      = null;
                        eArg2     = null;
                        exprType  = VALUE;
                    } else {
                        if (eArg.isParam) {
                            eArg.dataType = Types.VARCHAR;
                        }

                        if (eArg2.isParam) {
                            eArg2.dataType = Types.VARCHAR;
                        }
                    }

                    break;
                }
            case SUBTRACT :
            case MULTIPLY :
            case DIVIDE :
                if (eArg.isParam && eArg2.isParam) {
                    throw Trace.error(Trace.UNRESOLVED_PARAMETER_TYPE,
                                      Trace.Expression_resolveTypes2);
                }

                if (isFixedConstant()) {
                    dataType = Column.getCombinedNumberType(eArg.dataType,
                            eArg2.dataType, exprType);
                    valueData = getValue(session, dataType);
                    eArg      = null;
                    eArg2     = null;
                    exprType  = VALUE;
                } else {
                    if (eArg.isParam) {
                        eArg.dataType = eArg2.dataType;
                    } else if (eArg2.isParam) {
                        eArg2.dataType = eArg.dataType;
                    }

                    // fredt@users 20011010 - patch 442993 by fredt
                    dataType = Column.getCombinedNumberType(eArg.dataType,
                            eArg2.dataType, exprType);
                }
                break;

            case CONCAT :
                dataType = Types.VARCHAR;

                if (isFixedConstant()) {
                    valueData = getValue(session, dataType);
                    eArg      = null;
                    eArg2     = null;
                    exprType  = VALUE;
                } else {
                    if (eArg.isParam) {
                        eArg.dataType = Types.VARCHAR;
                    }

                    if (eArg2.isParam) {
                        eArg2.dataType = Types.VARCHAR;
                    }
                }
                break;

            case EQUAL :
            case BIGGER_EQUAL :
            case BIGGER :
            case SMALLER :
            case SMALLER_EQUAL :
            case NOT_EQUAL :
                if (eArg.isParam && eArg2.isParam) {
                    throw Trace.error(Trace.UNRESOLVED_PARAMETER_TYPE,
                                      Trace.Expression_resolveTypes3);
                }

                if (isFixedConditional()) {
                    Boolean result = test(session);

                    if (result == null) {
                        setNull();
                    } else if (result.booleanValue()) {
                        exprType = TRUE;
                    } else {
                        exprType = FALSE;
                    }

                    eArg  = null;
                    eArg2 = null;
                } else if (eArg.isParam) {
                    eArg.dataType = eArg2.dataType == Types.NULL
                                    ? Types.VARCHAR
                                    : eArg2.dataType;

                    if (eArg2.exprType == COLUMN) {
                        eArg.setTableColumnAttributes(eArg2);
                    }
                } else if (eArg2.isParam) {
                    eArg2.dataType = eArg.dataType == Types.NULL
                                     ? Types.VARCHAR
                                     : eArg.dataType;

                    if (eArg.exprType == COLUMN) {
                        eArg2.setTableColumnAttributes(eArg);
                    }
                }

                dataType = Types.BOOLEAN;
                break;

            case LIKE :
                resolveTypeForLike(session);

                dataType = Types.BOOLEAN;
                break;

            case AND : {
                boolean argFixed  = eArg.isFixedConditional();
                boolean arg2Fixed = eArg2.isFixedConditional();
                Boolean arg       = argFixed ? (eArg.test(session))
                                             : null;
                Boolean arg2      = arg2Fixed ? eArg2.test(session)
                                              : null;

                if (argFixed && arg2Fixed) {
                    if (arg == null || arg2 == null) {
                        setNull();
                    } else {
                        exprType = arg.booleanValue() && arg2.booleanValue()
                                   ? TRUE
                                   : FALSE;
                        eArg  = null;
                        eArg2 = null;
                    }
                } else if ((argFixed &&!Boolean.TRUE.equals(arg))
                           || (arg2Fixed &&!Boolean.TRUE.equals(arg2))) {
                    exprType = FALSE;
                    eArg     = null;
                    eArg2    = null;
                } else {
                    if (eArg.isParam) {
                        eArg.dataType = Types.BOOLEAN;
                    }

                    if (eArg2.isParam) {
                        eArg2.dataType = Types.BOOLEAN;
                    }
                }

                dataType = Types.BOOLEAN;

                break;
            }
            case OR : {
                boolean argFixed  = eArg.isFixedConditional();
                boolean arg2Fixed = eArg2.isFixedConditional();
                Boolean arg       = argFixed ? (eArg.test(session))
                                             : null;
                Boolean arg2      = arg2Fixed ? eArg2.test(session)
                                              : null;

                if (argFixed && arg2Fixed) {
                    if (arg == null || arg2 == null) {
                        setNull();
                    } else {
                        exprType = arg.booleanValue() || arg2.booleanValue()
                                   ? TRUE
                                   : FALSE;
                        eArg  = null;
                        eArg2 = null;
                    }
                } else if ((argFixed && Boolean.TRUE.equals(arg))
                           || (arg2Fixed && Boolean.TRUE.equals(arg2))) {
                    exprType = TRUE;
                    eArg     = null;
                    eArg2    = null;
                } else {
                    if (eArg.isParam) {
                        eArg.dataType = Types.BOOLEAN;
                    }

                    if (eArg2.isParam) {
                        eArg2.dataType = Types.BOOLEAN;
                    }
                }

                dataType = Types.BOOLEAN;

                break;
            }
            case IS_NULL :
                if (isFixedConditional()) {
                    exprType = Boolean.TRUE.equals(test(session)) ? TRUE
                                                                  : FALSE;
                    eArg     = null;
                } else if (eArg.dataType == Types.NULL) {
                    eArg.dataType = Types.VARCHAR;
                }

                dataType = Types.BOOLEAN;
                break;

            case NOT :
                if (isFixedConditional()) {
                    Boolean arg = test(session);

                    if (arg == null) {
                        setNull();
                    } else {
                        exprType = arg.booleanValue() ? TRUE
                                                      : FALSE;
                        eArg     = null;
                    }
                } else if (eArg.isParam) {
                    eArg.dataType = Types.BOOLEAN;
                }

                dataType = Types.BOOLEAN;
                break;

            case ALL :
            case ANY :
                dataType = eArg.dataType;
                break;

            case IN :
                resolveTypeForIn(session);

                dataType = Types.BOOLEAN;
                break;

            case EXISTS :

                // NOTE: no such thing as a param arg if expression is EXISTS
                // Also, cannot detect if result is fixed value
                dataType = Types.BOOLEAN;
                break;

            /** @todo fredt - set the correct return type */
            case COUNT :
                if (eArg.isParam) {
                    throw Trace.error(Trace.UNRESOLVED_PARAMETER_TYPE,
                                      Trace.Express