function.java

非常棒的java数据库

    }

    public static Function getFunction(Database database, String name) throws SQLException {
        FunctionInfo info = getFunctionInfo(name);
        if (info == null) {
            return null;
        }
        switch(info.type) {
        case TABLE:
        case TABLE_DISTINCT:
            return new TableFunction(database, info);
        default:
            return new Function(database, info);
        }
    }

    protected Function(Database database, FunctionInfo info) {
        this.database = database;
        this.info = info;
        if (info.parameterCount == VAR_ARGS) {
            varArgs = new ObjectArray();
        } else {
            args = new Expression[info.parameterCount];
        }
    }

    public void setParameter(int index, Expression param) throws SQLException {
        if (varArgs != null) {
            varArgs.add(param);
        } else {
            if (index >= args.length) {
                throw Message.getSQLException(ErrorCode.INVALID_PARAMETER_COUNT_2, new String[] { info.name,
                        "" + args.length });
            }
            args[index] = param;
        }
    }

    private strictfp double log10(double value) {
        return roundmagic(StrictMath.log(value) / StrictMath.log(10));
    }

    public Value getValue(Session session) throws SQLException {
        return getValueWithArgs(session, args);
    }

    private Value getNullOrValue(Session session, Expression[] x, int i) throws SQLException {
        if (i < x.length) {
            Expression e = x[i];
            if (e != null) {
                return e.getValue(session);
            }
        }
        return null;
    }

    private Value getSimpleValue(Session session, Value v0, Expression[] args) throws SQLException {
        Value result;
        switch (info.type) {
        case ABS:
            result = v0.getSignum() > 0 ? v0 : v0.negate();
            break;
        case ACOS:
            result = ValueDouble.get(Math.acos(v0.getDouble()));
            break;
        case ASIN:
            result = ValueDouble.get(Math.asin(v0.getDouble()));
            break;
        case ATAN:
            result = ValueDouble.get(Math.atan(v0.getDouble()));
            break;
        case CEILING:
            result = ValueDouble.get(Math.ceil(v0.getDouble()));
            break;
        case COS:
            result = ValueDouble.get(Math.cos(v0.getDouble()));
            break;
        case COT: {
            double d = Math.tan(v0.getDouble());
            if (d == 0.0) {
                throw Message.getSQLException(ErrorCode.DIVISION_BY_ZERO_1, getSQL());
            }
            result = ValueDouble.get(1. / d);
            break;
        }
        case DEGREES:
            result = ValueDouble.get(Math.toDegrees(v0.getDouble()));
            break;
        case EXP:
            result = ValueDouble.get(Math.exp(v0.getDouble()));
            break;
        case FLOOR:
            result = ValueDouble.get(Math.floor(v0.getDouble()));
            break;
        case LOG:
            result = ValueDouble.get(Math.log(v0.getDouble()));
            break;
        case LOG10:
            result = ValueDouble.get(log10(v0.getDouble()));
            break;
        case PI:
            result = ValueDouble.get(Math.PI);
            break;
        case RADIANS:
            result = ValueDouble.get(Math.toRadians(v0.getDouble()));
            break;
        case RAND: {
            if (v0 != null) {
                session.getRandom().setSeed(v0.getInt());
            }
            // TODO function rand: if seed value is set,
            // return a random value? probably yes
            result = ValueDouble.get(session.getRandom().nextDouble());
            break;
        }
        case ROUNDMAGIC:
            result = ValueDouble.get(roundmagic(v0.getDouble()));
            break;
        case SIGN:
            result = ValueInt.get(v0.getSignum());
            break;
        case SIN:
            result = ValueDouble.get(Math.sin(v0.getDouble()));
            break;
        case SQRT:
            result = ValueDouble.get(Math.sqrt(v0.getDouble()));
            break;
        case TAN:
            result = ValueDouble.get(Math.tan(v0.getDouble()));
            break;
        case SECURE_RAND:
            result = ValueBytes.getNoCopy(RandomUtils.getSecureBytes(v0.getInt()));
            break;
        case EXPAND:
            result = ValueBytes.getNoCopy(CompressTool.getInstance().expand(v0.getBytesNoCopy()));
            break;
        case ZERO:
            result = ValueInt.get(0);
            break;
        case RANDOM_UUID:
            result = ValueUuid.getNewRandom();
            break;
            // string
        case ASCII: {
            String s = v0.getString();
            if (s.length() == 0) {
                result = ValueNull.INSTANCE;
            } else {
                result = ValueInt.get(s.charAt(0));
            }
            break;
        }
        case BIT_LENGTH:
            result = ValueInt.get(16 * length(v0));
            break;
        case CHAR:
            result = ValueString.get(String.valueOf((char) v0.getInt()));
            break;
        case CHAR_LENGTH:
        case LENGTH:
            result = ValueInt.get(length(v0));
            break;
        case OCTET_LENGTH:
            result = ValueInt.get(2 * length(v0));
            break;
        case CONCAT: {
            result = ValueNull.INSTANCE;
            for (int i = 0; i < args.length; i++) {
                Value v = args[i].getValue(session);
                if (v == ValueNull.INSTANCE) {
                    continue;
                }
                if (result == ValueNull.INSTANCE) {
                    result = v;
                } else {
                    result = ValueString.get(result.getString().concat(v.getString()));
                }
            }
            break;
        }
        case HEXTORAW:
            result = ValueString.get(hexToRaw(v0.getString()));
            break;
        case LOWER:
        case LCASE:
            // TODO this is locale specific, need to document or provide a way
            // to set the locale
            result = ValueString.get(v0.getString().toLowerCase());
            break;
        case RAWTOHEX:
            result = ValueString.get(rawToHex(v0.getString()));
            break;
        case SOUNDEX:
            result = ValueString.get(getSoundex(v0.getString()));
            break;
        case SPACE: {
            // TODO DOS attacks: limit len?
            int len = Math.max(0, v0.getInt());
            char[] chars = new char[len];
            for (int i = len - 1; i >= 0; i--) {
                chars[i] = ' ';
            }
            result = ValueString.get(new String(chars));
            break;
        }
        case UPPER:
        case UCASE:
            // TODO this is locale specific, need to document or provide a way
            // to set the locale
            result = ValueString.get(v0.getString().toUpperCase());
            break;
        case STRINGENCODE:
            result = ValueString.get(StringUtils.javaEncode(v0.getString()));
            break;
        case STRINGDECODE:
            result = ValueString.get(StringUtils.javaDecode(v0.getString()));
            break;
        case STRINGTOUTF8:
            result = ValueBytes.getNoCopy(StringUtils.utf8Encode(v0.getString()));
            break;
        case UTF8TOSTRING:
            result = ValueString.get(StringUtils.utf8Decode(v0.getBytesNoCopy()));
            break;
        case XMLCOMMENT:
            result = ValueString.get(StringUtils.xmlComment(v0.getString()));
            break;
        case XMLCDATA:
            result = ValueString.get(StringUtils.xmlCData(v0.getString()));
            break;
        case XMLSTARTDOC:
            result = ValueString.get(StringUtils.xmlStartDoc());
            break;
        case XMLTEXT:
            result = ValueString.get(StringUtils.xmlText(v0.getString()));
            break;
        case DAYNAME: {
            synchronized (FORMAT_DAYNAME) {
                result = ValueString.get(FORMAT_DAYNAME.format(v0.getDateNoCopy()));
            }
            break;
        }
        case DAYOFMONTH:
            result = ValueInt.get(getDatePart(v0.getTimestampNoCopy(), Calendar.DAY_OF_MONTH));
            break;
        case DAYOFWEEK:
            result = ValueInt.get(getDatePart(v0.getTimestampNoCopy(), Calendar.DAY_OF_WEEK));
            break;
        case DAYOFYEAR:
            result = ValueInt.get(getDatePart(v0.getTimestampNoCopy(), Calendar.DAY_OF_YEAR));
            break;
        case HOUR:
            result = ValueInt.get(getDatePart(v0.getTimestampNoCopy(), Calendar.HOUR_OF_DAY));
            break;
        case MINUTE:
            result = ValueInt.get(getDatePart(v0.getTimestampNoCopy(), Calendar.MINUTE));
            break;
        case MONTH:
            result = ValueInt.get(getDatePart(v0.getTimestampNoCopy(), Calendar.MONTH));
            break;
        case MONTHNAME: {
            synchronized (FORMAT_MONTHNAME) {
                result = ValueString.get(FORMAT_MONTHNAME.format(v0.getDateNoCopy()));
            }
            break;
        }
        case QUARTER:
            result = ValueInt.get((getDatePart(v0.getTimestamp(), Calendar.MONTH) - 1) / 3 + 1);
            break;
        case SECOND:
            result = ValueInt.get(getDatePart(v0.getTimestamp(), Calendar.SECOND));
            break;
        case WEEK:
            result = ValueInt.get(getDatePart(v0.getTimestamp(), Calendar.WEEK_OF_YEAR));
            break;
        case YEAR:
            result = ValueInt.get(getDatePart(v0.getTimestamp(), Calendar.YEAR));
            break;
        case CURDATE:
        case CURRENT_DATE:
            // need to normalize
            result = ValueDate.get(new Date(System.currentTimeMillis()));
            break;
        case CURTIME:
        case CURRENT_TIME:
            // need to normalize
            result = ValueTime.get(new Time(System.currentTimeMillis()));
            break;
        case NOW:
        case CURRENT_TIMESTAMP: {
            ValueTimestamp vt = ValueTimestamp.getNoCopy(new Timestamp(System.currentTimeMillis()));
            if (v0 != null) {
                Mode mode = database.getMode();
                vt = (ValueTimestamp) vt.convertScale(mode.convertOnlyToSmallerScale, v0.getInt());
            }
            result = vt;
            break;
        }
        case DATABASE:
            result = ValueString.get(database.getShortName());
            break;
        case USER:
        case CURRENT_USER:
            result = ValueString.get(session.getUser().getName());
            break;
        case IDENTITY:
            result = session.getLastIdentity();
            break;
        case AUTOCOMMIT:
            result = ValueBoolean.get(session.getAutoCommit());
            break;
        case READONLY:
            result = ValueBoolean.get(database.getReadOnly());
            break;
        case DATABASE_PATH: {
            String path = database.getDatabasePath();
            result = path == null ? (Value) ValueNull.INSTANCE : ValueString.get(path);
            break;
        }
        case LOCK_TIMEOUT:
            result = ValueInt.get(session.getLockTimeout());
            break;
        case CAST:
        case CONVERT: {
            v0 = v0.convertTo(dataType);
            Mode mode = database.getMode();