org.apache.empire.db.expr.column

Class DBCalcExpr

java.lang.Object

org.apache.empire.db.DBObject

org.apache.empire.db.DBExpr

org.apache.empire.db.DBColumnExpr

org.apache.empire.db.expr.column.DBCalcExpr

All Implemented Interfaces:

Serializable, ColumnExpr

public class DBCalcExpr
extends DBColumnExpr

This class is used for performing calculations in SQL
It handles the mathematical operations ("+", "-", "*", "/") for the current column.

There is no need to explicitly create instances of this class.
Instead use DBColumnExpr.plus(Object), DBColumnExpr.minus(Object), DBColumnExpr.multiplyWith(Object), DBColumnExpr.divideBy(Object)

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.empire.db.DBColumnExpr

attributes, beanPropertyName, DBCOLATTR_TITLE, DBCOLATTR_TYPE, options

Fields inherited from class org.apache.empire.db.DBExpr

CTX_ALIAS, CTX_ALL, CTX_DEFAULT, CTX_FULLNAME, CTX_NAME, CTX_NOPARENTHESES, CTX_VALUE

Constructor Summary

Constructors

Constructor and Description
DBCalcExpr(DBColumnExpr expr, String op, Object value) Constructs a DBCalcExpr object Sets the mathematical operations ("+", "-", "*", "/") for the specified DBColumnExpr object and value.

Method Summary

Methods

Modifier and Type	Method and Description
void	addReferencedColumns(Set<DBColumn> list) Internal function to obtain all DBColumnExpr-objects used by this expression.
void	addSQL(StringBuilder buf, long context) Creates the SQL-Command adds the mathematical operations for the specified DBColumnExpr object and value to the.
Element	addXml(Element parent, long flags) This function set the specified mathematical operations to the XML tag.
DBDatabase	getDatabase() Returns the current DBDatabase object.
DataType	getDataType() Returns the data type: DBDataType.DECIMAL.
String	getName() Returns the given expression name.
DBColumn	getUpdateColumn() returns null
boolean	isAggregate() Always returns false since CalcExpressions cannot be aggregates.
String	toString()

Methods inherited from class org.apache.empire.db.DBColumnExpr

abs, append, as, as, asc, avg, cmp, coalesce, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, desc, detectDataType, divideBy, getAttribute, getBeanPropertyName, getControlType, getExprFromPhrase, getExprFromPhrase, getOptions, getSourceColumn, getTitle, in, indexOf, indexOf, indexOf, is, isBetween, isGreaterThan, isLessOrEqual, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, month, multiplyWith, notIn, notLike, nvl, parenthesis, plus, plus, replace, reverse, round, setAttribute, setBeanPropertyName, setControlType, setOptions, setTitle, substring, substring, substring, substring, substring, substring, sum, toChar, toChar, trim, trimLeft, trimRight, trunc, upper, when, year

Methods inherited from class org.apache.empire.db.DBExpr

getObjectValue, getValueClass

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DBCalcExpr

public DBCalcExpr(DBColumnExpr expr,
          String op,
          Object value)

Constructs a DBCalcExpr object Sets the mathematical operations ("+", "-", "*", "/")
for the specified DBColumnExpr object and value.

Parameters:

expr - an DBColumnExpr object, one column

op - the mathematical operation ("+", "-", "*" or "/")

value - the multiply, divide, summate or subtract value

Method Detail

getDatabase

public DBDatabase getDatabase()

Returns the current DBDatabase object.

Specified by:

getDatabase in class DBObject

Returns:

the current DBDatabase object

getDataType

public DataType getDataType()

Returns the data type: DBDataType.DECIMAL.

Specified by:

getDataType in interface ColumnExpr

Specified by:

getDataType in class DBColumnExpr

Returns:

the expressions data type

See Also:

DataType

getName

public String getName()

Returns the given expression name.

Specified by:

getName in interface ColumnExpr

Specified by:

getName in class DBColumnExpr

Returns:

the column name

addXml

public Element addXml(Element parent,
             long flags)

This function set the specified mathematical operations to the XML tag.

Specified by:

addXml in class DBColumnExpr

Parameters:

parent - the parent element to which to append the column description

flags - currently not used

Returns:

the XML tag (with the mathematical operations)

getUpdateColumn

public DBColumn getUpdateColumn()

returns null

Specified by:

getUpdateColumn in class DBColumnExpr

Returns:

the column to be used for updates if any.

isAggregate

public boolean isAggregate()

Always returns false since CalcExpressions cannot be aggregates.

Specified by:

isAggregate in class DBColumnExpr

Returns:

false

addReferencedColumns

public void addReferencedColumns(Set<DBColumn> list)

Description copied from class: DBExpr

Internal function to obtain all DBColumnExpr-objects used by this expression.

Specified by:

addReferencedColumns in class DBExpr

Parameters:

list - list to which all used column expressions must be added

See Also:

DBExpr.addReferencedColumns(Set)

addSQL

public void addSQL(StringBuilder buf,
          long context)

Creates the SQL-Command adds the mathematical operations for the specified DBColumnExpr object and value to the. SQL-Command

Specified by:

addSQL in class DBExpr

Parameters:

buf - the SQL statment

context - the current SQL-Command context

toString

public String toString()

Overrides:

toString in class Object