org.apache.empire.db.expr.column

Class DBAbstractFuncExpr

java.lang.Object

org.apache.empire.db.DBObject

org.apache.empire.db.DBExpr

org.apache.empire.db.DBColumnExpr

org.apache.empire.db.expr.column.DBAbstractFuncExpr

All Implemented Interfaces:

Serializable, ColumnExpr

Direct Known Subclasses:

DBConvertExpr, DBDecodeExpr, DBFuncExpr

public abstract class DBAbstractFuncExpr
extends DBColumnExpr

This implements some basic functionality for SQL functions based on a column expression

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected DataType	dataType
protected DBColumnExpr	expr
protected boolean	isAggregate
protected DBColumn	updateColumn

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
DBAbstractFuncExpr(DBColumnExpr expr, DBColumn updateColumn, boolean isAggregate, DataType dataType) Constructs a new DBFuncExpr object set the specified parameters to this object.

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 sql, String template, Object[] params, long context) Creates the SQL-Command adds a function to the SQL-Command.
Element	addXml(Element parent, long flags) Add a description of this column with relevant metadata to the supplied parent XML Element.
DBDatabase	getDatabase() Returns the current DBDatabase object.
protected DBDatabaseDriver	getDatabaseDriver() returns the Database driver or null if the Expression is not attached to an open database This function is intended for convenience only.
DataType	getDataType() Returns the data type of the DBColumnExpr object.
protected abstract String	getFunctionName() returns the name of the function
String	getName() Returns the column name.
DBColumn	getUpdateColumn() Returns the DBColunm object.
boolean	isAggregate() Returns whether the function is an aggegation function that combines multiple rows to one result row.
boolean	isMutuallyExclusive(DBAbstractFuncExpr other) check if other function is the same and applies to the same column

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

abs, append, as, as, asc, avg, ceiling, cmp, coalesce, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, decodeEnum, decodeSort, desc, divideBy, floor, format, getAttribute, getBeanPropertyName, getControlType, getExprFromPhrase, getExprFromPhrase, getOptions, getSourceColumn, getTitle, in, in, in, indexOf, indexOf, indexOf, is, isBetween, isGreaterThan, isLessOrEqual, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, modulo, month, multiplyWith, notIn, notIn, 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

addSQL, getObjectValue, getValueClass

Methods inherited from class java.lang.Object

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

Field Detail

expr

protected final DBColumnExpr expr

updateColumn

protected final DBColumn updateColumn

isAggregate

protected final boolean isAggregate

dataType

protected final DataType dataType

Constructor Detail

DBAbstractFuncExpr

public DBAbstractFuncExpr(DBColumnExpr expr,
                  DBColumn updateColumn,
                  boolean isAggregate,
                  DataType dataType)

Constructs a new DBFuncExpr object set the specified parameters to this object. Do not use directly - use any of the DBColumnExpr.??? factory functions instead!

Parameters:

expr - the DBColumnExpr object

updateColumn - optional update column if any. This parameter may be null

isAggregate - indicates whether the function is an aggregate function (sum, min, max, avg, ...)

dataType - indicates the data type of the function result

Method Detail

getFunctionName

protected abstract String getFunctionName()

returns the name of the function

Returns:

the function name

getDatabaseDriver

protected final DBDatabaseDriver getDatabaseDriver()

returns the Database driver or null if the Expression is not attached to an open database
This function is intended for convenience only.

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 of the DBColumnExpr object.

Specified by:

getDataType in interface ColumnExpr

Specified by:

getDataType in class DBColumnExpr

Returns:

the data type

See Also:

DataType

getName

public String getName()

Returns the column name.

Specified by:

getName in interface ColumnExpr

Specified by:

getName in class DBColumnExpr

Returns:

the column name

getUpdateColumn

public DBColumn getUpdateColumn()

Returns the DBColunm object.

Specified by:

getUpdateColumn in class DBColumnExpr

Returns:

the DBColunm object

isAggregate

public boolean isAggregate()

Returns whether the function is an aggegation function
that combines multiple rows to one result row.

Specified by:

isAggregate in class DBColumnExpr

Returns:

true if the function is an aggregate or false otherwise

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)

isMutuallyExclusive

public boolean isMutuallyExclusive(DBAbstractFuncExpr other)

check if other function is the same and applies to the same column

Parameters:

other -

Returns:

true if both functions are the same and on the same column or false otherwise

addSQL

public final void addSQL(StringBuilder sql,
          String template,
          Object[] params,
          long context)

Creates the SQL-Command adds a function to the SQL-Command. The sql function string is built from a string template. The template string must contain a ? which is a placeholder for the column expression.

Parameters:

sql - the SQL-Command

template - the function template string.

params - an array of function parameters

context - the current SQL-Command context

addXml

public Element addXml(Element parent,
             long flags)

Description copied from class: DBColumnExpr

Add a description of this column with relevant metadata to the supplied parent XML Element.

Specified by:

addXml in class DBColumnExpr

Parameters:

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

flags - currently not used

Returns:

the newly created child element