Package 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:

ColumnExpr, DBPreparable

Direct Known Subclasses:

DBCoalesceExpr, DBConcatFuncExpr, DBConvertExpr, DBDecodeExpr, DBFuncExpr, PostgresFuncExpr

public abstract class DBAbstractFuncExpr
extends DBColumnExpr
implements DBPreparable

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

Field Summary

Fields

Modifier and Type	Field	Description
protected final DataType	dataType
protected final DBColumnExpr	expr
protected final boolean	isAggregate
protected static final org.slf4j.Logger	log

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

attributes, beanPropertyName, options

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

CTX_ALIAS, CTX_ALL, CTX_DEFAULT, CTX_FULLNAME, CTX_NAME, CTX_NOPARENTHESIS, CTX_VALUE

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
void	addReferencedColumns(Set<DBColumn> list)	Internal function to obtain all DBColumnExpr-objects used by this expression.
final void	addSQL(DBSQLBuilder 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.
boolean	equals(Object other)	Returns true if other is equal to this expression
final DBDatabase	getDatabase()	Returns the current DBDatabase object.
DataType	getDataType()	Returns the data type of the DBColumnExpr object.
protected DBMSHandler	getDbms()	returns the Database dbms or null if the Expression is not attached to an open database This function is intended for convenience only.
Class<Enum<?>>	getEnumType()	Maybe an Enum...
protected abstract String	getFunctionName()	returns the name of the function
String	getName()	Returns the column name.
DBRowSet	getRowSet()	Returns the underlying rowset
DBColumn	getUpdateColumn()	Returns the DBColunm object.
boolean	isAggregate()	Returns whether the function is an aggegation function that combines multiple rows to one result row.
void	prepareParams(DBCommand cmd, DBExpr parent)	Prepares an expression for a query This function is called by DBCommand in order to add values as query parameters instead of being literally included in the sql statement Please Note: This function is internally called.

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

abs, aggregate, append, as, as, asc, avg, ceiling, cmp, coalesce, concat, concat, contains, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, decodeEnum, decodeSort, desc, divideBy, floor, format, function, getAttribute, getAttribute, getBeanPropertyName, getControlType, getDefaultSortOrder, getExprFromPhrase, getExprFromPhrase, getIgnoreCaseExpr, getJavaType, getNumberType, getOptions, getSourceColumn, getTitle, in, in, in, indexOf, indexOf, indexOf, is, isBetween, isCaseSensitive, isGreaterThan, isLessOrEqual, isLiteralValue, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, modulo, month, multiplyWith, notContains, notIn, notIn, notIn, notLike, nvl, on, parenthesis, plus, plus, prepend, qualified, replace, reverse, round, setAttribute, setBeanPropertyName, setControlType, setDefaultSortOrder, setOptions, setTitle, stringAgg, stringAgg, substring, substring, substring, substring, substring, substring, sum, toChar, toChar, toString, trim, trimLeft, trimRight, trunc, upper, when, year

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

addSQL

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

checkParamNull

Methods inherited from class java.lang.Object

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

Field Details

log

protected static final org.slf4j.Logger log

expr

protected final DBColumnExpr expr

isAggregate

protected final boolean isAggregate

dataType

protected final DataType dataType

Constructor Details

DBAbstractFuncExpr

public DBAbstractFuncExpr(DBColumnExpr expr,
 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

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

dataType - indicates the data type of the function result

Method Details

getFunctionName

protected abstract String getFunctionName()

returns the name of the function

Returns:

the function name

getDbms

protected DBMSHandler getDbms()

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

Returns:

the dbms handler

getDatabase

public final 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

getEnumType

public Class<Enum<?>> getEnumType()

Maybe an Enum...

Specified by:

getEnumType in interface ColumnExpr

Returns:

the enum type

getName

public String getName()

Returns the column name.

Specified by:

getName in interface ColumnExpr

Specified by:

getName in class DBColumnExpr

Returns:

the column name

getRowSet

public DBRowSet getRowSet()

Returns the underlying rowset

Specified by:

getRowSet in class DBColumnExpr

Returns:

a column used for this expression

getUpdateColumn

public DBColumn getUpdateColumn()

Returns the DBColunm object.

Specified by:

getUpdateColumn in interface ColumnExpr

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)

equals

public boolean equals(Object other)

Returns true if other is equal to this expression

Overrides:

equals in class Object

prepareParams

public void prepareParams(DBCommand cmd,
 DBExpr parent)

Description copied from interface: DBPreparable

Prepares an expression for a query This function is called by DBCommand in order to add values as query parameters instead of being literally included in the sql statement Please Note: This function is internally called. Do not call yourself!

Specified by:

prepareParams in interface DBPreparable

Parameters:

cmd - the command to which to add the parameters

parent - the parent expression holding the value

addSQL

public final void addSQL(DBSQLBuilder 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