Package org.apache.empire.db.expr.column

Class DBDecodeExpr

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

org.apache.empire.db.expr.column.DBDecodeExpr

All Implemented Interfaces:

ColumnExpr, DBPreparable

public class DBDecodeExpr
extends DBAbstractFuncExpr

This class is used to decode a set of keys to the corresponding target values. For most drivers this will be performed by the "case ? when A then X else Y end" statement.

There is no need to explicitly create instances of this class.
Instead use DBColumnExpr.when(org.apache.empire.db.expr.compare.DBCompareExpr, Object)

Author:

doebele

Field Summary

Fields inherited from class org.apache.empire.db.expr.column.DBAbstractFuncExpr

dataType, expr, isAggregate, 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
DBDecodeExpr(DBColumnExpr expr, Map<?,?> valueMap, Object elseExpr, DataType dataType)	Constructs a DBDecodeExpr

Method Summary

Modifier and Type	Method	Description
void	addDecodeParts(DBSQLBuilder sql)
void	addReferencedColumns(Set<DBColumn> list)	Internal function to obtain all DBColumnExpr-objects used by this expression.
void	addSQL(DBSQLBuilder sql, long context)	Used to build the SQL command.
DBDecodeExpr	autoParam()	Automatically converts all literal values into Value expressions
Class<Enum<?>>	getEnumType()	Maybe an Enum...
protected String	getFunctionName()	returns the name of the function
DBColumn	getUpdateColumn()	Returns the DBColunm object.
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.expr.column.DBAbstractFuncExpr

addSQL, addXml, equals, getDatabase, getDataType, getDbms, getName, getRowSet, isAggregate

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.DBObject

checkParamNull

Methods inherited from class java.lang.Object

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

Constructor Details

DBDecodeExpr

public DBDecodeExpr(DBColumnExpr expr,
 Map<?,?> valueMap,
 Object elseExpr,
 DataType dataType)

Constructs a DBDecodeExpr

Parameters:

expr - the expression to be decoded

valueMap - a map of keys and values used for decoding

elseExpr - the expression returned if the condition is false (may be null)

dataType - the target data type

Method Details

getFunctionName

protected String getFunctionName()

Description copied from class: DBAbstractFuncExpr

returns the name of the function

Specified by:

getFunctionName in class DBAbstractFuncExpr

Returns:

the function name

getUpdateColumn

public DBColumn getUpdateColumn()

Description copied from class: DBAbstractFuncExpr

Returns the DBColunm object.

Specified by:

getUpdateColumn in interface ColumnExpr

Overrides:

getUpdateColumn in class DBAbstractFuncExpr

Returns:

the DBColunm object

getEnumType

public Class<Enum<?>> getEnumType()

Description copied from class: DBAbstractFuncExpr

Maybe an Enum...

Specified by:

getEnumType in interface ColumnExpr

Overrides:

getEnumType in class DBAbstractFuncExpr

Returns:

the enum type

autoParam

public DBDecodeExpr autoParam()

Automatically converts all literal values into Value expressions

Returns:

self (this)

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

Overrides:

prepareParams in class DBAbstractFuncExpr

Parameters:

cmd - the command to which to add the parameters

parent - the parent expression holding the value

addReferencedColumns

public void addReferencedColumns(Set<DBColumn> list)

Description copied from class: DBExpr

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

Overrides:

addReferencedColumns in class DBAbstractFuncExpr

Parameters:

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

See Also:

• DBExpr.addReferencedColumns(Set)

addSQL

public void addSQL(DBSQLBuilder sql,
 long context)

Description copied from class: DBExpr

Used to build the SQL command. SQL for this expression must be appended to StringBuilder.

Specified by:

addSQL in class DBExpr

Parameters:

sql - the string buffer used to build the sql command

context - context flag for this SQL-Command (see CTX_??? constants).

addDecodeParts

public void addDecodeParts(DBSQLBuilder sql)