org.apache.empire.db
Class DBExpr

java.lang.Object
  org.apache.empire.db.DBObject
      org.apache.empire.db.DBExpr

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

DBCmdParam, DBColumnExpr, DBCommandExpr, DBCompareExpr, DBJoinExpr, DBOrderByExpr, DBRowSet, DBSetExpr

public abstract class DBExpr
extends DBObject

This abstract class is the base class for all database expression classes (e.g. DBAliasExpr or DBCalsExpr)

See Also:

Serialized Form

Field Summary

static long	CTX_ALIAS
static long	CTX_ALL
static long	CTX_DEFAULT
static long	CTX_FULLNAME
static long	CTX_NAME
static long	CTX_NOPARENTHESES
static long	CTX_VALUE

Constructor Summary

DBExpr()

Method Summary

abstract void	addReferencedColumns(Set<DBColumn> list) Internal function to obtain all DBColumnExpr-objects used by this expression.
abstract void	addSQL(StringBuilder buf, long context) Used to build the SQL command.
protected String	getObjectValue(DataType dataType, Object value, long context, String arraySep) Returns the sql representation of a value.
static Class	getValueClass(DataType type) Returns the java class type for a given dataType

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

getDatabase

Methods inherited from class java.lang.Object

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

Field Detail

CTX_DEFAULT

public static final long CTX_DEFAULT

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Constant Field Values

CTX_ALL

public static final long CTX_ALL

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Constant Field Values

CTX_NAME

public static final long CTX_NAME

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Constant Field Values

CTX_FULLNAME

public static final long CTX_FULLNAME

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Constant Field Values

CTX_VALUE

public static final long CTX_VALUE

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Constant Field Values

CTX_ALIAS

public static final long CTX_ALIAS

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Constant Field Values

CTX_NOPARENTHESES

public static final long CTX_NOPARENTHESES

See Also:

Constant Field Values

Constructor Detail

DBExpr

public DBExpr()

Method Detail

addSQL

public abstract void addSQL(StringBuilder buf,
                            long context)

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

Parameters:

buf - the string buffer used to build the sql command

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

addReferencedColumns

public abstract void addReferencedColumns(Set<DBColumn> list)

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

Parameters:

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

getObjectValue

protected String getObjectValue(DataType dataType,
                                Object value,
                                long context,
                                String arraySep)

Returns the sql representation of a value.

Parameters:

dataType - the DataType

value - an DBExpr object, array or a basis data type(e.g. int, String)

context - the context of the DBColumnExpr object

arraySep - the separator value

Returns:

the new SQL-Command

getValueClass

public static final Class getValueClass(DataType type)

Returns the java class type for a given dataType

Parameters:

type - the data type

Returns:

return the java class used for storing values of this dataType