Package org.firebirdsql.gds.ng.fields

Class FieldDescriptor

java.lang.Object

org.firebirdsql.gds.ng.fields.FieldDescriptor

public final class FieldDescriptor
extends java.lang.Object

The class FieldDescriptor contains the column metadata of the XSQLVAR server data structure used to describe one column for input or output.

FieldDescriptor is an immutable type, the value of a field is maintained separately in RowValue.

Version:

3.0

Author:

Mark Rotteveel

Constructor Summary

Constructors

Constructor	Description
FieldDescriptor(int position, DatatypeCoder datatypeCoder, int type, int subType, int scale, int length, java.lang.String fieldName, java.lang.String tableAlias, java.lang.String originalName, java.lang.String originalTableName, java.lang.String ownerName)	Constructor for metadata FieldDescriptor.

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object obj)
int	getCharacterLength()	The length in characters of this field.
DatatypeCoder	getDatatypeCoder()
IEncodingFactory	getEncodingFactory()
java.lang.String	getFieldName()
int	getLength()
java.lang.String	getOriginalName()
java.lang.String	getOriginalTableName()
java.lang.String	getOwnerName()
int	getPosition()
int	getScale()
int	getSubType()
java.lang.String	getTableAlias()
int	getType()
int	hashCode()
boolean	isDbKey()	Determines if this is a db-key (RDB$DB_KEY) of a table.
boolean	isFbType(int fbType)	Check if the type of this field is the specified Firebird data type.
boolean	isNullable()
boolean	isVarying()
java.lang.String	toString()
boolean	typeEquals(FieldDescriptor other)	Limited equals that only checks if the data type in the provided field descriptor is the same as this descriptor.

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldDescriptor

public FieldDescriptor(int position,
                       DatatypeCoder datatypeCoder,
                       int type,
                       int subType,
                       int scale,
                       int length,
                       java.lang.String fieldName,
                       java.lang.String tableAlias,
                       java.lang.String originalName,
                       java.lang.String originalTableName,
                       java.lang.String ownerName)

Constructor for metadata FieldDescriptor.

Parameters:

position - Position of this field (0-based), or -1 if position is not known (eg for test code)

datatypeCoder - Instance of DatatypeCoder to use when decoding column data (note that another instance may be derived internally, which then will be returned by getDatatypeCoder())

type - Column SQL type

subType - Column subtype

scale - Column scale

length - Column defined length

fieldName - Column alias name

tableAlias - Column table alias

originalName - Column original name

originalTableName - Column original table

ownerName - Owner of the column/table

Method Detail

getPosition

public int getPosition()

Returns:

The 0-based position of this field (or -1)

getDatatypeCoder

public DatatypeCoder getDatatypeCoder()

Returns:

The DatatypeCoder to use when decoding field data.

getEncodingFactory

public IEncodingFactory getEncodingFactory()

Returns:

The IEncodingFactory for the associated connection.

getType

public int getType()

Returns:

The Firebird type of this field

getSubType

public int getSubType()

Returns:

The Firebird subtype of this field

getScale

public int getScale()

Returns:

The scale of this field

getLength

public int getLength()

Returns:

The declared (maximum) length of this field

getFieldName

public java.lang.String getFieldName()

Returns:

The (aliased) field name

getTableAlias

public java.lang.String getTableAlias()

Returns:

The (aliased) table name

getOriginalName

public java.lang.String getOriginalName()

Returns:

The original name of the field (eg the column name in the table)

getOriginalTableName

public java.lang.String getOriginalTableName()

Returns:

The original table name

getOwnerName

public java.lang.String getOwnerName()

Returns:

The owner

isVarying

public boolean isVarying()

Returns:

true if the type is variable length (ie ISCConstants.SQL_VARYING).

isFbType

public boolean isFbType(int fbType)

Check if the type of this field is the specified Firebird data type.

This method assumes the not-nullable data type is passed, on checking the nullable bit of getType() is set to 0.

Parameters:

fbType - One of the SQL_ data type identifier values

Returns:

true if the type is the same as the type of this field

isNullable

public boolean isNullable()

Returns:

true if this field is nullable.

isDbKey

public boolean isDbKey()

Determines if this is a db-key (RDB$DB_KEY) of a table.

NOTE: Technically it could also be a normal CHAR CHARACTER SET OCTETS column called DB_KEY.

Returns:

true if the field is a RDB$DB_KEY

Since:

4.0

getCharacterLength

public int getCharacterLength()

The length in characters of this field.

This takes into account the max bytes per character of the character set.

Returns:

Character length, or -1 for non-character types (including blobs)

typeEquals

public boolean typeEquals(FieldDescriptor other)

Limited equals that only checks if the data type in the provided field descriptor is the same as this descriptor.

The fields checked are:

• type
• subType
• scale
• length

Parameters:

other - Field descriptor to check

Returns:

true when other is not null and has the same type definition as this instance, false otherwise.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object