Class UserDefinedTypeIdImpl

java.lang.Object

org.apache.derby.catalog.types.BaseTypeIdImpl

org.apache.derby.catalog.types.UserDefinedTypeIdImpl

All Implemented Interfaces:

Externalizable, Serializable, Formatable, TypedFormat

public class UserDefinedTypeIdImpl
extends BaseTypeIdImpl

This type id describes a user defined type. There are 2 kinds of user defined types in Derby:

• Old-fashioned - In the original Cloudscape code, it was possible to declare a column's type to be the name of a Java class. Unlike ANSI UDTs, these user defined types were not schema objects themselves and they didn't have schema-qualified names. Some of the system tables have columns whose datatypes are old-fashioned user defined types. E.g., SYS.SYSALIASES.ALIASINFO.
• ANSI - As part of the work on DERBY-651, we added ANSI UDTs. These are user defined types which are declared via the CREATE TYPE statement. These have schema-qualified names. The CREATE TYPE statement basically binds a schema-qualified name to the name of a Java class.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected String	className	This class implements Formatable.

Fields inherited from class BaseTypeIdImpl

JDBCTypeId, schemaName, unqualifiedName

Constructor Summary

Constructors

Constructor	Description
UserDefinedTypeIdImpl()	Public niladic constructor.
UserDefinedTypeIdImpl(String className)	Constructor for a UserDefinedTypeIdImpl.
UserDefinedTypeIdImpl(String schemaName, String unqualifiedName, String className)	Constructor for a UDT.

Method Summary

Modifier and Type	Method	Description
String	getClassName()	Return the java class name for this type
int	getTypeFormatId()	Get the formatID which corresponds to this class.
boolean	isBound()	Has this user type been bound?
void	readExternal(ObjectInput in)	Read this object from a stream of stored objects.
boolean	userType()	Does this type id represent a user type?
void	writeExternal(ObjectOutput out)	Write this object to a stream of stored objects.

Methods inherited from class BaseTypeIdImpl

equals, getJDBCTypeId, getSchemaName, getSQLTypeName, getUnqualifiedName, hashCode, isAnsiUDT, toParsableString, toString

Methods inherited from class Object

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

Field Details

className

protected String className

This class implements Formatable. That means that it can write itself to and from a formatted stream. If you add more fields to this class, make sure that you also write/read them with the writeExternal()/readExternal() methods. If, inbetween releases, you add more fields to this class, then you should bump the version number emitted by the getTypeFormatId() method.

Constructor Details

UserDefinedTypeIdImpl

public UserDefinedTypeIdImpl()

Public niladic constructor. Needed for Formatable interface to work.

UserDefinedTypeIdImpl

public UserDefinedTypeIdImpl(String className)
                      throws StandardException

Constructor for a UserDefinedTypeIdImpl. The SQLTypeName of a UserDefinedType is assumed to be its className for Derby-only UserDefinedTypes. For actual user created UDTs, the SQLTypeName is a schema qualified name.

Parameters:

className - The SQL name of the type

Throws:

StandardException

UserDefinedTypeIdImpl

public UserDefinedTypeIdImpl(String schemaName,
 String unqualifiedName,
 String className)

Constructor for a UDT.

Parameters:

schemaName - Schema that the UDT lives in.

unqualifiedName - The name of the type inside that schema.

className - The Java class bound to the SQL type.

Method Details

getClassName

public String getClassName()

Return the java class name for this type

userType

public boolean userType()

Does this type id represent a user type?

Overrides:

userType in class BaseTypeIdImpl

isBound

public boolean isBound()

Has this user type been bound?

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
ClassNotFoundException

Read this object from a stream of stored objects.

Specified by:

readExternal in interface Externalizable

Overrides:

readExternal in class BaseTypeIdImpl

Parameters:

in - read this.

Throws:

IOException - thrown on error

ClassNotFoundException - thrown on error

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Write this object to a stream of stored objects.

Specified by:

writeExternal in interface Externalizable

Overrides:

writeExternal in class BaseTypeIdImpl

Parameters:

out - write bytes here.

Throws:

IOException - thrown on error

getTypeFormatId

public int getTypeFormatId()

Get the formatID which corresponds to this class.

Specified by:

getTypeFormatId in interface TypedFormat

Overrides:

getTypeFormatId in class BaseTypeIdImpl

Returns:

the formatID of this class