org.datanucleus.metadata
Class MetaDataUtils

java.lang.Object
  org.datanucleus.metadata.MetaDataUtils

public class MetaDataUtils
extends java.lang.Object

Utilities needed for the processing of MetaData.

Version:

$Revision: 1.49 $

Field Summary

protected static Localiser

LOCALISER

Constructor Summary

protected

MetaDataUtils() Protected constructor to prevent outside instantiation

Method Summary

boolean	arrayStorableAsByteArrayInSingleColumn(AbstractMemberMetaData fmd) Convenience method to determine if an array is storable in a single column as a byte array.
java.lang.String[]	getImplementationNamesForReferenceField(AbstractMemberMetaData fmd, int fieldRole, ClassLoaderResolver clr) Convenience method to return the class names of the available implementation types for an interface/Object field, given its required role.
static MetaDataUtils	getInstance() Gets an instance of MetaDataUtils
java.lang.String[]	getValuesForCommaSeparatedAttribute(java.lang.String attr) Convenience method that splits a comma-separated list of values into a String array (removing whitespace).
boolean	storesFCO(AbstractMemberMetaData fmd, ClassLoaderResolver clr) Convenience method that returns if a field stores a First-Class object (FCO).
boolean	storesPersistable(AbstractMemberMetaData fmd, ClassLoaderResolver clr) Convenience method that returns if a field stores a persistable object.

Methods inherited from class java.lang.Object

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

Field Detail

LOCALISER

protected static final Localiser LOCALISER

Constructor Detail

MetaDataUtils

protected MetaDataUtils()

Protected constructor to prevent outside instantiation

Method Detail

getInstance

public static MetaDataUtils getInstance()

Gets an instance of MetaDataUtils

Returns:

a singleton instance of MetaDataUtils

arrayStorableAsByteArrayInSingleColumn

public boolean arrayStorableAsByteArrayInSingleColumn(AbstractMemberMetaData fmd)

Convenience method to determine if an array is storable in a single column as a byte array.

Parameters:

fmd - The field

Returns:

Whether this is an array that can be stored in a single column as non-serialised

storesPersistable

public boolean storesPersistable(AbstractMemberMetaData fmd,
                                 ClassLoaderResolver clr)

Convenience method that returns if a field stores a persistable object. Doesn't care if the persistable object is serialised or embedded, just that it is persistable.

Parameters:

fmd - MetaData for the field

clr - ClassLoaderResolver resolver

Returns:

Whether it stores a persistable object

storesFCO

public boolean storesFCO(AbstractMemberMetaData fmd,
                         ClassLoaderResolver clr)

Convenience method that returns if a field stores a First-Class object (FCO). If a field object is serialised/embedded then doesn't count the object as FCO - use storesPersistable() if you want that not checking.

Parameters:

fmd - MetaData for the field

clr - ClassLoaderResolver resolver

Returns:

Whether it stores a FCO

getValuesForCommaSeparatedAttribute

public java.lang.String[] getValuesForCommaSeparatedAttribute(java.lang.String attr)

Convenience method that splits a comma-separated list of values into a String array (removing whitespace).

Parameters:

attr - The attribute value

Returns:

The string components

getImplementationNamesForReferenceField

public java.lang.String[] getImplementationNamesForReferenceField(AbstractMemberMetaData fmd,
                                                                  int fieldRole,
                                                                  ClassLoaderResolver clr)

Convenience method to return the class names of the available implementation types for an interface/Object field, given its required role. Removes all duplicates from the list.

Parameters:

fmd - MetaData for the field

fieldRole - The role of the field

clr - the ClassLoaderResolver

Returns:

Names of the classes of the possible implementations of this interface/Object

Throws:

NucleusUserException - if no implementation types are found for the reference type field