org.datanucleus.metadata

Class MetaDataUtils

java.lang.Object

org.datanucleus.metadata.MetaDataUtils

public class MetaDataUtils
extends Object

Utilities needed for the processing of MetaData.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MetaDataUtils() Protected constructor to prevent outside instantiation

Method Summary

Modifier and Type	Method and Description
boolean	arrayStorableAsByteArrayInSingleColumn(AbstractMemberMetaData fmd) Convenience method to determine if an array is storable in a single column as a byte array.
static boolean	getBooleanForString(String str, boolean dflt) Convenience method to return a boolean from the String value.
static FileMetaData[]	getFileMetaDataForInputFiles(MetaDataManager metaDataMgr, ClassLoaderResolver clr, String[] inputFiles) Method to take the provided input files and returns the FileMetaData that they implies.
String[]	getImplementationNamesForReferenceField(AbstractMemberMetaData fmd, FieldRole fieldRole, ClassLoaderResolver clr, MetaDataManager mmgr) 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
static List<AbstractClassMetaData>	getMetaDataForCandidates(Class cls, boolean subclasses, ExecutionContext ec) Convenience method to return the class metadata for the candidate and optionally its subclasses.
static PersistenceUnitMetaData	getMetaDataForPersistenceUnit(PluginManager pluginMgr, String persistenceFilename, String unitName, boolean validate, boolean namespaceAware, ClassLoaderResolver clr) Convenience method to parse the available persistence.xml file(s) and find the metadata for the specified persistence-unit.
static Class	getTypeOfDatastoreIdentity(IdentityMetaData idmd)
static String	getValueForExtensionRecursively(MetaData metadata, String key) Searches the meta data tree upwards starting with the given leaf, stops as soon as it finds an extension with the given key.
String[]	getValuesForCommaSeparatedAttribute(String attr) Convenience method that splits a comma-separated list of values into a String array (removing whitespace).
static String[]	getValuesForExtensionRecursively(MetaData metadata, String key) Searches the meta data tree upwards starting with the given leaf, stops as soon as it finds an extension with the given key.
static boolean	isJdbcTypeFloatingPoint(JdbcType jdbcType) Convenience method to return if a jdbc-type is floating point based.
static boolean	isJdbcTypeNumeric(JdbcType jdbcType) Convenience method to return if a jdbc-type is numeric.
static boolean	isJdbcTypeString(JdbcType jdbcType) Convenience method to return if a jdbc-type is character based.
static boolean	isMemberEmbedded(AbstractMemberMetaData mmd, RelationType relationType, ClassLoaderResolver clr, MetaDataManager mmgr) Convenience method to return whether a member is stored as embedded.
boolean	isMemberEmbedded(MetaDataManager mmgr, ClassLoaderResolver clr, AbstractMemberMetaData mmd, RelationType relationType, AbstractMemberMetaData ownerMmd) Convenience method to return if the specified member is embedded.
static PersistenceFileMetaData[]	parsePersistenceFiles(PluginManager pluginMgr, String persistenceFilename, boolean validate, boolean namespaceAware, ClassLoaderResolver clr) Method to parse the available "persistence.xml" files returning the metadata for all found.
static boolean	persistColumnAsNumeric(ColumnMetaData colmd) Convenience method for whether to persist the provided column as numeric.
static boolean	persistColumnAsString(ColumnMetaData colmd) Convenience method for whether to persist the provided column as string-based.
boolean	storesFCO(AbstractMemberMetaData fmd, ExecutionContext ec) Convenience method that returns if a field stores a First-Class object (FCO).
boolean	storesPersistable(AbstractMemberMetaData fmd, ExecutionContext ec) 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

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,
                                 ExecutionContext ec)

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

ec - ExecutionContext

Returns:

Whether it stores a persistable object

storesFCO

public boolean storesFCO(AbstractMemberMetaData fmd,
                         ExecutionContext ec)

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

ec - ExecutionContext

Returns:

Whether it stores a FCO

getValuesForCommaSeparatedAttribute

public String[] getValuesForCommaSeparatedAttribute(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 String[] getImplementationNamesForReferenceField(AbstractMemberMetaData fmd,
                                                        FieldRole fieldRole,
                                                        ClassLoaderResolver clr,
                                                        MetaDataManager mmgr)

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

mmgr - MetaData manager

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

getBooleanForString

public static boolean getBooleanForString(String str,
                                          boolean dflt)

Convenience method to return a boolean from the String value. If the string is null then dflt is returned.

Parameters:

str - The string (should be "true", "false")

dflt - The default

Returns:

The boolean to use

getValueForExtensionRecursively

public static String getValueForExtensionRecursively(MetaData metadata,
                                                     String key)

Searches the meta data tree upwards starting with the given leaf, stops as soon as it finds an extension with the given key.

Parameters:

metadata - Leaf of the meta data tree, where the search should start

key - The key of the extension

Returns:

The value of the extension (null if not existing)

getValuesForExtensionRecursively

public static String[] getValuesForExtensionRecursively(MetaData metadata,
                                                        String key)

Searches the meta data tree upwards starting with the given leaf, stops as soon as it finds an extension with the given key.

Parameters:

metadata - Leaf of the meta data tree, where the search should start

key - The key of the extension

Returns:

The values of the extension (null if not existing)

isJdbcTypeNumeric

public static boolean isJdbcTypeNumeric(JdbcType jdbcType)

Convenience method to return if a jdbc-type is numeric.

Parameters:

jdbcType - The type string

Returns:

Whether it is numeric

isJdbcTypeFloatingPoint

public static boolean isJdbcTypeFloatingPoint(JdbcType jdbcType)

Convenience method to return if a jdbc-type is floating point based.

Parameters:

jdbcType - The type string

Returns:

Whether it is floating point ased

isJdbcTypeString

public static boolean isJdbcTypeString(JdbcType jdbcType)

Convenience method to return if a jdbc-type is character based.

Parameters:

jdbcType - The type string

Returns:

Whether it is character based

getMetaDataForCandidates

public static List<AbstractClassMetaData> getMetaDataForCandidates(Class cls,
                                                                   boolean subclasses,
                                                                   ExecutionContext ec)

Convenience method to return the class metadata for the candidate and optionally its subclasses. Caters for the class being a persistent interface.

Parameters:

cls - The class

subclasses - Include subclasses?

ec - ExecutionContext

Returns:

The metadata, starting with the candidate

Throws:

NucleusUserException - if candidate is an interface with no metadata (i.e not persistent)

getFileMetaDataForInputFiles

public static FileMetaData[] getFileMetaDataForInputFiles(MetaDataManager metaDataMgr,
                                                          ClassLoaderResolver clr,
                                                          String[] inputFiles)

Method to take the provided input files and returns the FileMetaData that they implies. Loads the files into the provided MetaDataManager in the process.

Parameters:

metaDataMgr - Manager for MetaData

clr - ClassLoader resolver

inputFiles - Input metadata/class files

Returns:

The FileMetaData for the input

Throws:

NucleusException - Thrown if error(s) occur in processing the input

parsePersistenceFiles

public static PersistenceFileMetaData[] parsePersistenceFiles(PluginManager pluginMgr,
                                                              String persistenceFilename,
                                                              boolean validate,
                                                              boolean namespaceAware,
                                                              ClassLoaderResolver clr)

Method to parse the available "persistence.xml" files returning the metadata for all found. Searches for all files "META-INF/persistence.xml" in the CLASSPATH of the current thread.

Parameters:

pluginMgr - PluginManager

persistenceFilename - Name of persistence file (if null will use "persistence.xml")

validate - Whether to validate the persistence file

namespaceAware - Whether to support namespaces

clr - ClassLoader resolver

Returns:

The metadata for all "persistence.xml" files

getMetaDataForPersistenceUnit

public static PersistenceUnitMetaData getMetaDataForPersistenceUnit(PluginManager pluginMgr,
                                                                    String persistenceFilename,
                                                                    String unitName,
                                                                    boolean validate,
                                                                    boolean namespaceAware,
                                                                    ClassLoaderResolver clr)

Convenience method to parse the available persistence.xml file(s) and find the metadata for the specified persistence-unit.

Parameters:

pluginMgr - Plugin Manager

persistenceFilename - Filename of the persistence.xml (or null if using default "META-INF/persistence.xml")

unitName - Name of the persistence unit

validate - Whether to validate the XML

namespaceAware - Whether the XML is namespace aware

clr - ClassLoader resolver

Returns:

Metadata for the persistence-unit (if found), or null (if not found)

persistColumnAsNumeric

public static boolean persistColumnAsNumeric(ColumnMetaData colmd)

Convenience method for whether to persist the provided column as numeric. Returns true if it has the jdbcType defined as "int"/"integer"

Parameters:

colmd - Metadata for the column

Returns:

Whether explicitly specified to use numeric, otherwise returns false.

persistColumnAsString

public static boolean persistColumnAsString(ColumnMetaData colmd)

Convenience method for whether to persist the provided column as string-based. Returns true if it has the jdbcType defined as "varchar"/"char"

Parameters:

colmd - Metadata for the column

Returns:

Whether explicitly specified to use String, otherwise returns false.

getTypeOfDatastoreIdentity

public static Class getTypeOfDatastoreIdentity(IdentityMetaData idmd)

isMemberEmbedded

public static boolean isMemberEmbedded(AbstractMemberMetaData mmd,
                                       RelationType relationType,
                                       ClassLoaderResolver clr,
                                       MetaDataManager mmgr)

Convenience method to return whether a member is stored as embedded. This caters for not just "mmd.isEmbedded" returning true, but also the "embeddedOnly" of the related type, as well as whether there is <embedded> metadata for this member

Parameters:

mmd - Metadata for the member

relationType - The relation type for this member

clr - ClassLoader resolver

mmgr - MetaData manager

Returns:

Whether it is embedded

isMemberEmbedded

public boolean isMemberEmbedded(MetaDataManager mmgr,
                                ClassLoaderResolver clr,
                                AbstractMemberMetaData mmd,
                                RelationType relationType,
                                AbstractMemberMetaData ownerMmd)

Convenience method to return if the specified member is embedded. Only applies to relation fields, since all other fields are always "embedded". TODO Likely ought to change last arg to List<AbstractMemberMetaData> for multilevel of embedded

Parameters:

mmgr - Metadata manager

clr - ClassLoader resolver

mmd - Metadata for the member we are interested in

relationType - Relation type of the member we are interested in

ownerMmd - Optional metadata for the owner member (for nested embeddeds only. Set to null if not relevant to the member in question).

Returns:

Whether the member is embedded