org.exolab.castor.mapping

Class Mapping


public class Mapping
extends java.lang.Object

Utility class for loading mapping files and providing them to the XML marshaller, JDO engine etc. The mapping file can be loaded from a URL, input stream or SAX InputSource.

Multiple mapping files can be loaded with the same Mapping object. When loading master mapping files that include other mapping files it might be convenient to use setBaseURL(String) or setEntityResolver(EntityResolver).

If the desired class loader is different than the one used by Castor (e.g. if Castor is installed as a Java extension), the Mapping object can be constructed with the proper class loader.

The following example loads two mapping files:

 Mapping mapping;

 mapping = new Mapping( getClass().getClassLoader() );
 mapping.loadMapping( "mapping.xml" );
 mapping.loadMapping( url );
 
Version:
$Revision: 1.1.1.1 $ $Date: 2003/03/03 07:08:27 $
Author:
Assaf Arkin

Nested Class Summary

(package private) class
Mapping.ClassMappingResolver
An IDResolver to allow us to resolve ClassMappings from included Mapping files
(package private) static class
Mapping.EngineMapping
Associates engine name (XML, JDO, etc) with the class of its mapping loader.
(package private) class
Mapping.MappingState
A class to keep track of the loaded mapping.

Field Summary

static Mapping.EngineMapping
DAX
Use this object to obtain the mapping resolver for DAX from getResolver.
static Mapping.EngineMapping
JDO
Use this object to obtain the mapping resolver for JDO from getResolver.
static Mapping.EngineMapping
XML
Use this object to obtain the mapping resolver for XML from getResolver.

Constructor Summary

Mapping()
Constructs a new mapping.
Mapping(ClassLoader loader)
Constructs a new mapping.

Method Summary

ClassLoader
getClassLoader()
Returns the class loader used by this mapping object.
MappingResolver
getResolver(Mapping.EngineMapping engine)
Returns a mapping resolver for the suitable engine.
MappingResolver
getResolver(Mapping.EngineMapping engine, Object param)
Returns a mapping resolver for the suitable engine.
MappingRoot
getRoot()
Returns a MappingRoot which contains all loaded mapping classes and key generators definition.
void
loadMapping(InputSource source)
Loads the mapping from the specified input source.
void
loadMapping(String url)
Loads the mapping from the specified URL.
void
loadMapping(URL url)
Loads the mapping from the specified URL.
void
setAllowRedefinitions(boolean allow)
Enables or disables the ability to allow the redefinition of class mappings.
void
setBaseURL(String url)
Sets the base URL for the mapping and related files.
void
setEntityResolver(EntityResolver resolver)
Sets the entity resolver.
void
setLogWriter(PrintWriter logWriter)
Sets the log writer.

Field Details

DAX

public static final Mapping.EngineMapping DAX
Use this object to obtain the mapping resolver for DAX from getResolver.

JDO

public static final Mapping.EngineMapping JDO
Use this object to obtain the mapping resolver for JDO from getResolver.

XML

public static final Mapping.EngineMapping XML
Use this object to obtain the mapping resolver for XML from getResolver.

Constructor Details

Mapping

public Mapping()
Constructs a new mapping.

Mapping

public Mapping(ClassLoader loader)
Constructs a new mapping.
Parameters:
loader - The class loader to use, null for the default

Method Details

getClassLoader

public ClassLoader getClassLoader()
Returns the class loader used by this mapping object. The returned class loaded may be the one passed in the constructor, the one used to load Castor, or in some 1.1 JVMs null.
Returns:
The class loader used by this mapping object (may be null)

getResolver

public MappingResolver getResolver(Mapping.EngineMapping engine)
            throws MappingException
Returns a mapping resolver for the suitable engine. The engine's specific mapping loader is created and used to create engine specific descriptors, returning a suitable mapping resolver. The mapping resolver is cached in memory and returned in subsequent method calls.
Parameters:
engine - The mapping engine
Returns:
A mapping resolver
Throws:
MappingException - A mapping error occured preventing descriptors from being generated from the loaded mapping
See Also:
JDO, XML, DAX

getResolver

public MappingResolver getResolver(Mapping.EngineMapping engine,
                                   Object param)
            throws MappingException
Returns a mapping resolver for the suitable engine. The engine's specific mapping loader is created and used to create engine specific descriptors, returning a suitable mapping resolver. The mapping resolver is cached in memory and returned in subsequent method calls.
Parameters:
engine - The mapping engine
param - Arbitrary parameter that is to be passed to resolver.loadMapping()
Returns:
A mapping resolver
Throws:
MappingException - A mapping error occured preventing descriptors from being generated from the loaded mapping
See Also:
JDO, XML, DAX

getRoot

public MappingRoot getRoot()
Returns a MappingRoot which contains all loaded mapping classes and key generators definition.

loadMapping

public void loadMapping(InputSource source)
            throws IOException,
                   MappingException
Loads the mapping from the specified input source.
Parameters:
source - The input source
Throws:
MappingException - The mapping file is invalid

loadMapping

public void loadMapping(String url)
            throws IOException,
                   MappingException
Loads the mapping from the specified URL. If an entity resolver was specified, will use the entity resolver to resolve the URL. This method is also used to load mappings referenced from another mapping or configuration file.
Parameters:
url - The URL of the mapping file
Throws:
MappingException - The mapping file is invalid

loadMapping

public void loadMapping(URL url)
            throws IOException,
                   MappingException
Loads the mapping from the specified URL.
Parameters:
url - The URL of the mapping file
Throws:
MappingException - The mapping file is invalid

setAllowRedefinitions

public void setAllowRedefinitions(boolean allow)
Enables or disables the ability to allow the redefinition of class mappings.
Parameters:
allow - a boolean that when true enables redefinitions.

setBaseURL

public void setBaseURL(String url)
Sets the base URL for the mapping and related files. If the base URL is known, files can be included using relative names. Any URL can be passed, if the URL can serve as a base URL it will be used. If url is an absolute path, it is converted to a file URL.
Parameters:
url - The base URL

setEntityResolver

public void setEntityResolver(EntityResolver resolver)
Sets the entity resolver. The entity resolver can be used to resolve external entities and cached documents that are used from within mapping files.
Parameters:
resolver - The entity resolver to use

setLogWriter

public void setLogWriter(PrintWriter logWriter)
Sets the log writer. If not null, errors and other messages will be directed to that log writer.
Parameters:
logWriter - The log writer to use

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