org.apache.muse.core
Class AbstractFilePersistence

java.lang.Object
  extended by org.apache.muse.core.AbstractFilePersistence
All Implemented Interfaces:
InitializationParameters, Persistence
Direct Known Subclasses:
NotificationProducerFilePersistence, RouterFilePersistence, ServiceGroupFilePersistence

public abstract class AbstractFilePersistence
extends Object
implements Persistence

AbstractFilePersistence is an abstract component that provides generic resource-state-to-file utilities without specifying the format of the XML that goes into the files. It can be used by resources or capabilities that wish to save state to disk and reload that state the next time the application is initialized.

Author:
Dan Jemiolo (danj)

Constructor Summary
AbstractFilePersistence()
           
 
Method Summary
protected  void createResourceFile(EndpointReference epr, Resource resource)
          Creates the proper file name for the given resource instance and then delegates creation of the file's contents to the abstract method of the same name.
protected abstract  void createResourceFile(EndpointReference epr, Resource resource, File resourceFile)
          This method should be overridden by concrete file-based persistence classes to create the given file and fill it with the appropriate XML content.
protected  void destroyResourceFile(EndpointReference epr)
          Finds the file associated with the given resource EPR and removes it from the file system.
protected  String getContextPath(EndpointReference epr)
           
protected  Integer getFileNumber(String fileName)
           
protected  Map getFileNumberTables()
           
protected abstract  String getFilePrefix()
           
 String getInitializationParameter(String name)
           
 Map getInitializationParameters()
           
protected  String getNextFileName(int fileNumber)
           
protected  int getNextFileNumber(String contextPath)
           
protected  File getPersistenceDirectory()
           
 String getPersistenceLocation()
           
 ResourceManager getResourceManager()
           
protected  File getResourceTypeDirectory(String contextPath)
           
 void reload()
          This implementation re-loads all saved instances of the resource types found in the ResourceManager.
protected abstract  Resource reloadResource(String contextPath, Element resourceXML)
          This method should be overridden by concrete file-based persistence classes to update a resource instance with the saved data from the XML fragment.
protected  void reloadResources(String contextPath, File resourceTypeDir)
          This method finds all of the files in the resource type's persistence directory and reloads them one at a time.
 void setInitializationParameters(Map parameters)
          Allows the resource's creator to provide it with arbitrary name-value pairs that may be used during initialization.
 void setPersistenceLocation(String location)
           
 void setResourceManager(ResourceManager manager)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

AbstractFilePersistence

public AbstractFilePersistence()
Method Detail

createResourceFile

protected void createResourceFile(EndpointReference epr,
                                  Resource resource)
                           throws SoapFault
Creates the proper file name for the given resource instance and then delegates creation of the file's contents to the abstract method of the same name.

Parameters:
epr -
resource -
Throws:
SoapFault
See Also:
getNextFileNumber(String), createResourceFile(EndpointReference, Resource, File)

createResourceFile

protected abstract void createResourceFile(EndpointReference epr,
                                           Resource resource,
                                           File resourceFile)
                                    throws SoapFault
This method should be overridden by concrete file-based persistence classes to create the given file and fill it with the appropriate XML content. Classes that are only interested in the serialization of a certain capability's data can use the Resource object to get access to said capability.

Parameters:
epr - The EPR that maps to the given Resource in the ResourceManager.
resource - The resource instance whose state is being persisted.
resourceFile - The File object that represents the yet-to-be-created XML file that will contain the content generated by this method. The implementation of this method must be sure to create the File on disk somehow.
Throws:
SoapFault -
  • If there is an error generating the proper content for the persistence file.
  • If there is an I/O error while reading or writing to the file system.

destroyResourceFile

protected void destroyResourceFile(EndpointReference epr)
                            throws SoapFault
Finds the file associated with the given resource EPR and removes it from the file system. This method should be called when a resource is destroyed (gone forever), but not when it is merely shutdown (because of server reboot, etc.).

Parameters:
epr - The EPR of the resource that has been permanently destroyed.
Throws:
SoapFault

getContextPath

protected String getContextPath(EndpointReference epr)
Parameters:
epr -
Returns:
The last token after the last slash in the EPR's address. That is, for an EPR with address http://example.com/my-resource, the method returns 'my-resource'.

getFileNumber

protected Integer getFileNumber(String fileName)
Parameters:
fileName -
Returns:
The number at the end of the file name, before the suffix. That is, for a file named 'my-file-14.xml', the method returns 14.

getFileNumberTables

protected Map getFileNumberTables()

getFilePrefix

protected abstract String getFilePrefix()
Returns:
The common string that will start all files created by the persistence implementation. This string will have the next file number appended to it in order to create unique file names.
See Also:
getNextFileNumber(String)

getInitializationParameter

public String getInitializationParameter(String name)
Specified by:
getInitializationParameter in interface InitializationParameters
Returns:
The value of the initialization parameter, or null if it does not exist.

getInitializationParameters

public Map getInitializationParameters()
Specified by:
getInitializationParameters in interface InitializationParameters
Returns:
The set of name-value pairs provided at initialization time. The Map may be empty.

getNextFileName

protected String getNextFileName(int fileNumber)
Parameters:
fileNumber -
Returns:
A string of the following format: {file-prefix}{file-number}.xml

getNextFileNumber

protected int getNextFileNumber(String contextPath)
Returns:
The next number that is available for creation of unique file names; this number is determined by taking the largest number currently used and incrementing it by one. The method does not attempt to reuse numbers in 'gaps' caused by deletions (that is, if numbers 1, 2, 5, and 6 are used, the method returns 7, not 3).

getPersistenceDirectory

protected File getPersistenceDirectory()
Returns:
The File directory that was specified as the persistence location in muse.xml. The directory may not exist, so use File.exists() and/or File.mkdirs() to prevent I/O errors.

getPersistenceLocation

public String getPersistenceLocation()
Specified by:
getPersistenceLocation in interface Persistence
Returns:
The value specified in muse.xml under the persistence element. The semantics of this value are dependent on the type of storage used by the implementation class. As an example, a simple file-based persistence class might interpret the location to be the directory where files are stored; a database-oriented class might interpret it as the JNDI URI for the database.

getResourceManager

public ResourceManager getResourceManager()
Specified by:
getResourceManager in interface Persistence
Returns:
The ResourceManager that stores all of the resource type definitions and all current resource instances.

getResourceTypeDirectory

protected File getResourceTypeDirectory(String contextPath)
Parameters:
contextPath -
Returns:
Returns a directory for a given resource type, under the specified persistence location. The name of the directory is the context path provided. If the directory does not exist, this method will create it before returning the File object.
See Also:
getPersistenceDirectory(), File.mkdirs()

reload

public void reload()
            throws SoapFault
This implementation re-loads all saved instances of the resource types found in the ResourceManager. It delegates the actual reloading work to reloadResources(String, File).

Specified by:
reload in interface Persistence
Throws:
SoapFault
See Also:
reloadResources(String, File)

reloadResource

protected abstract Resource reloadResource(String contextPath,
                                           Element resourceXML)
                                    throws SoapFault
This method should be overridden by concrete file-based persistence classes to update a resource instance with the saved data from the XML fragment. The resource instance may be created by this method, or it may exist prior to invocation.

Parameters:
contextPath - The context path of the instance's resource type.
resourceXML - The persisted data that must be reloaded.
Returns:
The Resource instance whose state (or part of it) has been reloaded from XML. The Resource may have already existed prior to the method being called, and simply had one of its capabilities updated with saved data; it may also have been created by the method and initialized right before return.
Throws:
SoapFault

reloadResources

protected void reloadResources(String contextPath,
                               File resourceTypeDir)
                        throws SoapFault
This method finds all of the files in the resource type's persistence directory and reloads them one at a time. It delegates the reloading of individual resource instances to reloadResource(String, Element).

Parameters:
contextPath -
resourceTypeDir -
Throws:
SoapFault
See Also:
reloadResource(String, Element)

setInitializationParameters

public void setInitializationParameters(Map parameters)
Description copied from interface: InitializationParameters
Allows the resource's creator to provide it with arbitrary name-value pairs that may be used during initialization. The way that these values are used and/or stored is an implementation detail, and there is no requirement that this feature be used - it is a generic way to specify deployment/initialization parameters. This method should be called before the resource is initialized.

Specified by:
setInitializationParameters in interface InitializationParameters
Parameters:
parameters - A simple set of name-value pairs - Map[String, String] - that contains initialization parameters for the resource.

setPersistenceLocation

public void setPersistenceLocation(String location)
Specified by:
setPersistenceLocation in interface Persistence

setResourceManager

public void setResourceManager(ResourceManager manager)
Specified by:
setResourceManager in interface Persistence


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