org.sape.carbon.services.config.classloader
Class ClassloaderConfigurationDocument

java.lang.Object
  |
  +--org.sape.carbon.core.config.node.AbstractNode
        |
        +--org.sape.carbon.core.config.node.AbstractConfigurationDocument
              |
              +--org.sape.carbon.services.config.classloader.ClassloaderConfigurationDocument

All Implemented Interfaces:

ConfigurationDocument, Node

public class ClassloaderConfigurationDocument

extends AbstractConfigurationDocument

Implementation of ConfigurationDocument using streams found from a classloader.

Copyright 2003 Sapient

Since:

carbon 2.0

Version:

$Revision: 1.7 $($Author: dvoet $ / $Date: 2003/12/11 18:43:31 $)

Author:

Greg Hinkle, April 2003

Field Summary

private ConfigurationSource	configSource The source for configuration data.
private boolean	isInMemoryOnly Keeps track of whether or not this node was created in memory only or it is actually on the backing data store.
private org.apache.commons.logging.Log	log Provides a handle to Apache-commons logger
private String	resourcePath The path of the resource that contains this configuration.

Fields inherited from class org.sape.carbon.core.config.node.AbstractConfigurationDocument

configuration

Fields inherited from class org.sape.carbon.core.config.node.AbstractNode

childNodes, nodeListeners

Fields inherited from interface org.sape.carbon.core.config.node.Node

DELIMITER

Constructor Summary

ClassloaderConfigurationDocument(Node parent, String name, ConfigurationFormatService formatter, String resourcePath, ConfigurationSource configSource)
Constructor for ClassloaderConfigurationDocument.

Method Summary

protected boolean	backingDataExists() If this node exists, then it was either loaded from a classloader resource or it is in-memory-only.
protected void	closeOutputStream(OutputStream out) This implementation cannot write configurations to a backing data store.
protected void	destroyBackingData() This is only called in the case of in-memory-only configurations.
protected InputStream	openInputStream() This implementation opens an input stream of the resource itentified by this.resourcePath by calling classloader.getResourceAsStream(this.resourcePath)
protected OutputStream	openOutputStream() This implementation cannot write configurations to a backing data store.
void	refresh() This implementation only refreshes the node if it is not in memory only
int	remove() Only configurations that exist in-memory-only can be removed.
void	writeConfiguration(Configuration config) This implementation does not write through to the backing datastore as Classloader resources are read-only.

Methods inherited from class org.sape.carbon.core.config.node.AbstractConfigurationDocument

addNestedConfigurationDocument, closeInputStream, getAllChildNames, getFormatService, getNestedNodeFactory, issueNodeModifiedEvent, loadChild, notifyNestedDocuments, readConfiguration, writeChildReferences

Methods inherited from class org.sape.carbon.core.config.node.AbstractNode

addNodeListener, addNodeListener, addNodeListener, containsChild, fetchChild, fetchChildren, getAbsoluteName, getAddOrLoadChildLock, getAllowsChildren, getName, getParent, getReadOrAlterNodeLock, isRemoved, issueChildLoadedEvent, issueNodeRemovedEvent, removeRemovedChildren, setRemoved, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.sape.carbon.core.config.node.Node

addNodeListener, addNodeListener, containsChild, fetchChild, fetchChildren, getAbsoluteName, getAllowsChildren, getName, getParent, isRemoved

Field Detail

log

private org.apache.commons.logging.Log log

Provides a handle to Apache-commons logger

resourcePath

private final String resourcePath

The path of the resource that contains this configuration. final as this should never change during the life of the instance, if it does, more synchronization may be required.

configSource

private final ConfigurationSource configSource

The source for configuration data. final as this should never change during the life of the instance, if it does, more synchronization may be required.

isInMemoryOnly

private final boolean isInMemoryOnly

Keeps track of whether or not this node was created in memory only or it is actually on the backing data store. final as this should never change during the life of the instance, if it does, more synchronization may be required.

Constructor Detail

ClassloaderConfigurationDocument

public ClassloaderConfigurationDocument(Node parent,
                                        String name,
                                        ConfigurationFormatService formatter,
                                        String resourcePath,
                                        ConfigurationSource configSource)

Constructor for ClassloaderConfigurationDocument.

Parameters:

parent -

name -

formatter -

resourcePath -

Method Detail

writeConfiguration

public void writeConfiguration(Configuration config)

This implementation does not write through to the backing datastore as Classloader resources are read-only. The in-memory copy of the configuration is replaced with a clone of the config parameter

This method is synchronized internally to prevent multiple writes from saving Configurations concurrently and to make sure that no one is writing a new Configuration while someone else is reading.

Specified by:

writeConfiguration in interface ConfigurationDocument

Overrides:

writeConfiguration in class AbstractConfigurationDocument

Parameters:

config - the new Configuration

openInputStream

protected InputStream openInputStream()
                               throws IOException

This implementation opens an input stream of the resource itentified by this.resourcePath by calling classloader.getResourceAsStream(this.resourcePath)

Specified by:

openInputStream in class AbstractConfigurationDocument

Returns:

InputStream the InputStream from which to read the Configuration object within this ConfigurationDocument

IOException

openOutputStream

protected OutputStream openOutputStream()
                                 throws IOException

This implementation cannot write configurations to a backing data store. writeConfiguration has been overridden in this class so as not to call this method.

Specified by:

openOutputStream in class AbstractConfigurationDocument

Returns:

OutputStream the OutputStream to which to write the Configuration object within this ConfigurationDocument

Throws:

UnsupportedOperationException

IOException

closeOutputStream

protected void closeOutputStream(OutputStream out)
                          throws IOException

This implementation cannot write configurations to a backing data store. writeConfiguration has been overridden in this class so as not to call this method.

Overrides:

closeOutputStream in class AbstractConfigurationDocument

Parameters:

out - the stream to close

Throws:

UnsupportedOperationException

IOException

destroyBackingData

protected void destroyBackingData()
                           throws NodeRemovalException

This is only called in the case of in-memory-only configurations. If this node is backed by a classloader resource, the remove method should throw an exception.

Specified by:

destroyBackingData in class AbstractNode

Throws:

NodeRemovalException - indicates an error removing the node

backingDataExists

protected boolean backingDataExists()

If this node exists, then it was either loaded from a classloader resource or it is in-memory-only. In either case the backing data exists so this method always returns true.

Specified by:

backingDataExists in class AbstractNode

Returns:

boolean true if the backing date exists, false otherwise

remove

public int remove()
           throws NodeRemovalException

Only configurations that exist in-memory-only can be removed.

Specified by:

remove in interface Node

Overrides:

remove in class AbstractConfigurationDocument

Throws:

NodeRemovalException - if this configuration was created from a classloader resource.

See Also:

synchronized to ensure no one is fetching or adding children while this method is removing them

refresh

public void refresh()

This implementation only refreshes the node if it is not in memory only

Specified by:

refresh in interface Node

Overrides:

refresh in class AbstractConfigurationDocument

See Also:

Node.refresh()