org.apache.commons.configuration
Class XMLConfiguration

java.lang.Object
  org.apache.commons.configuration.AbstractConfiguration
      org.apache.commons.configuration.HierarchicalConfiguration
          org.apache.commons.configuration.XMLConfiguration

All Implemented Interfaces:

Configuration, FileConfiguration

Direct Known Subclasses:

HierarchicalXMLConfiguration

public class XMLConfiguration

extends HierarchicalConfiguration

implements FileConfiguration

A specialized hierarchical configuration class that is able to parse XML documents.

The parsed document will be stored keeping its structure. The class also tries to preserve as much information from the loaded XML document as possible, including comments and processing instructions. These will be contained in documents created by the save() methods, too.

Since:

commons-configuration 1.0

Version:

$Revision$, $Date: 2005-03-05 11:26:22 +0100 (Sat, 05 Mar 2005) $

Author:

Jörg Schaible, Oliver Heger

Nested Class Summary

Nested classes inherited from class org.apache.commons.configuration.HierarchicalConfiguration

HierarchicalConfiguration.BuilderVisitor, HierarchicalConfiguration.Node, HierarchicalConfiguration.NodeVisitor

Field Summary

Fields inherited from class org.apache.commons.configuration.AbstractConfiguration

END_TOKEN, START_TOKEN

Constructor Summary

XMLConfiguration()
Creates a new instance of XMLConfiguration.

XMLConfiguration(File file)
Creates a new instance of XMLConfiguration.

XMLConfiguration(String fileName)
Creates a new instance of XMLConfiguration.

XMLConfiguration(URL url)
Creates a new instance of XMLConfiguration.

Method Summary

protected void	addPropertyDirect(String key, Object obj) Adds the property with the specified key.
void	clearProperty(String key) Remove a property from the configuration.
void	clearTree(String key) Removes all values of the property with the given name and of keys that start with this name.
protected Document	createDocument() Creates a DOM document from the internal tree of configuration nodes.
protected HierarchicalConfiguration.Node	createNode(String name) Creates a new node object.
String	getBasePath() Return the base path.
Document	getDocument() Returns the XML document this configuration was loaded from.
String	getEncoding() Return the encoding used to store the configuration file.
File	getFile() Return the file where the configuration is stored.
String	getFileName() Return the name of the file.
ReloadingStrategy	getReloadingStrategy() Return the reloading strategy.
String	getRootElementName() Returns the name of the root element.
URL	getURL() Return the URL where the configuration is stored.
void	initProperties(Document document, boolean elemRefs) Initializes this configuration from an XML document.
boolean	isAutoSave() Tells if properties are automatically saved to the disk.
void	load() Load the configuration from the underlying URL.
void	load(File file) Load the configuration from the specified file.
void	load(InputStream in) Load the configuration from the specified stream, using the encoding returned by getEncoding().
void	load(InputStream in, String encoding) Load the configuration from the specified stream, using the specified encoding.
void	load(Reader in) Load the properties from the given reader.
void	load(String fileName) Locate the specified file and load the configuration.
void	load(URL url) Load the configuration from the specified URL.
void	reload() Reload the configuration.
void	save() Save the configuration.
void	save(File file) Save the configuration to the specified file.
void	save(OutputStream out) Save the configuration to the specified stream, using the encoding returned by getEncoding().
void	save(OutputStream out, String encoding) Save the configuration to the specified stream, using the specified encoding.
void	save(String fileName) Save the configuration to the specified file.
void	save(URL url) Save the configuration to the specified URL if it's a file URL.
void	save(Writer writer) Saves the configuration to the specified writer.
void	setAutoSave(boolean autoSave) Enable of disable the automatical saving of modified properties to the disk.
void	setBasePath(String basePath) Set the base path.
void	setEncoding(String encoding) Set the encoding used to store the configuration file.
void	setFile(File file) Set the file where the configuration is stored.
void	setFileName(String fileName) Set the name of the file.
void	setProperty(String key, Object value) Set a property, this will replace any previously set values.
void	setReloadingStrategy(ReloadingStrategy strategy) Set the reloading strategy.
void	setRootElementName(String name) Sets the name of the root element.
void	setURL(URL url) The URL where the configuration is stored.

Methods inherited from class org.apache.commons.configuration.HierarchicalConfiguration

addNodes, clearNode, containsKey, createAddPath, fetchAddNode, fetchNodeList, findLastPathNode, findPropertyNodes, getKeys, getKeys, getMaxIndex, getProperty, getRoot, isEmpty, nodeDefined, removeNode, setRoot, subset

Methods inherited from class org.apache.commons.configuration.AbstractConfiguration

addProperty, clear, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getDelimiter, getDouble, getDouble, getDouble, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getList, getList, getLong, getLong, getLong, getProperties, getProperties, getShort, getShort, getShort, getString, getString, getStringArray, interpolate, interpolateHelper, isThrowExceptionOnMissing, resolveContainerStore, setDelimiter, setThrowExceptionOnMissing

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.configuration.Configuration

addProperty, clear, containsKey, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getDouble, getDouble, getDouble, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getKeys, getKeys, getList, getList, getLong, getLong, getLong, getProperties, getProperty, getShort, getShort, getShort, getString, getString, getStringArray, isEmpty, subset

Constructor Detail

XMLConfiguration

public XMLConfiguration()

Creates a new instance of XMLConfiguration.

XMLConfiguration

public XMLConfiguration(String fileName)
                 throws ConfigurationException

Creates a new instance of XMLConfiguration. The configuration is loaded from the specified file

Parameters:

fileName - the name of the file to load

Throws:

ConfigurationException - if the file cannot be loaded

XMLConfiguration

public XMLConfiguration(File file)
                 throws ConfigurationException

Creates a new instance of XMLConfiguration. The configuration is loaded from the specified file.

Parameters:

file - the file

Throws:

ConfigurationException - if an error occurs while loading the file

XMLConfiguration

public XMLConfiguration(URL url)
                 throws ConfigurationException

Creates a new instance of XMLConfiguration. The configuration is loaded from the specified URL.

Parameters:

url - the URL

Throws:

ConfigurationException - if loading causes an error

Method Detail

getRootElementName

public String getRootElementName()

Returns the name of the root element. If this configuration was loaded from a XML document, the name of this document's root element is returned. Otherwise it is possible to set a name for the root element that will be used when this configuration is stored.

Returns:

the name of the root element

setRootElementName

public void setRootElementName(String name)

Sets the name of the root element. This name is used when this configuration object is stored in an XML file. Note that setting the name of the root element works only if this configuration has been newly created. If the configuration was loaded from an XML file, the name cannot be changed and an UnsupportedOperationException exception is thrown. Whether this configuration has been loaded from an XML document or not can be found out using the getDocument() method.

Parameters:

name - the name of the root element

getDocument

public Document getDocument()

Returns the XML document this configuration was loaded from. The return value is null if this configuration was not loaded from a XML document.

Returns:

the XML document this configuration was loaded from

addPropertyDirect

protected void addPropertyDirect(String key,
                                 Object obj)

Description copied from class: HierarchicalConfiguration

Adds the property with the specified key.

To be able to deal with the structure supported by this configuration implementation the passed in key is of importance, especially the indices it might contain. The following example should clearify this: Suppose the actual configuration contains the following elements:

 tables
    +-- table
            +-- name = user
            +-- fields
                    +-- field
                            +-- name = uid
                    +-- field
                            +-- name = firstName
                    ...
    +-- table
            +-- name = documents
            +-- fields
                   ...
 

In this example a database structure is defined, e.g. all fields of the first table could be accessed using the key tables.table(0).fields.field.name. If now properties are to be added, it must be exactly specified at which position in the hierarchy the new property is to be inserted. So to add a new field name to a table it is not enough to say just

 config.addProperty("tables.table.fields.field.name", "newField");
 

The statement given above contains some ambiguity. For instance it is not clear, to which table the new field should be added. If this method finds such an ambiguity, it is resolved by following the last valid path. Here this would be the last table. The same is true for the field; because there are multiple fields and no explicit index is provided, a new name property would be added to the last field - which is propably not what was desired.

To make things clear explicit indices should be provided whenever possible. In the example above the exact table could be specified by providing an index for the table element as in tables.table(1).fields. By specifying an index it can also be expressed that at a given position in the configuration tree a new branch should be added. In the example above we did not want to add an additional name element to the last field of the table, but we want a complete new field element. This can be achieved by specifying an invalid index (like -1) after the element where a new branch should be created. Given this our example would run:

 config.addProperty("tables.table(1).fields.field(-1).name", "newField");
 

With this notation it is possible to add new branches everywhere. We could for instance create a new table element by specifying

 config.addProperty("tables.table(-1).fields.field.name", "newField2");
 

(Note that because after the table element a new branch is created indices in following elements are not relevant; the branch is new so there cannot be any ambiguities.)

Overrides:

addPropertyDirect in class HierarchicalConfiguration

Parameters:

key - the key of the new property

obj - the value of the new property

clearProperty

public void clearProperty(String key)

Description copied from interface: Configuration

Remove a property from the configuration.

Specified by:

clearProperty in interface Configuration

Overrides:

clearProperty in class HierarchicalConfiguration

Parameters:

key - the key of the property to be removed

clearTree

public void clearTree(String key)

Description copied from class: HierarchicalConfiguration

Removes all values of the property with the given name and of keys that start with this name. So if there is a property with the key "foo" and a property with the key "foo.bar", a call of clearTree("foo") would remove both properties.

Overrides:

clearTree in class HierarchicalConfiguration

Parameters:

key - the key of the property to be removed

setProperty

public void setProperty(String key,
                        Object value)

Description copied from interface: Configuration

Set a property, this will replace any previously set values. Set values is implicitly a call to clearProperty(key), addProperty(key, value).

Specified by:

setProperty in interface Configuration

Overrides:

setProperty in class HierarchicalConfiguration

initProperties

public void initProperties(Document document,
                           boolean elemRefs)

Initializes this configuration from an XML document.

Parameters:

document - the document to be parsed

elemRefs - a flag whether references to the XML elements should be set

createDocument

protected Document createDocument()
                           throws ConfigurationException

Creates a DOM document from the internal tree of configuration nodes.

Returns:

the new document

Throws:

ConfigurationException - if an error occurs

createNode

protected HierarchicalConfiguration.Node createNode(String name)

Creates a new node object. This implementation returns an instance of the XMLNode class.

Overrides:

createNode in class HierarchicalConfiguration

Parameters:

name - the node's name

Returns:

the new node

load

public void load()
          throws ConfigurationException

Description copied from interface: FileConfiguration

Load the configuration from the underlying URL. If the URL is not specified, it attempts to locate the specified file name.

Specified by:

load in interface FileConfiguration

Throws:

ConfigurationException

load

public void load(String fileName)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Locate the specified file and load the configuration.

Specified by:

load in interface FileConfiguration

Parameters:

fileName - the name of the file loaded

Throws:

ConfigurationException

load

public void load(File file)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Load the configuration from the specified file.

Specified by:

load in interface FileConfiguration

Parameters:

file - the loaded file

Throws:

ConfigurationException

load

public void load(URL url)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Load the configuration from the specified URL.

Specified by:

load in interface FileConfiguration

Parameters:

url - the URL of the file loaded

Throws:

ConfigurationException

load

public void load(InputStream in)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Load the configuration from the specified stream, using the encoding returned by FileConfiguration.getEncoding().

Specified by:

load in interface FileConfiguration

Parameters:

in - the input stream

Throws:

ConfigurationException

load

public void load(InputStream in,
                 String encoding)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Load the configuration from the specified stream, using the specified encoding. If the encoding is null the default encoding is used.

Specified by:

load in interface FileConfiguration

Parameters:

in - the input stream

encoding - the encoding used. null to use the default encoding

Throws:

ConfigurationException

load

public void load(Reader in)
          throws ConfigurationException

Load the properties from the given reader. Note that the clear() method is not called, so the properties contained in the loaded file will be added to the actual set of properties.

Specified by:

load in interface FileConfiguration

Parameters:

in - An InputStream.

Throws:

ConfigurationException

save

public void save()
          throws ConfigurationException

Description copied from interface: FileConfiguration

Save the configuration.

Specified by:

save in interface FileConfiguration

Throws:

ConfigurationException

save

public void save(String fileName)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Save the configuration to the specified file.

Specified by:

save in interface FileConfiguration

Parameters:

fileName -

Throws:

ConfigurationException

save

public void save(File file)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Save the configuration to the specified file.

Specified by:

save in interface FileConfiguration

Parameters:

file -

Throws:

ConfigurationException

save

public void save(URL url)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Save the configuration to the specified URL if it's a file URL.

Specified by:

save in interface FileConfiguration

Parameters:

url -

Throws:

ConfigurationException

save

public void save(OutputStream out)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Save the configuration to the specified stream, using the encoding returned by FileConfiguration.getEncoding().

Specified by:

save in interface FileConfiguration

Parameters:

out -

Throws:

ConfigurationException

save

public void save(OutputStream out,
                 String encoding)
          throws ConfigurationException

Description copied from interface: FileConfiguration

Save the configuration to the specified stream, using the specified encoding. If the encoding is null the default encoding is used.

Specified by:

save in interface FileConfiguration

Parameters:

out -

encoding -

Throws:

ConfigurationException

save

public void save(Writer writer)
          throws ConfigurationException

Saves the configuration to the specified writer.

Specified by:

save in interface FileConfiguration

Parameters:

writer - the writer used to save the configuration

Throws:

ConfigurationException - if an error occurs

getFileName

public String getFileName()

Description copied from interface: FileConfiguration

Return the name of the file.

Specified by:

getFileName in interface FileConfiguration

setFileName

public void setFileName(String fileName)

Description copied from interface: FileConfiguration

Set the name of the file.

Specified by:

setFileName in interface FileConfiguration

Parameters:

fileName - the name of the file

getBasePath

public String getBasePath()

Description copied from interface: FileConfiguration

Return the base path.

Specified by:

getBasePath in interface FileConfiguration

setBasePath

public void setBasePath(String basePath)

Description copied from interface: FileConfiguration

Set the base path. Relative configurations are loaded from this path.

Specified by:

setBasePath in interface FileConfiguration

Parameters:

basePath - the base path.

getFile

public File getFile()

Description copied from interface: FileConfiguration

Return the file where the configuration is stored.

Specified by:

getFile in interface FileConfiguration

setFile

public void setFile(File file)

Description copied from interface: FileConfiguration

Set the file where the configuration is stored.

Specified by:

setFile in interface FileConfiguration

Parameters:

file -

getURL

public URL getURL()

Description copied from interface: FileConfiguration

Return the URL where the configuration is stored.

Specified by:

getURL in interface FileConfiguration

setURL

public void setURL(URL url)

Description copied from interface: FileConfiguration

The URL where the configuration is stored.

Specified by:

setURL in interface FileConfiguration

Parameters:

url -

setAutoSave

public void setAutoSave(boolean autoSave)

Description copied from interface: FileConfiguration

Enable of disable the automatical saving of modified properties to the disk.

Specified by:

setAutoSave in interface FileConfiguration

Parameters:

autoSave - true to enable, false to disable

isAutoSave

public boolean isAutoSave()

Description copied from interface: FileConfiguration

Tells if properties are automatically saved to the disk.

Specified by:

isAutoSave in interface FileConfiguration

Returns:

true if auto-saving is enabled, false otherwise

getReloadingStrategy

public ReloadingStrategy getReloadingStrategy()

Description copied from interface: FileConfiguration

Return the reloading strategy.

Specified by:

getReloadingStrategy in interface FileConfiguration

setReloadingStrategy

public void setReloadingStrategy(ReloadingStrategy strategy)

Description copied from interface: FileConfiguration

Set the reloading strategy.

Specified by:

setReloadingStrategy in interface FileConfiguration

reload

public void reload()

Description copied from interface: FileConfiguration

Reload the configuration.

Specified by:

reload in interface FileConfiguration

getEncoding

public String getEncoding()

Description copied from interface: FileConfiguration

Return the encoding used to store the configuration file. If the value is null the default encoding is used.

Specified by:

getEncoding in interface FileConfiguration

setEncoding

public void setEncoding(String encoding)

Description copied from interface: FileConfiguration

Set the encoding used to store the configuration file. Set the encoding to null to use the default encoding.

Specified by:

setEncoding in interface FileConfiguration