org.apache.commons.configuration
Class ConfigurationUtils

java.lang.Object
  org.apache.commons.configuration.ConfigurationUtils

public final class ConfigurationUtils
extends Object

Miscellaneous utility methods for configurations.

Version:

$Revision: 503227 $, $Date: 2007-02-03 17:19:15 +0100 (Sa, 03 Feb 2007) $

Author:

Herve Quiroz, Oliver Heger, Emmanuel Bourg

See Also:

Utility methods to convert configurations.

Field Summary

(package private) static String	PROTOCOL_FILE Constant for the file URL protocol.
(package private) static String	RESOURCE_PATH_SEPARATOR Constant for the resource path separator.

Method Summary

static void	append(Configuration source, Configuration target) Append all properties from the source configuration to the target configuration.
(package private) static Object	clone(Object obj) An internally used helper method for cloning objects.
static Configuration	cloneConfiguration(Configuration config) Clones the given configuration object if this is possible.
(package private) static File	constructFile(String basePath, String fileName) Helper method for constructing a file object from a base path and a file name.
static HierarchicalConfiguration	convertToHierarchical(Configuration conf) Converts the passed in configuration to a hierarchical one.
static void	copy(Configuration source, Configuration target) Copy all properties from the source configuration to the target configuration.
static void	dump(Configuration configuration, PrintStream out) Dump the configuration key/value mappings to some ouput stream.
static void	dump(Configuration configuration, PrintWriter out) Dump the configuration key/value mappings to some writer.
static void	enableRuntimeExceptions(Configuration src) Enables runtime exceptions for the specified configuration object.
static File	fileFromURL(URL url) Tries to convert the specified URL to a file object.
(package private) static String	getBasePath(URL url) Return the path without the file name, for example http://xyz.net/foo/bar.xml results in http://xyz.net/foo/
static File	getFile(String basePath, String fileName) Tries to convert the specified base path and file name into a file object.
(package private) static String	getFileName(URL url) Extract the file name from the specified URL.
static URL	getURL(String basePath, String file) Constructs a URL from a base path and a file name.
static URL	locate(String name) Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.
static URL	locate(String base, String name) Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.
(package private) static URL	locateFromClasspath(String resourceName) Tries to find a resource with the given name in the classpath.
static String	toString(Configuration configuration) Get a string representation of the key/value mappings of a configuration.

Methods inherited from class java.lang.Object

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

Field Detail

PROTOCOL_FILE

static final String PROTOCOL_FILE

Constant for the file URL protocol.

See Also:

Constant Field Values

RESOURCE_PATH_SEPARATOR

static final String RESOURCE_PATH_SEPARATOR

Constant for the resource path separator.

See Also:

Constant Field Values

Method Detail

dump

public static void dump(Configuration configuration,
                        PrintStream out)

Dump the configuration key/value mappings to some ouput stream.

Parameters:

configuration - the configuration

out - the output stream to dump the configuration to

dump

public static void dump(Configuration configuration,
                        PrintWriter out)

Dump the configuration key/value mappings to some writer.

Parameters:

configuration - the configuration

out - the writer to dump the configuration to

toString

public static String toString(Configuration configuration)

Get a string representation of the key/value mappings of a configuration.

Parameters:

configuration - the configuration

Returns:

a string representation of the configuration

copy

public static void copy(Configuration source,
                        Configuration target)

Copy all properties from the source configuration to the target configuration. Properties in the target configuration are replaced with the properties with the same key in the source configuration. Note: This method won't work well on hierarchical configurations because it is not able to copy information about the properties' structure. So when dealing with hierarchical configuration objects their clone() methods should be used.

Parameters:

source - the source configuration

target - the target configuration

Since:

1.1

append

public static void append(Configuration source,
                          Configuration target)

Append all properties from the source configuration to the target configuration. Properties in the source configuration are appended to the properties with the same key in the target configuration.

Parameters:

source - the source configuration

target - the target configuration

Since:

1.1

convertToHierarchical

public static HierarchicalConfiguration convertToHierarchical(Configuration conf)

Converts the passed in configuration to a hierarchical one. If the configuration is already hierarchical, it is directly returned. Otherwise all properties are copied into a new hierarchical configuration.

Parameters:

conf - the configuration to convert

Returns:

the new hierarchical configuration (the result is null if and only if the passed in configuration is null)

Since:

1.3

cloneConfiguration

public static Configuration cloneConfiguration(Configuration config)
                                        throws ConfigurationRuntimeException

Clones the given configuration object if this is possible. If the passed in configuration object implements the Cloneable interface, its clone() method will be invoked. Otherwise an exception will be thrown.

Parameters:

config - the configuration object to be cloned (can be null)

Returns:

the cloned configuration (null if the argument was null, too)

Throws:

ConfigurationRuntimeException - if cloning is not supported for this object

Since:

1.3

clone

static Object clone(Object obj)
             throws CloneNotSupportedException

An internally used helper method for cloning objects. This implementation is not very sophisticated nor efficient. Maybe it can be replaced by an implementation from Commons Lang later. The method checks whether the passed in object implements the Cloneable interface. If this is the case, the clone() method is invoked by reflection. Errors that occur during the cloning process are re-thrown as runtime exceptions.

Parameters:

obj - the object to be cloned

Returns:

the cloned object

Throws:

CloneNotSupportedException - if the object cannot be cloned

getURL

public static URL getURL(String basePath,
                         String file)
                  throws MalformedURLException

Constructs a URL from a base path and a file name. The file name can be absolute, relative or a full URL. If necessary the base path URL is applied.

Parameters:

basePath - the base path URL (can be null)

file - the file name

Returns:

the resulting URL

Throws:

MalformedURLException - if URLs are invalid

constructFile

static File constructFile(String basePath,
                          String fileName)

Helper method for constructing a file object from a base path and a file name. This method is called if the base path passed to getURL() does not seem to be a valid URL.

Parameters:

basePath - the base path

fileName - the file name

Returns:

the resulting file

locate

public static URL locate(String name)

Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.

Parameters:

name - the name of the resource

Returns:

the location of the resource

locate

public static URL locate(String base,
                         String name)

Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.

Parameters:

base - the base path of the resource

name - the name of the resource

Returns:

the location of the resource

locateFromClasspath

static URL locateFromClasspath(String resourceName)

Tries to find a resource with the given name in the classpath.

Parameters:

resourceName - the name of the resource

Returns:

the URL to the found resource or null if the resource cannot be found

getBasePath

static String getBasePath(URL url)

Return the path without the file name, for example http://xyz.net/foo/bar.xml results in http://xyz.net/foo/

Parameters:

url - the URL from which to extract the path

Returns:

the path component of the passed in URL

getFileName

static String getFileName(URL url)

Extract the file name from the specified URL.

Parameters:

url - the URL from which to extract the file name

Returns:

the extracted file name

getFile

public static File getFile(String basePath,
                           String fileName)

Tries to convert the specified base path and file name into a file object. This method is called e.g. by the save() methods of file based configurations. The parameter strings can be relative files, absolute files and URLs as well. This implementation checks first whether the passed in file name is absolute. If this is the case, it is returned. Otherwise further checks are performed whether the base path and file name can be combined to a valid URL or a valid file name. Note: The test if the passed in file name is absolute is performed using java.io.File.isAbsolute(). If the file name starts with a slash, this method will return true on Unix, but false on Windows. So to ensure correct behavior for relative file names on all platforms you should never let relative paths start with a slash. E.g. in a configuration definition file do not use something like that:

 <properties fileName="/subdir/my.properties"/>
 

Under Windows this path would be resolved relative to the configuration definition file. Under Unix this would be treated as an absolute path name.

Parameters:

basePath - the base path

fileName - the file name

Returns:

the file object (null if no file can be obtained)

fileFromURL

public static File fileFromURL(URL url)

Tries to convert the specified URL to a file object. If this fails, null is returned.

Parameters:

url - the URL

Returns:

the resulting file object

enableRuntimeExceptions

public static void enableRuntimeExceptions(Configuration src)

Enables runtime exceptions for the specified configuration object. This method can be used for configuration implementations that may face errors on normal property access, e.g. DatabaseConfiguration or JNDIConfiguration. Per default such errors are simply logged and then ignored. This implementation will register a special ConfigurationErrorListener that throws a runtime exception (namely a ConfigurationRuntimeException) on each received error event.

Parameters:

src - the configuration, for which runtime exceptions are to be enabled; this configuration must be derived from EventSource