Package org.apache.commons.configuration

Class ConfigurationUtils

java.lang.Object

org.apache.commons.configuration.ConfigurationUtils

public final class ConfigurationUtils
extends java.lang.Object

Miscellaneous utility methods for configurations.

Version:

$Id: ConfigurationUtils.java 1208795 2011-11-30 21:18:17Z oheger $

Author:

Herve Quiroz, Emmanuel Bourg

See Also:

Utility methods to convert configurations.

Method Summary

Modifier and Type	Method	Description
static void	append(Configuration source, Configuration target)	Append all properties from the source configuration to the target configuration.
static Configuration	cloneConfiguration(Configuration config)	Clones the given configuration object if this is possible.
static HierarchicalConfiguration	convertToHierarchical(Configuration conf)	Converts the passed in configuration to a hierarchical one.
static HierarchicalConfiguration	convertToHierarchical(Configuration conf, ExpressionEngine engine)	Converts the passed in Configuration object to a hierarchical one using the specified ExpressionEngine.
static void	copy(Configuration source, Configuration target)	Copy all properties from the source configuration to the target configuration.
static void	dump(Configuration configuration, java.io.PrintStream out)	Dump the configuration key/value mappings to some ouput stream.
static void	dump(Configuration configuration, java.io.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 java.io.File	fileFromURL(java.net.URL url)	Tries to convert the specified URL to a file object.
static java.io.File	getFile(java.lang.String basePath, java.lang.String fileName)	Tries to convert the specified base path and file name into a file object.
static java.net.URL	getURL(java.lang.String basePath, java.lang.String file)	Constructs a URL from a base path and a file name.
static java.net.URL	locate(java.lang.String name)	Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.
static java.net.URL	locate(java.lang.String base, java.lang.String name)	Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.
static java.net.URL	locate(FileSystem fileSystem, java.lang.String base, java.lang.String name)	Return the location of the specified resource by searching the user home directory, the current classpath and the system classpath.
static java.lang.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

Method Detail

dump

public static void dump(Configuration configuration,
                        java.io.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,
                        java.io.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 java.lang.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 is not able to handle some specifics of configurations derived from AbstractConfiguration (e.g. list delimiters). For a full support of all of these features the copy() method of AbstractConfiguration should be used. In a future release this method might become deprecated.

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.

Note: This method is not able to handle some specifics of configurations derived from AbstractConfiguration (e.g. list delimiters). For a full support of all of these features the copy() method of AbstractConfiguration should be used. In a future release this method might become deprecated.

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

convertToHierarchical

public static HierarchicalConfiguration convertToHierarchical(Configuration conf,
                                                              ExpressionEngine engine)

Converts the passed in Configuration object to a hierarchical one using the specified ExpressionEngine. This conversion works by adding the keys found in the configuration to a newly created hierarchical configuration. When adding new keys to a hierarchical configuration the keys are interpreted by its ExpressionEngine. If they contain special characters (e.g. brackets) that are treated in a special way by the default expression engine, it may be necessary using a specific engine that can deal with such characters. Otherwise null can be passed in for the ExpressionEngine; then the default expression engine is used. If the passed in configuration is already hierarchical, it is directly returned. (However, the ExpressionEngine is set if it is not null.) Otherwise all properties are copied into a new hierarchical configuration.

Parameters:

conf - the configuration to convert

engine - the ExpressionEngine for the hierarchical configuration or null for the default

Returns:

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

Since:

1.6

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

getURL

public static java.net.URL getURL(java.lang.String basePath,
                                  java.lang.String file)
                           throws java.net.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:

java.net.MalformedURLException - if URLs are invalid

locate

public static java.net.URL locate(java.lang.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 java.net.URL locate(java.lang.String base,
                                  java.lang.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

locate

public static java.net.URL locate(FileSystem fileSystem,
                                  java.lang.String base,
                                  java.lang.String name)

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

Parameters:

fileSystem - the FileSystem to use.

base - the base path of the resource

name - the name of the resource

Returns:

the location of the resource

getFile

public static java.io.File getFile(java.lang.String basePath,
                                   java.lang.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 java.io.File fileFromURL(java.net.URL url)

Tries to convert the specified URL to a file object. If this fails, null is returned. Note: This code has been copied from the FileUtils class from Commons IO.

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