org.arp.javautil.io

Class IOUtil

java.lang.Object

org.arp.javautil.io.IOUtil

public final class IOUtil
extends Object

Convenience routines for reading files, resources, readers, and input streams.

Author:

Andrew Post

Method Summary

Modifier and Type	Method and Description
static Properties	createPropertiesFromResource(Class<?> classObj, String resourceName) Creates a Properties objects and loads the data in the given resource, using the given class' getResourceAsStream method.
static InputStream	getResourceAsStream(String name) Finds a resource with a given name, using this class' class loader.
static InputStream	getResourceAsStream(String name, Class<?> cls) Finds a resource with a given name using the class loader of the specified class.
static String	getUserInput(String prompt)
static Properties	loadPropertiesFromResource(Class<?> cls, String resource)
static Properties[]	loadPropertiesFromResources(Class<?> cls, String[] resources)
static void	readPropertiesFromResource(Properties properties, Class<?> classObj, String resourceName) Loads properties from the given resource into the given properties object.
static List<String>	readResourceAsLines(Class<?> classObj, String resourceName) Reads everything from a textual resource as lines using the default character set.
static String	readResourceAsString(Class<?> classObj, String resourceName) Reads everything from the given resource into a String using the default character set.
static File	resourceToFile(String resourceName, String filePrefix, String fileSuffix) Converts a resource into a temporary file that can be read by objects that look up files by name.

Methods inherited from class java.lang.Object

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

Method Detail

readResourceAsString

public static String readResourceAsString(Class<?> classObj,
                                          String resourceName)
                                   throws IOException

Reads everything from the given resource into a String using the default character set.

Parameters:

classObj - the Class from which Class.getResourceAsStream is invoked. If null, will use IOUtil.class.

resourceName - a resource name String.

Returns:

a String, or null if resourceName is null.

Throws:

IOException - if the resource cannot be found or if there is an error reading from it.

readResourceAsLines

public static List<String> readResourceAsLines(Class<?> classObj,
                                               String resourceName)
                                        throws IOException

Reads everything from a textual resource as lines using the default character set.

Parameters:

classObj - the Class from which Class.getResourceAsStream is invoked. If null, will use IOUtil.class.

resourceName - a resource name String.

Returns:

a String, or null if resourceName is null.

Throws:

IOException - if the resource cannot be found or if there is an error reading from it.

readPropertiesFromResource

public static void readPropertiesFromResource(Properties properties,
                                              Class<?> classObj,
                                              String resourceName)
                                       throws IOException

Loads properties from the given resource into the given properties object.

Parameters:

properties - the Properties, using the given class' getResourceAsStream method.

classObj - the Class whose getResourceAsStream method is called, cannot be null.

resourceName - a resource String, visible * * from classObj's class loader. If null, this method does nothing.

Throws:

IOException - if an error occurred reading the resource.

createPropertiesFromResource

public static Properties createPropertiesFromResource(Class<?> classObj,
                                                      String resourceName)
                                               throws IOException

Creates a Properties objects and loads the data in the given resource, using the given class' getResourceAsStream method.

Parameters:

classObj - the Class whose getResourceAsStream method is called, cannot be null.

resourceName - a resource String, visible * * from classObj's class loader. If null, this methods returns an empty Properties object.

Returns:

a Properties object.

Throws:

IOException

getUserInput

public static String getUserInput(String prompt)
                           throws IOException

Throws:

IOException

loadPropertiesFromResource

public static Properties loadPropertiesFromResource(Class<?> cls,
                                                    String resource)
                                             throws IOException

Throws:

IOException

loadPropertiesFromResources

public static Properties[] loadPropertiesFromResources(Class<?> cls,
                                                       String[] resources)
                                                throws IOException

Throws:

IOException

getResourceAsStream

public static InputStream getResourceAsStream(String name)
                                       throws IOException

Finds a resource with a given name, using this class' class loader. Functions identically to Class.getResourceAsStream(java.lang.String), except it throws an IllegalArgumentException if the specified resource name is null, and it throws an IOException if no resource with the specified name is found.

Parameters:

name - name String of the desired resource. Cannot be null.

Returns:

an InputStream.

Throws:

IOException - if no resource with this name is found.

getResourceAsStream

public static InputStream getResourceAsStream(String name,
                                              Class<?> cls)
                                       throws IOException

Finds a resource with a given name using the class loader of the specified class. Functions identically to Class.getResourceAsStream(java.lang.String), except it throws an IllegalArgumentException if the specified resource name is null, and it throws an IOException if no resource with the specified name is found.

Parameters:

name - name String of the desired resource. Cannot be null.

cls - the Class whose loader to use.

Returns:

an InputStream.

Throws:

IOException - if no resource with this name is found.

resourceToFile

public static File resourceToFile(String resourceName,
                                  String filePrefix,
                                  String fileSuffix)
                           throws IOException

Converts a resource into a temporary file that can be read by objects that look up files by name. Returns the file that was created. The file will be deleted when the program exits.

Parameters:

resourceName - the resource to convert. Cannot be null.

filePrefix - the prefix of the temporary file. Cannot be null.

fileSuffix - the suffix of the temporary file.

Returns:

a temporary File.

Throws:

IOException - if an error occurs while writing the contents of the resource to the temporary file.