prefuse.util.io
Class IOLib

java.lang.Object
  prefuse.util.io.IOLib

public class IOLib
extends java.lang.Object

Library routines for input/output tasks.

Author:

jeffrey heer

Method Summary

static java.lang.String	getExtension(java.io.File f) Returns the extension for a file or null if there is none
static java.lang.String	getExtension(java.lang.String filename) Returns the extension for a file or null if there is none
static Graph	getGraphFile(java.awt.Component c) Present a file chooser dialog for loading a Graph or Tree data set.
static Table	getTableFile(java.awt.Component c) Present a file chooser dialog for loading a Table data set.
static boolean	isGZipFile(java.lang.String file) Indicates if the given file ends with a file extension of ".gz" or ".Z", indicating a GZip file.
static boolean	isUrlString(java.lang.String s) Indicates if a given String is a URL string.
static boolean	isZipFile(java.lang.String file) Indicates if the given file ends with a file extension of ".zip", indicating a Zip file.
static ByteArrayList	readAsBytes(java.io.InputStream is) Reads an input stream into a list of byte values.
static java.lang.String	readAsString(java.io.InputStream is) Reads an input stream into a single String result.
static java.lang.String	readAsString(java.lang.String location) Reads data pulled from the given location string into a single String result.
static java.io.InputStream	streamFromString(java.lang.String location) Get an input string corresponding to the given location string.
static java.net.URL	urlFromString(java.lang.String location) From a string description, attempt to generate a URL object.
static java.net.URL	urlFromString(java.lang.String location, java.lang.Class referrer, boolean includeFileSystem) From a string description, attempt to generate a URL object.

Methods inherited from class java.lang.Object

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

Method Detail

isUrlString

public static boolean isUrlString(java.lang.String s)

Indicates if a given String is a URL string. Checks to see if the string begins with the "http:/", "ftp:/", or "file:/" protocol strings.

Parameters:

s - the string to check

Returns:

true if a url string matching the listed protocols, false otherwise

urlFromString

public static java.net.URL urlFromString(java.lang.String location)

From a string description, attempt to generate a URL object. The string may point to an Internet location (e.g., http:// or ftp:// URL), a resource on the class path (resulting in a resource URL that points into the current classpath), or a file on the local filesystem (resulting in a file:// URL). The String will be checked in that order in an attempt to resolve it to a valid URL.

Parameters:

location - the location string for which to get a URL object

Returns:

a URL object, or null if the location string could not be resolved

urlFromString

public static java.net.URL urlFromString(java.lang.String location,
                                         java.lang.Class referrer,
                                         boolean includeFileSystem)

From a string description, attempt to generate a URL object. The string may point to an Internet location (e.g., http:// or ftp:// URL), a resource on the class path (resulting in a resource URL that points into the current classpath), or, if the includeFileSystem flag is true, a file on the local filesystem (resulting in a file:// URL). The String will be checked in that order in an attempt to resolve it to a valid URL.

Parameters:

location - the location string for which to get a URL object

referrer - the class to check for classpath resource items, the location string will be resolved against the package/folder containing this class

includeFileSystem - indicates if the file system should be included in the search to resolve the location String

Returns:

a URL object, or null if the location string could not be resolved

streamFromString

public static java.io.InputStream streamFromString(java.lang.String location)
                                            throws java.io.IOException

Get an input string corresponding to the given location string. The string will first be resolved to a URL and an input stream will be requested from the URL connection. If this fails, the location will be resolved against the file system. Also, if a gzip file is found, the input stream will also be wrapped by a GZipInputStream. If the location string can not be resolved, a null value is returned

Parameters:

location - the location string

Returns:

an InputStream for the resolved location string

Throws:

java.io.IOException - if an input/ouput error occurs

getExtension

public static java.lang.String getExtension(java.io.File f)

Returns the extension for a file or null if there is none

Parameters:

f - the input file

Returns:

the file extension, or null if none

isGZipFile

public static boolean isGZipFile(java.lang.String file)

Indicates if the given file ends with a file extension of ".gz" or ".Z", indicating a GZip file.

Parameters:

file - a String of the filename or URL of the file

Returns:

true if the extension is ".gz" or ".Z", false otherwise

isZipFile

public static boolean isZipFile(java.lang.String file)

Indicates if the given file ends with a file extension of ".zip", indicating a Zip file.

Parameters:

file - a String of the filename or URL of the file

Returns:

true if the extension is ".zip", false otherwise

getExtension

public static java.lang.String getExtension(java.lang.String filename)

Returns the extension for a file or null if there is none

Parameters:

filename - the input filename

Returns:

the file extension, or null if none

readAsBytes

public static ByteArrayList readAsBytes(java.io.InputStream is)
                                 throws java.io.IOException

Reads an input stream into a list of byte values.

Parameters:

is - the input stream to read

Returns:

a ByteArrayList containing the contents of the input stream

Throws:

java.io.IOException - if an input/ouput error occurs

readAsString

public static java.lang.String readAsString(java.io.InputStream is)
                                     throws java.io.IOException

Reads an input stream into a single String result.

Parameters:

is - the input stream to read

Returns:

a String containing the contents of the input stream

Throws:

java.io.IOException - if an input/ouput error occurs

readAsString

public static java.lang.String readAsString(java.lang.String location)
                                     throws java.io.IOException

Reads data pulled from the given location string into a single String result. The method attempts to retrieve an InputStream using the streamFromString(String) method, then read the input stream into a String result.

Parameters:

location - the location String

Returns:

a String with the requested data

Throws:

java.io.IOException - if an input/ouput error occurs

See Also:

streamFromString(String)

getTableFile

public static Table getTableFile(java.awt.Component c)

Present a file chooser dialog for loading a Table data set.

Parameters:

c - user interface component from which the request is being made

Returns:

a newly loaded Table, or null if not found or action canceled

getGraphFile

public static Graph getGraphFile(java.awt.Component c)

Present a file chooser dialog for loading a Graph or Tree data set.

Parameters:

c - user interface component from which the request is being made

Returns:

a newly loaded Graph, or null if not found or action canceled