Class FileUtil
- Version:
- 1.1
- Author:
- Achim Westermann
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Method Summary
Modifier and TypeMethodDescriptionCuts the path information of the String that is interpreted as a filename into the directory part and the file part.cutDirectoryInformation
(URL path) Cuts all path information of the String representation of the given URL.cutExtension
(String filename) Cuts a String into the part before the last dot and after the last dot.static File
deriveFile
(File source, String suffix, boolean preserveExtension) Creates a new file by the contract of
.File.createTempFile(String, String, File)
static String
formatFilesize
(long filesize, Locale locale) Returns the formatted file size to Bytes, KB, MB or GB depending on the given value.static String
getDefaultFileName
(String name) Finds a filename based on the given name.static boolean
isAllASCII
(File f) Tests whether the given file only contains ASCII characters if interpreted by reading bytes (16 bit).static boolean
Tests wether the given input stream only contains ASCII characters if interpreted by reading bytes (16 bit).static boolean
Tests, whether the content of the given file is identical at character level, when it is opened with both different Charsets.static InputStream
InvokesreadRAM(File)
, but decorates the result with aByteArrayInputStream
.static byte[]
Reads the content of the given File into an array.static void
Removes the duplicate line breaks in the given file.
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Method Details
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cutDirectoryInformation
Cuts all path information of the String representation of the given URL."file//c:/work/programming/anyfile.jar" --> "anyfile.jar" "http://jamwg.de" --> "" // No file part. "ftp://files.com/directory2/" --> "" // File part of URL denotes a directory.
Assuming, that '/' is the current file separator character.- Parameters:
path
- the absolute file path you want the mere file name of.- Returns:
- the
consisting of path information and file name.Map.Entry
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cutDirectoryInformation
Cuts the path information of the String that is interpreted as a filename into the directory part and the file part. The current operating system's path separator is used to cut all path information from the String."c:/work/programming/anyfile.jar" --> Map.Entry("c:/work/programming/","anyfile.jar"); "anyfile.jar" --> Map.Entry(new File(".").getAbsolutePath(),"anyfile.jar"); "c:/directory1/directory2/" --> Map.Entry("c:/directory1/directory2/",""); "c:/directory1/directory2" --> Map.Entry("c:/directory1/directory2/",""); // directory2 is a dir! "c:/directory1/file2" --> Map.Entry("c:/directory1/","file2"); // file2 is a file! "c:/" --> Map.Entry("c:/","");
Assuming, that '/' is the current file separator character.If your string is retrieved from an URL instance, use cutDirectoryInformation(URL path) instead, because URL's do not depend on the operating systems file separator!
- Parameters:
path
- the absolute file path you want the mere file name of.- Returns:
- the
consisting of path information and file name.Map.Entry
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cutExtension
Cuts a String into the part before the last dot and after the last dot. If only one dot is contained on the first position, it will completely be used as prefix part.Map.Entry entry = FileUtil.cutExtension("A.Very.Strange.Name.txt"); String prefix = (String) entry.getKey(); // prefix is "A.Very.Strange.Name". String suffix = (String) entry.getValue(); // suffix is "txt"; entry = FileUtil.cutExtension(".profile"); String prefix = (String) entry.getKey(); // prefix is ".profile". String suffix = (String) entry.getValue(); // suffix is ""; entry = FileUtil.cutExtension("bash"); String prefix = (String) entry.getKey(); // prefix is "bash". String suffix = (String) entry.getValue(); // suffix is "";
- Parameters:
filename
- A String that is interpreted to be a file name: The last dot ('.') is interpreted to be the extension delimiter.- Returns:
- A java.util.Map.Entry instance containing a String for the filename at the key side and a String for the extension at the value side.
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getDefaultFileName
Finds a filename based on the given name. If a file with the given name does not exist, name will be returned.Else:
"myFile.out" --> "myFile_0.out" "myFile_0.out" --> "myFile_1.out" "myFile_1.out" --> "myFile_2.out" ....
The potential extension is preserved, but a number is appended to the prefix name.
- Parameters:
name
- A desired file name.- Returns:
- A String that sticks to the naming convention of the given String but is unique in the directory scope of argument name.
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deriveFile
public static File deriveFile(File source, String suffix, boolean preserveExtension) throws IOException Creates a new file by the contract of
.File.createTempFile(String, String, File)
The resulting file will have the full path and file name without the extension concatenated with the given suffix (if preserveExtension is true also the suffix of the original file will be added to the end).
- Parameters:
source
- the source file to take the name of.suffix
- the suffix to append.preserveExtension
- if true the suffix of the source file will be appended to the result file.- Returns:
- A file derived from the original file name.
- Throws:
IOException
- if something goes wrong.
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isAllASCII
Tests whether the given file only contains ASCII characters if interpreted by reading bytes (16 bit).This does not mean that the file is really an ASCII text file. It just might be viewed with an editor showing only valid ASCII characters.
- Parameters:
f
- the file to test.- Returns:
- true if all bytes in the file are in the ASCII range.
- Throws:
IOException
- on a bad day.
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isAllASCII
Tests wether the given input stream only contains ASCII characters if interpreted by reading bytes (16 bit).This does not mean that the underlying content is really an ASCII text file. It just might be viewed with an editor showing only valid ASCII characters.
- Parameters:
in
- the stream to test.- Returns:
- true if all bytes in the given input stream are in the ASCII range.
- Throws:
IOException
- on a bad day.
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isEqual
Tests, whether the content of the given file is identical at character level, when it is opened with both different Charsets.This is most often the case, if the given file only contains ASCII codes but may also occur, when both codepages cover common ranges and the document only contains values m_out of those ranges (like the EUC-CN charset contains all mappings from BIG5).
- Parameters:
document
- the file to test.a
- the first character set to interpret the document in.b
- the 2nd character set to interpret the document in.- Returns:
- true if both files have all equal contents if they are interpreted as character data in both given encodings (they may differ at binary level if both charsets are different).
- Throws:
IOException
- if something goes wrong.
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readCache
InvokesreadRAM(File)
, but decorates the result with aByteArrayInputStream
.This means: The complete content of the given File has been loaded before using the returned InputStream. There are no IO-delays afterwards but OutOfMemoryErrors may occur.
- Parameters:
f
- the file to cache.- Returns:
- an input stream backed by the file read into memory.
- Throws:
IOException
- if something goes wrong.
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readRAM
Reads the content of the given File into an array.This method currently does not check for maximum length and might cause a java.lang.OutOfMemoryError. It is only intended for performance-measurements of data-based algorithms that want to exclude I/O-usage.
- Parameters:
f
- the file to read.- Returns:
- the contents of the given file.
- Throws:
IOException
- if something goes wrong.
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removeDuplicateLineBreaks
Removes the duplicate line breaks in the given file.Be careful with big files: In order to avoid having to write a tmpfile (cannot read and directly write to the same file) a StringBuffer is used for manipulation. Big files will cost all RAM and terminate VM hard.
- Parameters:
f
- the file to remove duplicate line breaks in.
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formatFilesize
Returns the formatted file size to Bytes, KB, MB or GB depending on the given value.- Parameters:
filesize
- in byteslocale
- the locale to translate the result to (e.g. in France they us- Returns:
- the formatted filesize to Bytes, KB, MB or GB depending on the given value.
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