Package oshi.util

Class FileUtil

java.lang.Object

oshi.util.FileUtil

@ThreadSafe
public final class FileUtil
extends Object

File reading methods

Method Summary

Modifier and Type	Method	Description
static int	getIntFromFile(String filename)	Read a file and return the int value contained therein.
static Map<String,String>	getKeyValueMapFromFile(String filename, String separator)	Read a file and return a map of string keys to string values contained therein.
static long	getLongFromFile(String filename)	Read a file and return the long value contained therein.
static String	getStringFromFile(String filename)	Read a file and return the String value contained therein.
static long	getUnsignedLongFromFile(String filename)	Read a file and return the unsigned long value contained therein as a long.
static byte[]	readAllBytes(String filename, boolean reportError)	Read an entire file at one time.
static ByteBuffer	readAllBytesAsBuffer(String filename)	Read an entire file at one time.
static void	readByteArrayFromBuffer(ByteBuffer buff, byte[] array)	Reads a byte array value from a ByteBuffer
static byte	readByteFromBuffer(ByteBuffer buff)	Reads a byte value from a ByteBuffer
static List<String>	readFile(String filename)	Read an entire file at one time.
static List<String>	readFile(String filename, boolean reportError)	Read an entire file at one time.
static byte[]	readFileAsBytes(URL url)	Reads a URL into a byte array
static int	readIntFromBuffer(ByteBuffer buff)	Reads an int value from a ByteBuffer
static List<String>	readLines(String filename, int count)	Read count lines from a file.
static List<String>	readLines(String filename, int count, boolean reportError)	Read count lines from a file.
static long	readLongFromBuffer(ByteBuffer buff)	Reads a long value from a ByteBuffer
static com.sun.jna.NativeLong	readNativeLongFromBuffer(ByteBuffer buff)	Reads a NativeLong value from a ByteBuffer
static com.sun.jna.Pointer	readPointerFromBuffer(ByteBuffer buff)	Reads a Pointer value from a ByteBuffer
static Properties	readPropertiesFromFilename(String propsFilename)	Read a configuration file from the sequence of context classloader, system classloader and classloader of the current class, and return its properties
static short	readShortFromBuffer(ByteBuffer buff)	Reads a short value from a ByteBuffer
static com.sun.jna.platform.unix.LibCAPI.size_t	readSizeTFromBuffer(ByteBuffer buff)	Reads a size_t value from a ByteBuffer
static String	readSymlinkTarget(File file)	Reads the target of a symbolic link

Methods inherited from class java.lang.Object

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

Method Details

readFile

public static List<String> readFile(String filename)

Read an entire file at one time. Intended primarily for Linux /proc filesystem to avoid recalculating file contents on iterative reads.

Parameters:

filename - The file to read

Returns:

A list of Strings representing each line of the file, or an empty list if file could not be read or is empty

readFile

public static List<String> readFile(String filename,
 boolean reportError)

Read an entire file at one time. Intended primarily for Linux /proc filesystem to avoid recalculating file contents on iterative reads.

Parameters:

filename - The file to read

reportError - Whether to log errors reading the file

Returns:

A list of Strings representing each line of the file, or an empty list if file could not be read or is empty

readLines

public static List<String> readLines(String filename,
 int count)

Read count lines from a file. Intended primarily for Linux /proc filesystem to avoid recalculating file contents on iterative reads.

Parameters:

filename - The file to read

count - The number of lines to read

Returns:

A list of Strings representing the first count lines of the file, or an empty list if file could not be read or is empty

readLines

public static List<String> readLines(String filename,
 int count,
 boolean reportError)

Read count lines from a file. Intended primarily for Linux /proc filesystem to avoid recalculating file contents on iterative reads.

Parameters:

filename - The file to read

count - The number of lines to read

reportError - Whether to log errors reading the file

Returns:

A list of Strings representing the first count lines of the file, or an empty list if file could not be read or is empty

readAllBytes

public static byte[] readAllBytes(String filename,
 boolean reportError)

Read an entire file at one time. Intended primarily for Linux /proc filesystem to avoid recalculating file contents on iterative reads.

Parameters:

filename - The file to read

reportError - Whether to log errors reading the file

Returns:

A byte array representing the file

readAllBytesAsBuffer

public static ByteBuffer readAllBytesAsBuffer(String filename)

Read an entire file at one time. Intended for unix /proc binary files to avoid reading file contents on iterative reads.

Parameters:

filename - The file to read

Returns:

A bytebuffer representing the file if read was successful; null otherwise

readByteFromBuffer

public static byte readByteFromBuffer(ByteBuffer buff)

Reads a byte value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next byte value

readShortFromBuffer

public static short readShortFromBuffer(ByteBuffer buff)

Reads a short value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next short value

readIntFromBuffer

public static int readIntFromBuffer(ByteBuffer buff)

Reads an int value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next int value

readLongFromBuffer

public static long readLongFromBuffer(ByteBuffer buff)

Reads a long value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next long value

readNativeLongFromBuffer

public static com.sun.jna.NativeLong readNativeLongFromBuffer(ByteBuffer buff)

Reads a NativeLong value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next value

readSizeTFromBuffer

public static com.sun.jna.platform.unix.LibCAPI.size_t readSizeTFromBuffer(ByteBuffer buff)

Reads a size_t value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next value

readByteArrayFromBuffer

public static void readByteArrayFromBuffer(ByteBuffer buff,
 byte[] array)

Reads a byte array value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

array - The array into which to read the data

readPointerFromBuffer

public static com.sun.jna.Pointer readPointerFromBuffer(ByteBuffer buff)

Reads a Pointer value from a ByteBuffer

Parameters:

buff - The bytebuffer to read from

Returns:

The next value

getLongFromFile

public static long getLongFromFile(String filename)

Read a file and return the long value contained therein. Intended primarily for Linux /sys filesystem

Parameters:

filename - The file to read

Returns:

The value contained in the file, if any; otherwise zero

getUnsignedLongFromFile

public static long getUnsignedLongFromFile(String filename)

Read a file and return the unsigned long value contained therein as a long. Intended primarily for Linux /sys filesystem

Parameters:

filename - The file to read

Returns:

The value contained in the file, if any; otherwise zero

getIntFromFile

public static int getIntFromFile(String filename)

Read a file and return the int value contained therein. Intended primarily for Linux /sys filesystem

Parameters:

filename - The file to read

Returns:

The value contained in the file, if any; otherwise zero

getStringFromFile

public static String getStringFromFile(String filename)

Read a file and return the String value contained therein. Intended primarily for Linux /sys filesystem

Parameters:

filename - The file to read

Returns:

The value contained in the file, if any; otherwise empty string

getKeyValueMapFromFile

public static Map<String,String> getKeyValueMapFromFile(String filename,
 String separator)

Read a file and return a map of string keys to string values contained therein. Intended primarily for Linux /proc/[pid] files to provide more detailed or accurate information not available in the API.

Parameters:

filename - The file to read

separator - Character(s) in each line of the file that separate the key and the value.

Returns:

The map contained in the file, delimited by the separator, with the value whitespace trimmed. If keys and values are not parsed, an empty map is returned.

readPropertiesFromFilename

public static Properties readPropertiesFromFilename(String propsFilename)

Read a configuration file from the sequence of context classloader, system classloader and classloader of the current class, and return its properties

Parameters:

propsFilename - The filename

Returns:

A Properties object containing the properties.

readFileAsBytes

public static byte[] readFileAsBytes(URL url)
                              throws IOException

Reads a URL into a byte array

Parameters:

url - The URL of the file to read

Returns:

the byte content of the file

Throws:

IOException - on file reading failure

readSymlinkTarget

public static String readSymlinkTarget(File file)

Reads the target of a symbolic link

Parameters:

file - The file to read

Returns:

The symlink name, or null if the read failed