ly.img.android.sdk.exif

Class IOUtils

java.lang.Object

ly.img.android.sdk.exif.IOUtils

public class IOUtils
extends java.lang.Object

General IO stream manipulation utilities.

This class provides static utility methods for input/output operations.

• closeQuietly - these methods close a stream ignoring nulls and exceptions
• toXxx/read - these methods read data from a stream
• write - these methods write data to a stream
• copy - these methods copy all the data from one stream to another
• contentEquals - these methods compare the content of two streams

The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production.

All the methods in this class that read a stream are buffered internally. This means that there is no cause to use a BufferedInputStream or BufferedReader. The default buffer size of 4K has been shown to be efficient in tests.

Wherever possible, the methods in this class do not flush or close the stream. This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use.

Origin of code: Excalibur.

Field Summary

Fields

Modifier and Type	Field and Description
static char	DIR_SEPARATOR The system directory separator character.
static char	DIR_SEPARATOR_UNIX The Unix directory separator character.
static char	DIR_SEPARATOR_WINDOWS The Windows directory separator character.
static java.lang.String	LINE_SEPARATOR The system line separator string.
static java.lang.String	LINE_SEPARATOR_UNIX The Unix line separator string.
static java.lang.String	LINE_SEPARATOR_WINDOWS The Windows line separator string.

Constructor Summary

Constructors

Constructor and Description
IOUtils() Instances should NOT be constructed in standard programming.

Method Summary

Modifier and Type	Method and Description
static void	closeQuietly(java.io.InputStream input) Unconditionally close an InputStream.
static void	closeQuietly(java.io.OutputStream output) Unconditionally close an OutputStream.
static int	copy(java.io.InputStream input, java.io.OutputStream output) Copy bytes from an InputStream to an OutputStream.
static void	copy(java.io.InputStream input, java.io.Writer output) Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.
static void	copy(java.io.InputStream input, java.io.Writer output, java.lang.String encoding) Copy bytes from an InputStream to chars on a Writer using the specified character encoding.
static void	copy(java.io.Reader input, java.io.OutputStream output) Copy chars from a Reader to bytes on an OutputStream using the default character encoding of the platform, and calling flush.
static void	copy(java.io.Reader input, java.io.OutputStream output, java.lang.String encoding) Copy chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.
static int	copy(java.io.Reader input, java.io.Writer output) Copy chars from a Reader to a Writer.
static long	copyLarge(java.io.InputStream input, java.io.OutputStream output) Copy bytes from a large (over 2GB) InputStream to an OutputStream.
static long	copyLarge(java.io.Reader input, java.io.Writer output) Copy chars from a large (over 2GB) Reader to a Writer.
static java.lang.String	toString(java.io.InputStream input) Get the contents of an InputStream as a String using the default character encoding of the platform.
static java.lang.String	toString(java.io.InputStream input, java.lang.String encoding) Get the contents of an InputStream as a String using the specified character encoding.
static java.lang.String	toString(java.io.Reader input) Get the contents of a Reader as a String.
static void	write(byte[] data, java.io.OutputStream output) Writes bytes from a byte[] to an OutputStream.
static void	write(byte[] data, java.io.Writer output) Writes bytes from a byte[] to chars on a Writer using the default character encoding of the platform.
static void	write(byte[] data, java.io.Writer output, java.lang.String encoding) Writes bytes from a byte[] to chars on a Writer using the specified character encoding.
static void	write(char[] data, java.io.OutputStream output) Writes chars from a char[] to bytes on an OutputStream.
static void	write(char[] data, java.io.OutputStream output, java.lang.String encoding) Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.
static void	write(char[] data, java.io.Writer output) Writes chars from a char[] to a Writer using the default character encoding of the platform.
static void	write(java.lang.StringBuffer data, java.io.OutputStream output) Writes chars from a StringBuffer to bytes on an OutputStream using the default character encoding of the platform.
static void	write(java.lang.StringBuffer data, java.io.OutputStream output, java.lang.String encoding) Writes chars from a StringBuffer to bytes on an OutputStream using the specified character encoding.
static void	write(java.lang.StringBuffer data, java.io.Writer output) Writes chars from a StringBuffer to a Writer.
static void	write(java.lang.String data, java.io.OutputStream output) Writes chars from a String to bytes on an OutputStream using the default character encoding of the platform.
static void	write(java.lang.String data, java.io.OutputStream output, java.lang.String encoding) Writes chars from a String to bytes on an OutputStream using the specified character encoding.
static void	write(java.lang.String data, java.io.Writer output) Writes chars from a String to a Writer.

Methods inherited from class java.lang.Object

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

Field Detail

DIR_SEPARATOR

public static final char DIR_SEPARATOR

The system directory separator character.

DIR_SEPARATOR_UNIX

public static final char DIR_SEPARATOR_UNIX

The Unix directory separator character.

See Also:

Constant Field Values

DIR_SEPARATOR_WINDOWS

public static final char DIR_SEPARATOR_WINDOWS

The Windows directory separator character.

See Also:

Constant Field Values

LINE_SEPARATOR

public static final java.lang.String LINE_SEPARATOR

The system line separator string.

LINE_SEPARATOR_UNIX

public static final java.lang.String LINE_SEPARATOR_UNIX

The Unix line separator string.

See Also:

Constant Field Values

LINE_SEPARATOR_WINDOWS

public static final java.lang.String LINE_SEPARATOR_WINDOWS

The Windows line separator string.

See Also:

Constant Field Values

Constructor Detail

IOUtils

public IOUtils()

Instances should NOT be constructed in standard programming.

Method Detail

closeQuietly

public static void closeQuietly(java.io.InputStream input)

Unconditionally close an InputStream.

Equivalent to InputStream.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Parameters:

input - the InputStream to close, may be null or already closed

closeQuietly

public static void closeQuietly(java.io.OutputStream output)

Unconditionally close an OutputStream.

Equivalent to OutputStream.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Parameters:

output - the OutputStream to close, may be null or already closed

copy

public static int copy(java.io.InputStream input,
                       java.io.OutputStream output)
                throws java.io.IOException

Copy bytes from an InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Large streams (over 2GB) will return a bytes copied value of -1 after the copy has completed since the correct number of bytes cannot be returned as an int. For large streams use the copyLarge(InputStream, OutputStream) method.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

java.lang.ArithmeticException - if the byte count is too large

Since:

Commons IO 1.1

copy

public static void copy(java.io.InputStream input,
                        java.io.Writer output)
                 throws java.io.IOException

Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read from

output - the Writer to write to

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static void copy(java.io.InputStream input,
                        java.io.Writer output,
                        java.lang.String encoding)
                 throws java.io.IOException

Copy bytes from an InputStream to chars on a Writer using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Character encoding names can be found at IANA.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read from

output - the Writer to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static void copy(java.io.Reader input,
                        java.io.OutputStream output)
                 throws java.io.IOException

Copy chars from a Reader to bytes on an OutputStream using the default character encoding of the platform, and calling flush.

This method buffers the input internally, so there is no need to use a BufferedReader.

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

input - the Reader to read from

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static void copy(java.io.Reader input,
                        java.io.OutputStream output,
                        java.lang.String encoding)
                 throws java.io.IOException

Copy chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.

This method buffers the input internally, so there is no need to use a BufferedReader.

Character encoding names can be found at IANA.

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

input - the Reader to read from

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static int copy(java.io.Reader input,
                       java.io.Writer output)
                throws java.io.IOException

Copy chars from a Reader to a Writer.

This method buffers the input internally, so there is no need to use a BufferedReader.

Large streams (over 2GB) will return a chars copied value of -1 after the copy has completed since the correct number of chars cannot be returned as an int. For large streams use the copyLarge(Reader, Writer) method.

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

java.lang.ArithmeticException - if the character count is too large

Since:

Commons IO 1.1

copyLarge

public static long copyLarge(java.io.InputStream input,
                             java.io.OutputStream output)
                      throws java.io.IOException

Copy bytes from a large (over 2GB) InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.3

copyLarge

public static long copyLarge(java.io.Reader input,
                             java.io.Writer output)
                      throws java.io.IOException

Copy chars from a large (over 2GB) Reader to a Writer.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.3

toString

public static java.lang.String toString(java.io.InputStream input)
                                 throws java.io.IOException

Get the contents of an InputStream as a String using the default character encoding of the platform.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

java.io.IOException - if an I/O error occurs

toString

public static java.lang.String toString(java.io.InputStream input,
                                        java.lang.String encoding)
                                 throws java.io.IOException

Get the contents of an InputStream as a String using the specified character encoding.

Character encoding names can be found at IANA.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

encoding - the encoding to use, null means platform default

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

java.io.IOException - if an I/O error occurs

toString

public static java.lang.String toString(java.io.Reader input)
                                 throws java.io.IOException

Get the contents of a Reader as a String.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

input - the Reader to read from

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

java.io.IOException - if an I/O error occurs

write

public static void write(byte[] data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes bytes from a byte[] to an OutputStream.

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(byte[] data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes bytes from a byte[] to chars on a Writer using the default character encoding of the platform.

This method uses String.String(byte[]).

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(byte[] data,
                         java.io.Writer output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes bytes from a byte[] to chars on a Writer using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.String(byte[], String).

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the Writer to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(char[] data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes chars from a char[] to bytes on an OutputStream.

This method uses String.String(char[]) and String.getBytes().

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(char[] data,
                         java.io.OutputStream output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.String(char[]) and String.getBytes(String).

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(char[] data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes chars from a char[] to a Writer using the default character encoding of the platform.

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(java.lang.StringBuffer data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes chars from a StringBuffer to bytes on an OutputStream using the default character encoding of the platform.

This method uses String.getBytes().

Parameters:

data - the StringBuffer to write, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(java.lang.StringBuffer data,
                         java.io.OutputStream output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes chars from a StringBuffer to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the StringBuffer to write, null ignored

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(java.lang.StringBuffer data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes chars from a StringBuffer to a Writer.

Parameters:

data - the StringBuffer to write, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(java.lang.String data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes chars from a String to bytes on an OutputStream using the default character encoding of the platform.

This method uses String.getBytes().

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(java.lang.String data,
                         java.io.OutputStream output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes chars from a String to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(java.lang.String data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes chars from a String to a Writer.

Parameters:

data - the String to write, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1