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public class

InputStreamReader

extends Reader
java.lang.Object
   ↳ java.io.Reader
     ↳ java.io.InputStreamReader
Known Direct Subclasses

Class Overview

InputStreamReader is class for turning a byte Stream into a character Stream. Data read from the source input stream is converted into characters by either a default or provided character converter. By default, the encoding is assumed to ISO8859_1. The InputStreamReader contains a buffer of bytes read from the source input stream and converts these into characters as needed. The buffer size is 8K.

See Also

Summary

[Expand]
Inherited Fields
From class java.io.Reader
Public Constructors
InputStreamReader(InputStream in)
Constructs a new InputStreamReader on the InputStream in.
InputStreamReader(InputStream in, String enc)
Constructs a new InputStreamReader on the InputStream in.
InputStreamReader(InputStream in, CharsetDecoder dec)
Constructs a new InputStreamReader on the InputStream in and CharsetDecoder dec.
InputStreamReader(InputStream in, Charset charset)
Constructs a new InputStreamReader on the InputStream in and Charset charset.
Public Methods
void close()
Close this InputStreamReader.
String getEncoding()
Answer the String which identifies the encoding used to convert bytes to characters.
int read(char[] buf, int offset, int length)
Reads at most count characters from this Reader and stores them at offset in the character array buf.
int read()
Reads a single character from this InputStreamReader and returns the result as an int.
boolean ready()
Returns a boolean indicating whether or not this InputStreamReader is ready to be read without blocking.
[Expand]
Inherited Methods
From class java.io.Reader
From class java.lang.Object
From interface java.io.Closeable
From interface java.lang.Readable

Public Constructors

public InputStreamReader (InputStream in)

Constructs a new InputStreamReader on the InputStream in. Now character reading can be filtered through this InputStreamReader. This constructor assumes the default conversion of ISO8859_1 (ISO-Latin-1).

Parameters
in the InputStream to convert to characters.

public InputStreamReader (InputStream in, String enc)

Constructs a new InputStreamReader on the InputStream in. Now character reading can be filtered through this InputStreamReader. This constructor takes a String parameter enc which is the name of an encoding. If the encoding cannot be found, an UnsupportedEncodingException error is thrown.

Parameters
in the InputStream to convert to characters.
enc a String describing the character converter to use.
Throws
UnsupportedEncodingException if the encoding cannot be found.

public InputStreamReader (InputStream in, CharsetDecoder dec)

Constructs a new InputStreamReader on the InputStream in and CharsetDecoder dec. Now character reading can be filtered through this InputStreamReader.

Parameters
in the InputStream to convert to characters
dec a CharsetDecoder used by the character conversion

public InputStreamReader (InputStream in, Charset charset)

Constructs a new InputStreamReader on the InputStream in and Charset charset. Now character reading can be filtered through this InputStreamReader.

Parameters
in the InputStream to convert to characters
charset the Charset that specify the character converter

Public Methods

public void close ()

Close this InputStreamReader. This implementation closes the source InputStream and releases all local storage.

Throws
IOException If an error occurs attempting to close this InputStreamReader.

public String getEncoding ()

Answer the String which identifies the encoding used to convert bytes to characters. The value null is returned if this Reader has been closed.

Returns
  • the String describing the converter or null if this Reader is closed.

public int read (char[] buf, int offset, int length)

Reads at most count characters from this Reader and stores them at offset in the character array buf. Returns the number of characters actually read or -1 if the end of reader was encountered. The bytes are either obtained from converting bytes in this readers buffer or by first filling the buffer from the source InputStream and then reading from the buffer.

Parameters
buf character array to store the read characters
offset offset in buf to store the read characters
length maximum number of characters to read
Returns
  • the number of characters read or -1 if end of reader.
Throws
IOException If the InputStreamReader is already closed or some other IO error occurs.

public int read ()

Reads a single character from this InputStreamReader and returns the result as an int. The 2 higher-order characters are set to 0. If the end of reader was encountered then return -1. The byte value is either obtained from converting bytes in this readers buffer or by first filling the buffer from the source InputStream and then reading from the buffer.

Returns
  • the character read or -1 if end of reader.
Throws
IOException If the InputStreamReader is already closed or some other IO error occurs.

public boolean ready ()

Returns a boolean indicating whether or not this InputStreamReader is ready to be read without blocking. If the result is true, the next read() will not block. If the result is false this Reader may or may not block when read() is sent. This implementation returns true if there are bytes available in the buffer or the source InputStream has bytes available.

Returns
  • true if the receiver will not block when read() is called, false if unknown or blocking will occur.
Throws
IOException If the InputStreamReader is already closed or some other IO error occurs.