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public abstract class

InputStream

extends Object
implements Closeable
java.lang.Object
   ↳ java.io.InputStream
Known Direct Subclasses
Known Indirect Subclasses

Class Overview

InputStream is an abstract class for all byte input streams. It provides basic method implementations for reading bytes from a stream.

See Also

Summary

Public Constructors
InputStream()
This constructor does nothing interesting.
Public Methods
int available()
Returns a int representing then number of bytes that are available before this InputStream will block.
void close()
Close the InputStream.
void mark(int readlimit)
Set a Mark position in this InputStream.
boolean markSupported()
Returns a boolean indicating whether or not this InputStream supports mark() and reset().
int read(byte[] b, int offset, int length)
Reads at most length bytes from the Stream and stores them in byte array b starting at offset.
int read(byte[] b)
Reads bytes from the Stream and stores them in byte array b.
abstract int read()
Reads a single byte from this InputStream and returns the result as an int.
synchronized void reset()
Reset this InputStream to the last marked location.
long skip(long n)
Skips n number of bytes in this InputStream.
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.io.Closeable

Public Constructors

public InputStream ()

This constructor does nothing interesting. Provided for signature compatibility.

Public Methods

public int available ()

Returns a int representing then number of bytes that are available before this InputStream will block. This method always returns 0. Subclasses should override and indicate the correct number of bytes available.

Returns
  • the number of bytes available before blocking.
Throws
IOException If an error occurs in this InputStream.

public void close ()

Close the InputStream. Concrete implementations of this class should free any resources during close. This implementation does nothing.

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

public void mark (int readlimit)

Set a Mark position in this InputStream. The parameter readLimit indicates how many bytes can be read before a mark is invalidated. Sending reset() will reposition the Stream back to the marked position provided readLimit has not been surpassed.

This default implementation does nothing and concrete subclasses must provide their own implementations.

Parameters
readlimit the number of bytes to be able to read before invalidating the mark.

public boolean markSupported ()

Returns a boolean indicating whether or not this InputStream supports mark() and reset(). This class provides a default implementation which returns false.

Returns
  • true if mark() and reset() are supported, false otherwise.

public int read (byte[] b, int offset, int length)

Reads at most length bytes from the Stream and stores them in byte array b starting at offset. Answer the number of bytes actually read or -1 if no bytes were read and end of stream was encountered.

Parameters
b the byte array in which to store the read bytes.
offset the offset in b to store the read bytes.
length the maximum number of bytes to store in b.
Returns
  • the number of bytes actually read or -1 if end of stream.
Throws
IOException If the stream is already closed or another IOException occurs.

public int read (byte[] b)

Reads bytes from the Stream and stores them in byte array b. Answer the number of bytes actually read or -1 if no bytes were read and end of stream was encountered.

Parameters
b the byte array in which to store the read bytes.
Returns
  • the number of bytes actually read or -1 if end of stream.
Throws
IOException If the stream is already closed or another IOException occurs.

public abstract int read ()

Reads a single byte from this InputStream and returns the result as an int. The low-order byte is returned or -1 of the end of stream was encountered. This abstract implementation must be provided by concrete subclasses.

Returns
  • the byte read or -1 if end of stream.
Throws
IOException If the stream is already closed or another IOException occurs.

public synchronized void reset ()

Reset this InputStream to the last marked location. If the readlimit has been passed or no mark has been set, throw IOException. This implementation throws IOException and concrete subclasses should provide proper implementations.

Throws
IOException If the stream is already closed or another IOException occurs.

public long skip (long n)

Skips n number of bytes in this InputStream. Subsequent read()'s will not return these bytes unless reset() is used. This method may perform multiple reads to read n bytes. This default implementation reads n bytes into a temporary buffer. Concrete subclasses should provide their own implementation.

Parameters
n the number of bytes to skip.
Returns
  • the number of bytes actually skipped.
Throws
IOException If the stream is already closed or another IOException occurs.