CheckedInputStream - JRE Emulation | JRE Emulation
public class

CheckedInputStream

extends FilterInputStream
java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FilterInputStream
       ↳ java.util.zip.CheckedInputStream

Class Overview

The CheckedInputStream class is used to maintain a checksum at the same time as the data, on which the checksum is computed, is read from a stream. The purpose of this checksum is to establish data integrity, comparing the computed checksum against a published checksum value.

Summary

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Inherited Fields
From class java.io.FilterInputStream
Public Constructors
CheckedInputStream(InputStream is, Checksum csum)
Constructs a new CheckedInputStream on InputStream is.
Public Methods
Checksum getChecksum()
Returns the checksum calculated on the stream read so far.
int read()
Reads one byte of data from the underlying input stream and updates the checksum with the byte data.
int read(byte[] buffer, int byteOffset, int byteCount)
Reads up to byteCount bytes of data from the underlying input stream, storing it into buffer, starting at offset byteOffset.
long skip(long byteCount)
Skip up to byteCount bytes of data on the underlying input stream.
Inherited Methods
[Expand]
From class java.io.FilterInputStream
From class java.io.InputStream
From class java.lang.Object
From interface java.io.Closeable
From interface java.lang.AutoCloseable

Public Constructors

public CheckedInputStream (InputStream is, Checksum csum)

Constructs a new CheckedInputStream on InputStream is. The checksum will be calculated using the algorithm implemented by csum.

Warning: passing a null source creates an invalid CheckedInputStream. All operations on such a stream will fail.

Parameters
is the input stream to calculate checksum from.
csum an entity implementing the checksum algorithm.

Public Methods

public Checksum getChecksum ()

Returns the checksum calculated on the stream read so far.

public int read ()

Reads one byte of data from the underlying input stream and updates the checksum with the byte data.

Returns
  • -1 at the end of the stream, a single byte value otherwise.
Throws
IOException if an IOException occurs.

public int read (byte[] buffer, int byteOffset, int byteCount)

Reads up to byteCount bytes of data from the underlying input stream, storing it into buffer, starting at offset byteOffset. The checksum is updated with the bytes read. Returns the number of bytes actually read or -1 if arrived at the end of the filtered stream while reading the data.

Parameters
buffer the buffer into which the data is read.
byteOffset the start offset in the destination array b
byteCount the maximum number of bytes read.
Returns
  • the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
Throws
IOException if this stream is closed or some I/O error occurs.

public long skip (long byteCount)

Skip up to byteCount bytes of data on the underlying input stream. Any skipped bytes are added to the running checksum value.

Parameters
byteCount the number of bytes to skip.
Returns
  • the number of bytes skipped.
Throws
IOException if this stream is closed or another I/O error occurs.