Class ByteArrayInputStream
- java.lang.Object
-
- java.io.InputStream
-
- java.io.ByteArrayInputStream
- All Implemented Interfaces:
-
Closeable
,AutoCloseable
public class ByteArrayInputStream extends InputStream
A ByteArrayInputStream
contains an internal buffer that contains bytes that may be read from the stream. An internal counter keeps track of the next byte to be supplied by the read
method.
Closing a ByteArrayInputStream
has no effect. The methods in this class can be called after the stream has been closed without generating an IOException
.
- Since:
- 1.0
- See Also:
StringBufferInputStream
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected byte[] | buf | An array of bytes that was provided by the creator of the stream. |
protected int | count | The index one greater than the last valid character in the input stream buffer. |
protected int | mark | The currently marked position in the stream. |
protected int | pos | The index of the next character to read from the input stream buffer. |
Constructor Summary
Constructor | Description |
---|---|
ByteArrayInputStream(byte[] buf) | Creates a |
ByteArrayInputStream(byte[] buf,
int offset,
int length) | Creates |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
int | available() | Returns the number of remaining bytes that can be read (or skipped over) from this input stream. |
void | close() | Closing a |
void | mark(int readAheadLimit) | Set the current marked position in the stream. |
boolean | markSupported() | Tests if this |
int | read() | Reads the next byte of data from this input stream. |
int | read(byte[] b,
int off,
int len) | Reads up to |
void | reset() | Resets the buffer to the marked position. |
long | skip(long n) | Skips |
Methods declared in class java.io.InputStream
nullInputStream, read, readAllBytes, readNBytes, readNBytes, transferTo
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Field Detail
buf
protected byte[] buf
An array of bytes that was provided by the creator of the stream. Elements buf[0]
through buf[count-1]
are the only bytes that can ever be read from the stream; element buf[pos]
is the next byte to be read.
pos
protected int pos
The index of the next character to read from the input stream buffer. This value should always be nonnegative and not larger than the value of count
. The next byte to be read from the input stream buffer will be buf[pos]
.
mark
protected int mark
The currently marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by the mark()
method. The current buffer position is set to this point by the reset()
method.
If no mark has been set, then the value of mark is the offset passed to the constructor (or 0 if the offset was not supplied).
- Since:
- 1.1
count
protected int count
The index one greater than the last valid character in the input stream buffer. This value should always be nonnegative and not larger than the length of buf
. It is one greater than the position of the last byte within buf
that can ever be read from the input stream buffer.
Constructor Detail
ByteArrayInputStream
public ByteArrayInputStream(byte[] buf)
Creates a ByteArrayInputStream
so that it uses buf
as its buffer array. The buffer array is not copied. The initial value of pos
is 0
and the initial value of count
is the length of buf
.
- Parameters:
-
buf
- the input buffer.
ByteArrayInputStream
public ByteArrayInputStream(byte[] buf, int offset, int length)
Creates ByteArrayInputStream
that uses buf
as its buffer array. The initial value of pos
is offset
and the initial value of count
is the minimum of offset+length
and buf.length
. The buffer array is not copied. The buffer's mark is set to the specified offset.
- Parameters:
-
buf
- the input buffer. -
offset
- the offset in the buffer of the first byte to read. -
length
- the maximum number of bytes to read from the buffer.
Method Detail
read
public int read()
Reads the next byte of data from this input stream. The value byte is returned as an int
in the range 0
to 255
. If no byte is available because the end of the stream has been reached, the value -1
is returned.
This read
method cannot block.
- Specified by:
-
read
in classInputStream
- Returns:
- the next byte of data, or
-1
if the end of the stream has been reached.
read
public int read(byte[] b, int off, int len)
Reads up to len
bytes of data into an array of bytes from this input stream. If pos
equals count
, then -1
is returned to indicate end of file. Otherwise, the number k
of bytes read is equal to the smaller of len
and count-pos
. If k
is positive, then bytes buf[pos]
through buf[pos+k-1]
are copied into b[off]
through b[off+k-1]
in the manner performed by System.arraycopy
. The value k
is added into pos
and k
is returned.
This read
method cannot block.
- Overrides:
-
read
in classInputStream
- Parameters:
-
b
- the buffer into which the data is read. -
off
- the start offset in the destination arrayb
-
len
- 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:
-
NullPointerException
- Ifb
isnull
. -
IndexOutOfBoundsException
- Ifoff
is negative,len
is negative, orlen
is greater thanb.length - off
- See Also:
InputStream.read()
skip
public long skip(long n)
Skips n
bytes of input from this input stream. Fewer bytes might be skipped if the end of the input stream is reached. The actual number k
of bytes to be skipped is equal to the smaller of n
and count-pos
. The value k
is added into pos
and k
is returned.
- Overrides:
-
skip
in classInputStream
- Parameters:
-
n
- the number of bytes to be skipped. - Returns:
- the actual number of bytes skipped.
available
public int available()
Returns the number of remaining bytes that can be read (or skipped over) from this input stream.
The value returned is count - pos
, which is the number of bytes remaining to be read from the input buffer.
- Overrides:
-
available
in classInputStream
- Returns:
- the number of remaining bytes that can be read (or skipped over) from this input stream without blocking.
markSupported
public boolean markSupported()
Tests if this InputStream
supports mark/reset. The markSupported
method of ByteArrayInputStream
always returns true
.
- Overrides:
-
markSupported
in classInputStream
- Returns:
-
true
if this stream instance supports the mark and reset methods;false
otherwise. - Since:
- 1.1
- See Also:
-
InputStream.mark(int)
,InputStream.reset()
mark
public void mark(int readAheadLimit)
Set the current marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by this method.
If no mark has been set, then the value of the mark is the offset passed to the constructor (or 0 if the offset was not supplied).
Note: The readAheadLimit
for this class has no meaning.
- Overrides:
-
mark
in classInputStream
- Parameters:
-
readAheadLimit
- the maximum limit of bytes that can be read before the mark position becomes invalid. - Since:
- 1.1
- See Also:
InputStream.reset()
reset
public void reset()
Resets the buffer to the marked position. The marked position is 0 unless another position was marked or an offset was specified in the constructor.
- Overrides:
-
reset
in classInputStream
- See Also:
-
InputStream.mark(int)
,IOException
close
public void close() throws IOException
Closing a ByteArrayInputStream
has no effect. The methods in this class can be called after the stream has been closed without generating an IOException
.
- Specified by:
-
close
in interfaceAutoCloseable
- Specified by:
-
close
in interfaceCloseable
- Overrides:
-
close
in classInputStream
- Throws:
-
IOException
- if an I/O error occurs.