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java.lang.Objectjava.io.InputStream
java.io.DataInputStream
@TransactionType(value=NOT_SUPPORTED) public class DataInputStream
A data input stream lets an application read primitive Java data types from an underlying input stream in a machine-independent way. An application uses a data output stream to write data that can later be read by a data input stream.
DataOutputStream
Field Summary | |
---|---|
protected InputStream |
in
The input stream. |
Constructor Summary | |
---|---|
DataInputStream(InputStream in)
Creates a DataInputStream and saves its argument, the
input stream in , for later use. |
Method Summary | |
---|---|
int |
available()
Returns the number of bytes that can be read from this input stream without blocking. |
void |
close()
Closes this input stream and releases any system resources associated with the stream. |
void |
mark(int readlimit)
Marks the current position in this input stream. |
boolean |
markSupported()
Tests if this input stream supports the mark and
reset methods. |
int |
read()
Reads the next byte of data from this input stream. |
int |
read(byte[] b)
See the general contract of the read method of
DataInput . |
int |
read(byte[] b,
int off,
int len)
Reads up to len bytes of data from this input stream into
an array of bytes. |
boolean |
readBoolean()
See the general contract of the readBoolean method of
DataInput . |
byte |
readByte()
See the general contract of the readByte method of
DataInput . |
char |
readChar()
See the general contract of the readChar method of
DataInput . |
void |
readFully(byte[] b)
See the general contract of the readFully method of
DataInput . |
void |
readFully(byte[] b,
int off,
int len)
See the general contract of the readFully method of
DataInput . |
int |
readInt()
See the general contract of the readInt method of
DataInput . |
long |
readLong()
See the general contract of the readLong method of
DataInput . |
short |
readShort()
See the general contract of the readShort method of
DataInput . |
int |
readUnsignedByte()
See the general contract of the readUnsignedByte method of
DataInput . |
int |
readUnsignedShort()
See the general contract of the readUnsignedShort method
of DataInput . |
String |
readUTF()
See the general contract of the readUTF method of
DataInput . |
static String |
readUTF(DataInput in)
Reads from the stream in a representation of a Unicode
character string encoded in Java modified UTF-8 format; this string of
characters is then returned as a String . |
void |
reset()
Repositions this stream to the position at the time the mark
method was last called on this input stream. |
long |
skip(long n)
Skips over and discards n bytes of data from the input
stream. |
int |
skipBytes(int n)
See the general contract of the skipBytes method of
DataInput . |
Methods inherited from class java.lang.Object |
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equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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protected InputStream in
Constructor Detail |
---|
public DataInputStream(InputStream in)
DataInputStream
and saves its argument, the
input stream in
, for later use.
in
- the input stream.Method Detail |
---|
public int read() throws IOException
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
method blocks until input data is available, the end of the stream is
detected, or an exception is thrown.
This method simply performs in.read()
and returns the
result.
read
in class InputStream
-1
if the end of the
stream is reached.
IOException
- if an I/O error occurs.public final int read(byte[] b) throws IOException
read
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
read
in class InputStream
b
- the buffer into which the data is read.
-1
if there is no more data because the end of the
stream has been reached.
IOException
- if an I/O error occurs.InputStream.read(byte[], int, int)
public final int read(byte[] b, int off, int len) throws IOException
len
bytes of data from this input stream into
an array of bytes. This method blocks until some input is available.
This method simply performs in.read(b, off, len)
and
returns the result.
read
in class InputStream
b
- the buffer into which the data is read.off
- the start offset of the data.len
- the maximum number of bytes read.
-1
if there is no more data because the end of the
stream has been reached.
IOException
- if an I/O error occurs.InputStream.read()
public final void readFully(byte[] b) throws IOException
readFully
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readFully
in interface DataInput
b
- the buffer into which the data is read.
EOFException
- if this input stream reaches the end before reading all
the bytes.
IOException
- if an I/O error occurs.public final void readFully(byte[] b, int off, int len) throws IOException
readFully
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readFully
in interface DataInput
b
- the buffer into which the data is read.off
- the start offset of the data.len
- the number of bytes to read.
EOFException
- if this input stream reaches the end before reading all
the bytes.
IOException
- if an I/O error occurs.public final int skipBytes(int n) throws IOException
skipBytes
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
skipBytes
in interface DataInput
n
- the number of bytes to be skipped.
IOException
- if an I/O error occurs.public final boolean readBoolean() throws IOException
readBoolean
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readBoolean
in interface DataInput
boolean
value read.
EOFException
- if this input stream has reached the end.
IOException
- if an I/O error occurs.public final byte readByte() throws IOException
readByte
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readByte
in interface DataInput
byte
.
EOFException
- if this input stream has reached the end.
IOException
- if an I/O error occurs.public final int readUnsignedByte() throws IOException
readUnsignedByte
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readUnsignedByte
in interface DataInput
EOFException
- if this input stream has reached the end.
IOException
- if an I/O error occurs.public final short readShort() throws IOException
readShort
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readShort
in interface DataInput
EOFException
- if this input stream reaches the end before reading two
bytes.
IOException
- if an I/O error occurs.public final int readUnsignedShort() throws IOException
readUnsignedShort
method
of DataInput
.
Bytes for this operation are read from the contained input stream.
readUnsignedShort
in interface DataInput
EOFException
- if this input stream reaches the end before reading two
bytes.
IOException
- if an I/O error occurs.public final char readChar() throws IOException
readChar
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readChar
in interface DataInput
EOFException
- if this input stream reaches the end before reading two
bytes.
IOException
- if an I/O error occurs.public final int readInt() throws IOException
readInt
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readInt
in interface DataInput
int
.
EOFException
- if this input stream reaches the end before reading four
bytes.
IOException
- if an I/O error occurs.public final long readLong() throws IOException
readLong
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readLong
in interface DataInput
long
.
EOFException
- if this input stream reaches the end before reading eight
bytes.
IOException
- if an I/O error occurs.public final String readUTF() throws IOException
readUTF
method of
DataInput
.
Bytes for this operation are read from the contained input stream.
readUTF
in interface DataInput
EOFException
- if this input stream reaches the end before reading all
the bytes.
IOException
- if an I/O error occurs.readUTF(java.io.DataInput)
public static final String readUTF(DataInput in) throws IOException
in
a representation of a Unicode
character string encoded in Java modified UTF-8 format; this string of
characters is then returned as a String
. The details of
the modified UTF-8 representation are exactly the same as for the
readUTF
method of DataInput
.
in
- a data input stream.
EOFException
- if the input stream reaches the end before all the bytes.
IOException
- if an I/O error occurs.
UTFDataFormatException
- if the bytes do not represent a valid UTF-8 encoding of a
Unicode string.readUnsignedShort()
public long skip(long n) throws IOException
n
bytes of data from the input
stream. The skip
method may, for a variety of reasons, end
up skipping over some smaller number of bytes, possibly 0
.
The actual number of bytes skipped is returned.
This method simply performs in.skip(n)
.
skip
in class InputStream
n
- the number of bytes to be skipped.
IOException
- if an I/O error occurs.public int available() throws IOException
This method simply performs in.available()
and returns the
result.
available
in class InputStream
IOException
- if an I/O error occurs.public void close() throws IOException
in.close()
.
close
in class InputStream
IOException
- if an I/O error occurs.public void mark(int readlimit)
reset
method repositions this stream at the last marked
position so that subsequent reads re-read the same bytes.
The readlimit
argument tells this input stream to allow
that many bytes to be read before the mark position gets invalidated.
This method simply performs in.mark(readlimit)
.
mark
in class InputStream
readlimit
- the maximum limit of bytes that can be read before the mark
position becomes invalid.InputStream.reset()
public void reset() throws IOException
mark
method was last called on this input stream.
This method simply performs in.reset()
.
Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.
reset
in class InputStream
IOException
- if the stream has not been marked or if the mark has been
invalidated.InputStream.mark(int)
,
IOException
public boolean markSupported()
mark
and
reset
methods. This method simply performs
in.markSupported()
.
markSupported
in class InputStream
true
if this stream type supports the
mark
and reset
method;
false
otherwise.InputStream.mark(int)
,
InputStream.reset()
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