java.io
Class DataInputStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          java.io.DataInputStream

All Implemented Interfaces:

Closeable, DataInput

public class DataInputStream
extends FilterInputStream
implements DataInput

DataInputStream is a filter class which can read typed data from a Stream. Typically, this stream has been written by a DataOutputStream. Types that can be read include byte, 16-bit short, 32-bit int, 32-bit float, 64-bit long, 64-bit double, byte strings, and UTF Strings.

See Also:

DataOutputStream

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

DataInputStream(InputStream in)
Constructs a new DataInputStream on the InputStream in.

Method Summary

(package private) String	decodeUTF(int utfSize)
int	read(byte[] buffer) Reads bytes from the source stream into the byte array buffer.
int	read(byte[] buffer, int offset, int length) Read at most length bytes from this DataInputStream and stores them in byte array buffer starting at offset.
boolean	readBoolean() Reads a boolean from this stream.
byte	readByte() Reads an 8-bit byte value from this stream.
char	readChar() Reads a 16-bit character value from this stream.
double	readDouble() Reads a 64-bit double value from this stream.
float	readFloat() Reads a 32-bit float value from this stream.
void	readFully(byte[] buffer) Reads bytes from this stream into the byte array buffer.
void	readFully(byte[] buffer, int offset, int length) Reads bytes from this stream and stores them in the byte array buffer starting at the position offset.
int	readInt() Reads a 32-bit integer value from this stream.
String	readLine() Deprecated. Use BufferedReader
long	readLong() Reads a 64-bit long value from this stream.
short	readShort() Reads a 16-bit short value from this stream.
int	readUnsignedByte() Reads an unsigned 8-bit byte value from this stream and returns it as an int.
int	readUnsignedShort() Reads a 16-bit unsigned short value from this stream and returns it as an int.
String	readUTF() Reads a UTF format String from this Stream.
static String	readUTF(DataInput in) Reads a UTF format String from the DataInput Stream in.
int	skipBytes(int count) Skips count number of bytes in this stream.

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DataInputStream

public DataInputStream(InputStream in)

Constructs a new DataInputStream on the InputStream in. All reads can now be filtered through this stream. Note that data read by this Stream is not in a human readable format and was most likely created by a DataOutputStream.

Parameters:

in - the target InputStream to filter reads on.

See Also:

DataOutputStream, RandomAccessFile

Method Detail

read

public final int read(byte[] buffer)
               throws IOException

Reads bytes from the source stream into the byte array buffer. The number of bytes actually read is returned.

Overrides:

read in class FilterInputStream

Parameters:

buffer - the buffer to read bytes into

Returns:

the number of bytes actually read or -1 if end of stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.write(byte[]), DataOutput.write(byte[], int, int)

read

public final int read(byte[] buffer,
                      int offset,
                      int length)
               throws IOException

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

Overrides:

read in class FilterInputStream

Parameters:

buffer - the byte array in which to store the read bytes.

offset - the offset in buffer to store the read bytes.

length - the maximum number of bytes to store in buffer.

Returns:

the number of bytes actually read or -1 if end of stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.write(byte[]), DataOutput.write(byte[], int, int)

readBoolean

public final boolean readBoolean()
                          throws IOException

Reads a boolean from this stream.

Specified by:

readBoolean in interface DataInput

Returns:

the next boolean value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeBoolean(boolean)

readByte

public final byte readByte()
                    throws IOException

Reads an 8-bit byte value from this stream.

Specified by:

readByte in interface DataInput

Returns:

the next byte value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeByte(int)

readChar

public final char readChar()
                    throws IOException

Reads a 16-bit character value from this stream.

Specified by:

readChar in interface DataInput

Returns:

the next char value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeChar(int)

readDouble

public final double readDouble()
                        throws IOException

Reads a 64-bit double value from this stream.

Specified by:

readDouble in interface DataInput

Returns:

the next double value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeDouble(double)

readFloat

public final float readFloat()
                      throws IOException

Reads a 32-bit float value from this stream.

Specified by:

readFloat in interface DataInput

Returns:

the next float value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeFloat(float)

readFully

public final void readFully(byte[] buffer)
                     throws IOException

Reads bytes from this stream into the byte array buffer. This method will block until buffer.length number of bytes have been read.

Specified by:

readFully in interface DataInput

Parameters:

buffer - to read bytes into

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.write(byte[]), DataOutput.write(byte[], int, int)

readFully

public final void readFully(byte[] buffer,
                            int offset,
                            int length)
                     throws IOException

Reads bytes from this stream and stores them in the byte array buffer starting at the position offset. This method blocks until count bytes have been read.

Specified by:

readFully in interface DataInput

Parameters:

buffer - the byte array into which the data is read

offset - the offset the operation start at

length - the maximum number of bytes to read

Throws:

IOException - if a problem occurs while reading from this stream

EOFException - if reaches the end of the stream before enough bytes have been read

See Also:

DataInput.readFully(byte[], int, int)

readInt

public final int readInt()
                  throws IOException

Reads a 32-bit integer value from this stream.

Specified by:

readInt in interface DataInput

Returns:

the next int value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeInt(int)

readLine

@Deprecated
public final String readLine()
                      throws IOException

Deprecated. Use BufferedReader

Returns a String representing the next line of text available in this BufferedReader. A line is represented by 0 or more characters followed by '\n', '\r', "\n\r" or end of stream. The String does not include the newline sequence.

Specified by:

readLine in interface DataInput

Returns:

the contents of the line or null if no characters were read before end of stream.

Throws:

IOException - If the DataInputStream is already closed or some other IO error occurs.

readLong

public final long readLong()
                    throws IOException

Reads a 64-bit long value from this stream.

Specified by:

readLong in interface DataInput

Returns:

the next long value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeLong(long)

readShort

public final short readShort()
                      throws IOException

Reads a 16-bit short value from this stream.

Specified by:

readShort in interface DataInput

Returns:

the next short value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeShort(int)

readUnsignedByte

public final int readUnsignedByte()
                           throws IOException

Reads an unsigned 8-bit byte value from this stream and returns it as an int.

Specified by:

readUnsignedByte in interface DataInput

Returns:

the next unsigned byte value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeByte(int)

readUnsignedShort

public final int readUnsignedShort()
                            throws IOException

Reads a 16-bit unsigned short value from this stream and returns it as an int.

Specified by:

readUnsignedShort in interface DataInput

Returns:

the next unsigned short value from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeShort(int)

readUTF

public final String readUTF()
                     throws IOException

Reads a UTF format String from this Stream.

Specified by:

readUTF in interface DataInput

Returns:

the next UTF String from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeUTF(java.lang.String)

decodeUTF

String decodeUTF(int utfSize)
           throws IOException

Throws:

IOException

readUTF

public static final String readUTF(DataInput in)
                            throws IOException

Reads a UTF format String from the DataInput Stream in.

Parameters:

in - the input stream to read from

Returns:

the next UTF String from the source stream.

Throws:

IOException - If a problem occurs reading from this DataInputStream.

See Also:

DataOutput.writeUTF(java.lang.String)

skipBytes

public final int skipBytes(int count)
                    throws IOException

Skips count number of bytes in this stream. Subsequent read()'s will not return these bytes unless reset() is used.

Specified by:

skipBytes in interface DataInput

Parameters:

count - 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.