java.io
Class DataOutputStream

java.lang.Object
  |
  +--java.io.OutputStream
        |
        +--java.io.DataOutputStream

All Implemented Interfaces:

DataOutput

public class DataOutputStream

extends OutputStream

implements DataOutput

A data output stream lets an application write primitive Java data types to an output stream in a portable way. An application can then use a data input stream to read the data back in.

Since:

JDK1.0, CLDC 1.0

See Also:

DataInputStream

Field Summary

protected OutputStream

out The output stream.

Constructor Summary

DataOutputStream(OutputStream out)
Creates a new data output stream to write data to the specified underlying output stream.

Method Summary

void	close() Closes this output stream and releases any system resources associated with the stream.
void	flush() Flushes this data output stream.
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to the underlying output stream.
void	write(int b) Writes the specified byte (the low eight bits of the argument b) to the underlying output stream.
void	writeBoolean(boolean v) Writes a boolean to the underlying output stream as a 1-byte value.
void	writeByte(int v) Writes out a byte to the underlying output stream as a 1-byte value.
void	writeChar(int v) Writes a char to the underlying output stream as a 2-byte value, high byte first.
void	writeChars(String s) Writes a string to the underlying output stream as a sequence of characters.
void	writeDouble(double v) Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the underlying output stream as an 8-byte quantity, high byte first.
void	writeFloat(float v) Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the underlying output stream as a 4-byte quantity, high byte first.
void	writeInt(int v) Writes an int to the underlying output stream as four bytes, high byte first.
void	writeLong(long v) Writes a long to the underlying output stream as eight bytes, high byte first.
void	writeShort(int v) Writes a short to the underlying output stream as two bytes, high byte first.
void	writeUTF(String str) Writes a string to the underlying output stream using UTF-8 encoding in a machine-independent manner.

Methods inherited from class java.io.OutputStream

write

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.io.DataOutput

write

Field Detail

out

protected OutputStream out

The output stream.

Constructor Detail

DataOutputStream

public DataOutputStream(OutputStream out)

Creates a new data output stream to write data to the specified underlying output stream.

Parameters:

out - the underlying output stream, to be saved for later use.

Method Detail

write

public void write(int b)
           throws IOException

Writes the specified byte (the low eight bits of the argument b) to the underlying output stream.

Implements the write method of OutputStream.

Specified by:

write in interface DataOutput

Specified by:

write in class OutputStream

Parameters:

b - the byte to be written.

Throws:

IOException - if an I/O error occurs.

write

public void write(byte[] b,
                  int off,
                  int len)
           throws IOException

Writes len bytes from the specified byte array starting at offset off to the underlying output stream.

Specified by:

write in interface DataOutput

Overrides:

write in class OutputStream

Parameters:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

IOException - if an I/O error occurs.

flush

public void flush()
           throws IOException

Flushes this data output stream. This forces any buffered output bytes to be written out to the stream.

The flush method of DataOutputStream calls the flush method of its underlying output stream.

Overrides:

flush in class OutputStream

Throws:

IOException - if an I/O error occurs.

close

public void close()
           throws IOException

Closes this output stream and releases any system resources associated with the stream.

The close method calls its flush method, and then calls the close method of its underlying output stream.

Overrides:

close in class OutputStream

Throws:

IOException - if an I/O error occurs.

writeBoolean

public final void writeBoolean(boolean v)
                        throws IOException

Writes a boolean to the underlying output stream as a 1-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0.

Specified by:

writeBoolean in interface DataOutput

Parameters:

v - a boolean value to be written.

Throws:

IOException - if an I/O error occurs.

writeByte

public final void writeByte(int v)
                     throws IOException

Writes out a byte to the underlying output stream as a 1-byte value.

Specified by:

writeByte in interface DataOutput

Parameters:

v - a byte value to be written.

Throws:

IOException - if an I/O error occurs.

writeShort

public final void writeShort(int v)
                      throws IOException

Writes a short to the underlying output stream as two bytes, high byte first.

Specified by:

writeShort in interface DataOutput

Parameters:

v - a short to be written.

Throws:

IOException - if an I/O error occurs.

writeChar

public final void writeChar(int v)
                     throws IOException

Writes a char to the underlying output stream as a 2-byte value, high byte first.

Specified by:

writeChar in interface DataOutput

Parameters:

v - a char value to be written.

Throws:

IOException - if an I/O error occurs.

writeInt

public final void writeInt(int v)
                    throws IOException

Writes an int to the underlying output stream as four bytes, high byte first.

Specified by:

writeInt in interface DataOutput

Parameters:

v - an int to be written.

Throws:

IOException - if an I/O error occurs.

writeLong

public final void writeLong(long v)
                     throws IOException

Writes a long to the underlying output stream as eight bytes, high byte first.

Specified by:

writeLong in interface DataOutput

Parameters:

v - a long to be written.

Throws:

IOException - if an I/O error occurs.

writeFloat

public final void writeFloat(float v)
                      throws IOException

Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the underlying output stream as a 4-byte quantity, high byte first.

Specified by:

writeFloat in interface DataOutput

Parameters:

v - a float value to be written.

Throws:

IOException - if an I/O error occurs.

Since:

CLDC 1.1

See Also:

Float.floatToIntBits(float)

writeDouble

public final void writeDouble(double v)
                       throws IOException

Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the underlying output stream as an 8-byte quantity, high byte first.

Specified by:

writeDouble in interface DataOutput

Parameters:

v - a double value to be written.

Throws:

IOException - if an I/O error occurs.

Since:

CLDC 1.1

See Also:

Double.doubleToLongBits(double)

writeChars

public final void writeChars(String s)
                      throws IOException

Writes a string to the underlying output stream as a sequence of characters. Each character is written to the data output stream as if by the writeChar method.

Specified by:

writeChars in interface DataOutput

Parameters:

s - a String value to be written.

Throws:

IOException - if an I/O error occurs.

See Also:

writeChar(int)

writeUTF

public final void writeUTF(String str)
                    throws IOException

Writes a string to the underlying output stream using UTF-8 encoding in a machine-independent manner.

First, two bytes are written to the output stream as if by the writeShort method giving the number of bytes to follow. This value is the number of bytes actually written out, not the length of the string. Following the length, each character of the string is output, in sequence, using the UTF-8 encoding for the character.

Specified by:

writeUTF in interface DataOutput

Parameters:

str - a string to be written.

Throws:

IOException - if an I/O error occurs.