DataOutput interface provides
* for converting data from any of the Java
* primitive types to a series of bytes and
* writing these bytes to a binary stream.
* There is also a facility for converting
* a String into
* modified UTF-8
* format and writing the resulting series
* of bytes.
*
* For all the methods in this interface that
* write bytes, it is generally true that if
* a byte cannot be written for any reason,
* an IOException is thrown.
*
* @author Frank Yellin
* @see java.io.DataInput
* @see java.io.DataOutputStream
* @since 1.0
*/
public
interface DataOutput {
/**
* Writes to the output stream the eight
* low-order bits of the argument b.
* The 24 high-order bits of b
* are ignored.
*
* @param b the byte to be written.
* @throws IOException if an I/O error occurs.
*/
void write(int b) throws IOException;
/**
* Writes to the output stream all the bytes in array b.
* If b is null,
* a NullPointerException is thrown.
* If b.length is zero, then
* no bytes are written. Otherwise, the byte
* b[0] is written first, then
* b[1], and so on; the last byte
* written is b[b.length-1].
*
* @param b the data.
* @throws IOException if an I/O error occurs.
*/
void write(byte[] b) throws IOException;
/**
* Writes len bytes from array
* b, in order, to
* the output stream. If b
* is null, a NullPointerException
* is thrown. If off is negative,
* or len is negative, or off+len
* is greater than the length of the array
* b, then an IndexOutOfBoundsException
* is thrown. If len is zero,
* then no bytes are written. Otherwise, the
* byte b[off] is written first,
* then b[off+1], and so on; the
* last byte written is b[off+len-1].
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @throws IOException if an I/O error occurs.
*/
void write(byte[] b, int off, int len) throws IOException;
/**
* Writes a boolean value to this output stream.
* If the argument v
* is true, the value (byte)1
* is written; if v is false,
* the value (byte)0 is written.
* The byte written by this method may
* be read by the readBoolean
* method of interface DataInput,
* which will then return a boolean
* equal to v.
*
* @param v the boolean to be written.
* @throws IOException if an I/O error occurs.
*/
void writeBoolean(boolean v) throws IOException;
/**
* Writes to the output stream the eight low-
* order bits of the argument v.
* The 24 high-order bits of v
* are ignored. (This means that writeByte
* does exactly the same thing as write
* for an integer argument.) The byte written
* by this method may be read by the readByte
* method of interface DataInput,
* which will then return a byte
* equal to (byte)v.
*
* @param v the byte value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeByte(int v) throws IOException;
/**
* Writes two bytes to the output
* stream to represent the value of the argument.
* The byte values to be written, in the order
* shown, are:
*
{@code
* (byte)(0xff & (v >> 8))
* (byte)(0xff & v)
* }
* The bytes written by this method may be
* read by the readShort method
* of interface DataInput , which
* will then return a short equal
* to (short)v.
*
* @param v the short value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeShort(int v) throws IOException;
/**
* Writes a char value, which
* is comprised of two bytes, to the
* output stream.
* The byte values to be written, in the order
* shown, are:
*
{@code
* (byte)(0xff & (v >> 8))
* (byte)(0xff & v)
* }
* The bytes written by this method may be
* read by the readChar method
* of interface DataInput , which
* will then return a char equal
* to (char)v.
*
* @param v the char value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeChar(int v) throws IOException;
/**
* Writes an int value, which is
* comprised of four bytes, to the output stream.
* The byte values to be written, in the order
* shown, are:
*
{@code
* (byte)(0xff & (v >> 24))
* (byte)(0xff & (v >> 16))
* (byte)(0xff & (v >> 8))
* (byte)(0xff & v)
* }
* The bytes written by this method may be read
* by the readInt method of interface
* DataInput , which will then
* return an int equal to v.
*
* @param v the int value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeInt(int v) throws IOException;
/**
* Writes a long value, which is
* comprised of eight bytes, to the output stream.
* The byte values to be written, in the order
* shown, are:
*
{@code
* (byte)(0xff & (v >> 56))
* (byte)(0xff & (v >> 48))
* (byte)(0xff & (v >> 40))
* (byte)(0xff & (v >> 32))
* (byte)(0xff & (v >> 24))
* (byte)(0xff & (v >> 16))
* (byte)(0xff & (v >> 8))
* (byte)(0xff & v)
* }
* The bytes written by this method may be
* read by the readLong method
* of interface DataInput , which
* will then return a long equal
* to v.
*
* @param v the long value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeLong(long v) throws IOException;
/**
* Writes a float value,
* which is comprised of four bytes, to the output stream.
* It does this as if it first converts this
* float value to an int
* in exactly the manner of the Float.floatToIntBits
* method and then writes the int
* value in exactly the manner of the writeInt
* method. The bytes written by this method
* may be read by the readFloat
* method of interface DataInput,
* which will then return a float
* equal to v.
*
* @param v the float value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeFloat(float v) throws IOException;
/**
* Writes a double value,
* which is comprised of eight bytes, to the output stream.
* It does this as if it first converts this
* double value to a long
* in exactly the manner of the Double.doubleToLongBits
* method and then writes the long
* value in exactly the manner of the writeLong
* method. The bytes written by this method
* may be read by the readDouble
* method of interface DataInput,
* which will then return a double
* equal to v.
*
* @param v the double value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeDouble(double v) throws IOException;
/**
* Writes a string to the output stream.
* For every character in the string
* s, taken in order, one byte
* is written to the output stream. If
* s is null, a NullPointerException
* is thrown.
If s.length
* is zero, then no bytes are written. Otherwise,
* the character s[0] is written
* first, then s[1], and so on;
* the last character written is s[s.length-1].
* For each character, one byte is written,
* the low-order byte, in exactly the manner
* of the writeByte method . The
* high-order eight bits of each character
* in the string are ignored.
*
* @param s the string of bytes to be written.
* @throws IOException if an I/O error occurs.
*/
void writeBytes(String s) throws IOException;
/**
* Writes every character in the string s,
* to the output stream, in order,
* two bytes per character. If s
* is null, a NullPointerException
* is thrown. If s.length
* is zero, then no characters are written.
* Otherwise, the character s[0]
* is written first, then s[1],
* and so on; the last character written is
* s[s.length-1]. For each character,
* two bytes are actually written, high-order
* byte first, in exactly the manner of the
* writeChar method.
*
* @param s the string value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeChars(String s) throws IOException;
/**
* Writes two bytes of length information
* to the output stream, followed
* by the
* modified UTF-8
* representation
* of every character in the string s.
* If s is null,
* a NullPointerException is thrown.
* Each character in the string s
* is converted to a group of one, two, or
* three bytes, depending on the value of the
* character.
* If a character c
* is in the range \u0001 through
* \u007f, it is represented
* by one byte:
*
(byte)c
* If a character c is \u0000
* or is in the range \u0080
* through \u07ff, then it is
* represented by two bytes, to be written
* in the order shown:
{@code
* (byte)(0xc0 | (0x1f & (c >> 6)))
* (byte)(0x80 | (0x3f & c))
* } If a character
* c is in the range \u0800
* through uffff, then it is
* represented by three bytes, to be written
* in the order shown:
{@code
* (byte)(0xe0 | (0x0f & (c >> 12)))
* (byte)(0x80 | (0x3f & (c >> 6)))
* (byte)(0x80 | (0x3f & c))
* } First,
* the total number of bytes needed to represent
* all the characters of s is
* calculated. If this number is larger than
* 65535, then a UTFDataFormatException
* is thrown. Otherwise, this length is written
* to the output stream in exactly the manner
* of the writeShort method;
* after this, the one-, two-, or three-byte
* representation of each character in the
* string s is written.
The
* bytes written by this method may be read
* by the readUTF method of interface
* DataInput , which will then
* return a String equal to s.
*
* @param s the string value to be written.
* @throws IOException if an I/O error occurs.
*/
void writeUTF(String s) throws IOException;
}