java.io.DataOutput Maven / Gradle / Ivy

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This work corresponds to the API signatures of JSR 219: Foundation Profile 1.1. In the event of a discrepency between this work and the JSR 219 specification, which is available at http://www.jcp.org/en/jsr/detail?id=219, the latter takes precedence. */ package java.io; /** * The 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 Java 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 * @version 1.13, 02/02/00 * @see java.io.DataInput * @see java.io.DataOutputStream * @since JDK1.0 */ 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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:

*

     * (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. * @exception IOException if an I/O error occurs. */ public void writeShort(int v) throws IOException; /** * Writes a char value, wich * is comprised of two bytes, to the * output stream. * The byte values to be written, in the order * shown, are: *

     * (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. * @exception IOException if an I/O error occurs. */ public 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: *

     * (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. * @exception IOException if an I/O error occurs. */ public 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: *

     * (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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public 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. * @exception IOException if an I/O error occurs. */ public void writeChars(String s) throws IOException; /** * Writes two bytes of length information * to the output stream, followed * by the Java modified UTF 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:

     * (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:

     * (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.