DataInput

Members

Functions

readBoolean

bool readBoolean()

Reads one input byte and returns {@code true} if that byte is nonzero, {@code false} if that byte is zero. This method is suitable for reading the byte written by the {@code writeBoolean} method of interface {@code DataOutput}.

readByte

byte readByte()

Reads and returns one input byte. The byte is treated as a signed value in the range {@code -128} through {@code 127}, inclusive. This method is suitable for reading the byte written by the {@code writeByte} method of interface {@code DataOutput}.

readChar

char readChar()

Reads two input bytes and returns a {@code char} value. Let {@code a} be the first byte read and {@code b} be the second byte. The value returned is: <pre>{@code (char)((a << 8) | (b & 0xff)) }</pre> This method is suitable for reading bytes written by the {@code writeChar} method of interface {@code DataOutput}.

readDouble

double readDouble()

Reads eight input bytes and returns a {@code double} value. It does this by first constructing a {@code long} value in exactly the manner of the {@code readLong} method, then converting this {@code long} value to a {@code double} in exactly the manner of the method {@code Double.longBitsToDouble}. This method is suitable for reading bytes written by the {@code writeDouble} method of interface {@code DataOutput}.

readFloat

float readFloat()

Reads four input bytes and returns a {@code float} value. It does this by first constructing an {@code int} value in exactly the manner of the {@code readInt} method, then converting this {@code int} value to a {@code float} in exactly the manner of the method {@code Float.intBitsToFloat}. This method is suitable for reading bytes written by the {@code writeFloat} method of interface {@code DataOutput}.

readFully

void readFully(byte[] b)

Reads some bytes from an input stream and stores them into the buffer array {@code b}. The number of bytes read is equal to the length of {@code b}. <p> This method blocks until one of the following conditions occurs: <ul> <li>{@code b.length} bytes of input data are available, in which case a normal return is made.

readFully

void readFully(byte[] b, int off, int len)

Reads {@code len} bytes from an input stream. <p> This method blocks until one of the following conditions occurs: <ul> <li>{@code len} bytes of input data are available, in which case a normal return is made.

readInt

int readInt()

Reads four input bytes and returns an {@code int} value. Let {@code a-d} be the first through fourth bytes read. The value returned is: <pre>{@code (((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff)) }</pre> This method is suitable for reading bytes written by the {@code writeInt} method of interface {@code DataOutput}.

readLine

string readLine()

Reads the next line of text from the input stream. It reads successive bytes, converting each byte separately into a character, until it encounters a line terminator or end of file; the characters read are then returned as a {@code string}. Note that because this method processes bytes, it does not support input of the full Unicode character set. <p> If end of file is encountered before even one byte can be read, then {@code null} is returned. Otherwise, each byte that is read is converted to type {@code char} by zero-extension. If the character {@code '\n'} is encountered, it is discarded and reading ceases. If the character {@code '\r'} is encountered, it is discarded and, if the following byte converts &#32;to the character {@code '\n'}, then that is discarded also; reading then ceases. If end of file is encountered before either of the characters {@code '\n'} and {@code '\r'} is encountered, reading ceases. Once reading has ceased, a {@code string} is returned that contains all the characters read and not discarded, taken in order. Note that every character in this string will have a value less than {@code \u005Cu0100}, that is, {@code (char)256}.

readLong

long readLong()

Reads eight input bytes and returns a {@code long} value. Let {@code a-h} be the first through eighth bytes read. The value returned is: <pre>{@code (((long)(a & 0xff) << 56) | ((long)(b & 0xff) << 48) | ((long)(c & 0xff) << 40) | ((long)(d & 0xff) << 32) | ((long)(e & 0xff) << 24) | ((long)(f & 0xff) << 16) | ((long)(g & 0xff) << 8) | ((long)(h & 0xff))) }</pre> <p> This method is suitable for reading bytes written by the {@code writeLong} method of interface {@code DataOutput}.

readShort

short readShort()

Reads two input bytes and returns a {@code short} value. Let {@code a} be the first byte read and {@code b} be the second byte. The value returned is: <pre>{@code (short)((a << 8) | (b & 0xff)) }</pre> This method is suitable for reading the bytes written by the {@code writeShort} method of interface {@code DataOutput}.

readUTF

string readUTF()

Reads in a string that has been encoded using a <a href="#modified-utf-8">modified UTF-8</a> format. The general contract of {@code readUTF} is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a {@code string}. <p> First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the {@code readUnsignedShort} method . This integer value is called the <i>UTF length</i> and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group. <p> If the first byte of a group matches the bit pattern {@code 0xxxxxxx} (where {@code x} means "may be {@code 0} or {@code 1}"), then the group consists of just that byte. The byte is zero-extended to form a character. <p> If the first byte of a group matches the bit pattern {@code 110xxxxx}, then the group consists of that byte {@code a} and a second byte {@code b}. If there is no byte {@code b} (because byte {@code a} was the last of the bytes to be read), or if byte {@code b} does not match the bit pattern {@code 10xxxxxx}, then a {@code UTFDataFormatException} is thrown. Otherwise, the group is converted to the character: <pre>{@code (char)(((a & 0x1F) << 6) | (b & 0x3F)) }</pre> If the first byte of a group matches the bit pattern {@code 1110xxxx}, then the group consists of that byte {@code a} and two more bytes {@code b} and {@code c}. If there is no byte {@code c} (because byte {@code a} was one of the last two of the bytes to be read), or either byte {@code b} or byte {@code c} does not match the bit pattern {@code 10xxxxxx}, then a {@code UTFDataFormatException} is thrown. Otherwise, the group is converted to the character: <pre>{@code (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F)) }</pre> If the first byte of a group matches the pattern {@code 1111xxxx} or the pattern {@code 10xxxxxx}, then a {@code UTFDataFormatException} is thrown. <p> If end of file is encountered at any time during this entire process, then an {@code EOFException} is thrown. <p> After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a {@code string}, which is returned. <p> The {@code writeUTF} method of interface {@code DataOutput} may be used to write data that is suitable for reading by this method. @return a Unicode string. @exception EOFException if this stream reaches the end before reading all the bytes. @exception IOException if an I/O error occurs. @exception UTFDataFormatException if the bytes do not represent a valid modified UTF-8 encoding of a string.

readUnsignedByte

int readUnsignedByte()

Reads one input byte, zero-extends it to type {@code int}, and returns the result, which is therefore in the range {@code 0} through {@code 255}. This method is suitable for reading the byte written by the {@code writeByte} method of interface {@code DataOutput} if the argument to {@code writeByte} was intended to be a value in the range {@code 0} through {@code 255}.

readUnsignedShort

int readUnsignedShort()

Reads two input bytes and returns an {@code int} value in the range {@code 0} through {@code 65535}. Let {@code a} be the first byte read and {@code b} be the second byte. The value returned is: <pre>{@code (((a & 0xff) << 8) | (b & 0xff)) }</pre> This method is suitable for reading the bytes written by the {@code writeShort} method of interface {@code DataOutput} if the argument to {@code writeShort} was intended to be a value in the range {@code 0} through {@code 65535}.

skipBytes

int skipBytes(int n)

Makes an attempt to skip over {@code n} bytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before {@code n} bytes have been skipped is only one possibility. This method never throws an {@code EOFException}. The actual number of bytes skipped is returned.

• DataInput