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Java Fundamental Classes Reference

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The java.io Package
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DataInput

Name

DataInput

Synopsis

Interface Name:

java.io.DataInput

Super-interface:

None

Immediate Sub-interfaces:

java.io.ObjectInput

Implemented By:

java.io.DataInputStream, java.io.RandomAccessFile

Availability:

JDK 1.0 or later

Description

The DataInput interface defines methods for reading primitive data types and lines of text from an input stream in a machine-independent manner. All multibyte quantities are assumed to be in a format that stores the most significant byte as the first byte and the least significant byte as the last byte.

Interface Declaration

public abstract interface java.io.DataInput {
  // Methods
  public abstract boolean readBoolean();
  public abstract byte readByte();
  public abstract char readChar();
  public abstract double readDouble();
  public abstract float readFloat();
  public abstract void readFully(byte[] b);
  public abstract void readFully(byte[] b, int off, int len);
  public abstract int readInt();
  public abstract String readLine();
  public abstract long readLong();
  public abstract short readShort();
  public abstract int readUnsignedByte();
  public abstract int readUnsignedShort();
  public abstract String readUTF();
  public abstract int skipBytes(int n);
}

Methods

readBoolean

public abstract boolean readBoolean() throws IOException

Returns

The boolean value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a byte as a boolean value. A byte that contains a zero is read as false; that which contains a nonzero is read as true.

readByte

public abstract byte readByte() throws IOException

Returns

The byte value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a signed 8-bit byte.

readChar

public abstract char readChar() throws IOException

Returns

The char value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 16-bit char.

readDouble

public abstract double readDouble() throws IOException

Returns

The double value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 64-bit double quantity.

readFloat

public abstract float readFloat() throws IOException

Returns

The float value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 32-bit float quantity.

readFully

public abstract void readFully(byte[] b) throws IOException

Parameters

b

The array to fill.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads bytes into the given array b until the array is full.

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

Parameters

b

The array to fill.

off

An offset into the array.

len

The number of bytes to read.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads len bytes into the given array, starting at offset off.

readInt

public abstract int readInt() throws IOException

Returns

The int value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 32-bit int quantity.

readLine

public abstract String readLine() throws IOException

Returns

A String that contains the line read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a String from the current position through the next line terminator. Implementations of this method should take care to look for any line terminator: "\n", "\r", or "\r\n".

readLong

public abstract long readLong() throws IOException

Returns

The long value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 64-bit long quantity.

readShort

public abstract short readShort() throws IOException

Returns

The short value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 16-bit short quantity.

readUnsignedByte

public abstract int readUnsignedByte() throws IOException

Returns

The unsigned byte value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads an 8-bit byte as an unsigned quantity.

readUnsignedShort

public abstract int readUnsignedShort() throws IOException

Returns

The unsigned short value read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method reads a 16-bit short as an unsigned quantity.

readUTF

public abstract String readUTF() throws IOException

Returns

The String read from the stream.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

UTFDataFormatException

If the bytes do not represent a valid UTF-8 encoding.

Description

This method reads a UTF-8 format String. See Appendix B, The UTF-8 Encoding, for information on the UTF-8 encoding.

skipBytes

public abstract int skipBytes(int n) throws IOException

Parameters

n

The number of bytes to skip.

Returns

The actual number of skipped bytes.

Throws

EOFException

If the end of the file is encountered.

IOException

If any other kind of I/O error occurs.

Description

This method skips over n bytes.

See Also

DataInputStream, EOFException, IOException, ObjectInput, RandomAccessFile, UTFDataFormatException


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