org.deepsymmetry.beatlink.dbserver

Class NumberField

java.lang.Object

org.deepsymmetry.beatlink.dbserver.Field

org.deepsymmetry.beatlink.dbserver.NumberField

public class NumberField
extends Field

A number field represents an integer, and can take up 1, 2, or 4 bytes, depending on the tag which introduces it.

Author:

James Elliott

Field Summary

Fields

Modifier and Type	Field and Description
static NumberField	WORD_0 A four-byte field representing the number zero, used in many requests, so they can save the time and garbage of constructing throwaway versions.
static NumberField	WORD_1 A four-byte field representing the number one, used in some requests, so they can save the time and garbage of constructing throwaway versions.

Constructor Summary

Constructors

Constructor and Description
NumberField(byte typeTag, DataInputStream is) Constructor for reading from the network.
NumberField(long value) Convenience constructor from code, for the most common case of wanting a 4-byte number field.
NumberField(long value, int size) Constructor from code.

Method Summary

Modifier and Type	Method and Description
byte	getArgumentTag() Get the value which identifies this type of field in a message argument list.
ByteBuffer	getBytes() Get the bytes which represent this field when sent over the network, including the leading type tag.
long	getSize() Get the size, in bytes, of the network representation of this field, excluding the leading type tag and length bytes (if any).
byte	getTypeTag() Get the value which identifies the start of this field in the network stream.
long	getValue() Get the numeric value this field represents.
String	toString()

Methods inherited from class org.deepsymmetry.beatlink.dbserver.Field

read, write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

WORD_0

public static final NumberField WORD_0

A four-byte field representing the number zero, used in many requests, so they can save the time and garbage of constructing throwaway versions.

WORD_1

public static final NumberField WORD_1

A four-byte field representing the number one, used in some requests, so they can save the time and garbage of constructing throwaway versions.

Constructor Detail

NumberField

public NumberField(byte typeTag,
                   DataInputStream is)
            throws IOException

Constructor for reading from the network.

Parameters:

typeTag - the tag which identified this field as a NumberField, and which allows us to determine the proper size.

is - the stream on which the field value is to be read.

Throws:

IllegalArgumentException - if tag is not a valid number field tag.

IOException - if there is a problem reading the value.

NumberField

public NumberField(long value,
                   int size)

Constructor from code.

Parameters:

value - the desired value to be represented by this field.

size - the number of bytes to be used to hold the value: 1, 2, or 4.

Throws:

IllegalArgumentException - if the specified size is not a supported number field size.

NumberField

public NumberField(long value)

Convenience constructor from code, for the most common case of wanting a 4-byte number field.

Parameters:

value - the desired value to be represented by this field.

Method Detail

getValue

public long getValue()

Get the numeric value this field represents.

Returns:

the number which this field contains.

getTypeTag

public byte getTypeTag()

Description copied from class: Field

Get the value which identifies the start of this field in the network stream.

Specified by:

getTypeTag in class Field

Returns:

the tag which tells the recipient that this particular type of field is coming.

getArgumentTag

public byte getArgumentTag()

Description copied from class: Field

Get the value which identifies this type of field in a message argument list.

Specified by:

getArgumentTag in class Field

Returns:

the tag which is used instead of the type tag for some reason when putting together the argument type list for a dbserver message.

getSize

public long getSize()

Description copied from class: Field

Get the size, in bytes, of the network representation of this field, excluding the leading type tag and length bytes (if any).

Specified by:

getSize in class Field

Returns:

the number of bytes which will be written after the type tag (and length indicator, if present) when sending this field.

getBytes

public ByteBuffer getBytes()

Description copied from class: Field

Get the bytes which represent this field when sent over the network, including the leading type tag.

Specified by:

getBytes in class Field

Returns:

a freshly rewound buffer containing the full set of bytes which should be transmitted for this field.

toString

public String toString()

Overrides:

toString in class Object