org.mmbase.bridge.implementation
Class BasicFunctionValue

java.lang.Object
  org.mmbase.bridge.implementation.BasicFunctionValue

All Implemented Interfaces:

FieldValue

public class BasicFunctionValue

extends java.lang.Object

implements FieldValue

This implementation of the Field Value interface is used by getFunctionValue of Node. This represents the result of a `function' on a node and it (therefore) is a unmodifiable.

Since:

MMBase-1.6

Version:

$Id: BasicFunctionValue.java,v 1.6 2004/01/14 21:51:15 michiel Exp $

Author:

Michiel Meeuwissen

Method Summary

boolean	canModify() Function values cannot be changed
java.lang.Object	get() Returns the value as an Object.
java.lang.Object	getField() Returns the Field object belonging to this value.
Node	getNode() Returns the Node to which this value belongs.
void	set(java.lang.Object value) Function values cannot be changed, and all set-functions throw an exception.
void	setBoolean(boolean value) Function values cannot be changed, and all set-functions throw an exception.
void	setByte(byte[] value) Function values cannot be changed, and all set-functions throw an exception.
void	setDouble(double value) Function values cannot be changed, and all set-functions throw an exception.
void	setFLoat(float value) Function values cannot be changed, and all set-functions throw an exception.
void	setInt(int value) Function values cannot be changed, and all set-functions throw an exception.
void	setLong(long value) Function values cannot be changed, and all set-functions throw an exception.
void	setNode(Node value) Function values cannot be changed, and all set-functions throw an exception.
void	setString(java.lang.String value) Function values cannot be changed, and all set-functions throw an exception.
void	setXML(org.w3c.dom.Document value) Function values cannot be changed, and all set-functions throw an exception.
boolean	toBoolean() Returns the value as an boolean (true or false).
byte[]	toByte() Returns the value as a byte array.
double	toDouble() Returns the value as a double.
float	toFloat() Returns the value as a float.
int	toInt() Returns the value as an int.
long	toLong() Returns the value as a long.
Node	toNode() Returns the value as a Node.
java.lang.String	toString() Returns the value as a String.
org.w3c.dom.Document	toXML() Returns the value as a org.w3c.dom.Document If the node value is not itself a Document, the method attempts to attempts to convert the String value into an XML.
org.w3c.dom.Element	toXML(org.w3c.dom.Document tree) Returns the value as a org.w3c.dom.Element If the node value is not itself a Document, the method attempts to attempts to convert the String value into an XML.

Methods inherited from class java.lang.Object

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

Method Detail

canModify

public boolean canModify()

Function values cannot be changed

Specified by:

canModify in interface FieldValue

Returns:

false

get

public java.lang.Object get()

Description copied from interface: FieldValue

Returns the value as an Object. The object type may vary and is dependent on how data was stored in a field. I.e. It may be possible for an Integer field to return it's value as a String if it was stored that way in the first place.

Specified by:

get in interface FieldValue

Returns:

the field value as an object

getField

public java.lang.Object getField()

Description copied from interface: FieldValue

Returns the Field object belonging to this value.

Specified by:

getField in interface FieldValue

Returns:

the field object

getNode

public Node getNode()

Description copied from interface: FieldValue

Returns the Node to which this value belongs.

Specified by:

getNode in interface FieldValue

Returns:

the Node object

toBoolean

public boolean toBoolean()

Description copied from interface: FieldValue

Returns the value as an boolean (true or false). If the actual value is a Boolean object, this call returns it's (primitive) boolean value. If the actual value is a Number object, this call returns true if the value is a positive, non-zero, value. In other words, values '0' and '-1' are concidered false. If the value is a string, this call returns true if the value is "true" or "yes" (case-insensitive). In all other cases (including calling byte fields), false is returned.

Specified by:

toBoolean in interface FieldValue

Returns:

the field value as a boolean

toByte

public byte[] toByte()

Description copied from interface: FieldValue

Returns the value as a byte array. This function returns either the value of a byte field, or the byte value of a string (converted using the default encoding, i.e. UTF8) Other types of values return an empty byte-array.

Specified by:

toByte in interface FieldValue

Returns:

the field value as a byte array

toFloat

public float toFloat()

Description copied from interface: FieldValue

Returns the value as a float. This function attempts to convert the value to a float. Numeric fields are simply converted. Boolean fields return 0.0 if false, and 1.0 if true. String fields are parsed. If a parsed string contains an error, ot the field value is not of a type that can be converted (i.e. a byte array), this function returns -1.0.

Specified by:

toFloat in interface FieldValue

Returns:

the field value as a float

toDouble

public double toDouble()

Description copied from interface: FieldValue

Returns the value as a double. This function attempts to convert the value to a double. Numeric fields are simply converted. Double may be truncated. Boolean fields return 0.0 if false, and 1.0 if true. String fields are parsed. If a parsed string contains an error, ot the field value is not of a type that can be converted (i.e. a byte array), this function returns -1.0.

Specified by:

toDouble in interface FieldValue

Returns:

the field value as a double

toLong

public long toLong()

Description copied from interface: FieldValue

Returns the value as a long. This function attempts to convert the value to a long. Numeric fields are simply converted. Double and float values may be truncated. Boolean fields return 0 if false, and 1 if true. String fields are parsed. If a parsed string contains an error, ot the field value is not of a type that can be converted (i.e. a byte array), this function returns -1

Specified by:

toLong in interface FieldValue

Returns:

the field value as a long.

toInt

public int toInt()

Description copied from interface: FieldValue

Returns the value as an int. This function attempts to convert the value to an int. Numeric fields are simply converted. Double and float values may be truncated. For Node values, the numeric key is returned. Long values return -1 of the value is too large. Boolean fields return 0 if false, and 1 if true. String fields are parsed. If a parsed string contains an error, ot the field value is not of a type that can be converted (i.e. a byte array), this function returns -1

Specified by:

toInt in interface FieldValue

Returns:

the field value as an int.

toNode

public Node toNode()

Description copied from interface: FieldValue

Returns the value as a Node. This function attempts to retrieve the node represented by the value. For numeric fields the node is retrieved using the numeric values as the node key. String fields are used as Node aliases, withw hich to retrieve the Node. If the node does not exist, or the value is of anotehr type, the function returns null.

Specified by:

toNode in interface FieldValue

Returns:

the field value as a Node

toString

public java.lang.String toString()

Description copied from interface: FieldValue

Returns the value as a String. Byte arrays are converted to string using the default encoding (UTF8). Node values return a string representation of their numeric key. DOM Documents are serialized to a proper strign represnattion fo the xml. For other values the result is calling the toString() method on the actual object.

Specified by:

toString in interface FieldValue

toXML

public org.w3c.dom.Document toXML()
                           throws java.lang.IllegalArgumentException

Description copied from interface: FieldValue

Returns the value as a org.w3c.dom.Document If the node value is not itself a Document, the method attempts to attempts to convert the String value into an XML. If the value cannot be converted, this method returns null

Specified by:

toXML in interface FieldValue

Returns:

the field value as a Document

Throws:

java.lang.IllegalArgumentException - if the Field is not of type TYPE_XML.

toXML

public org.w3c.dom.Element toXML(org.w3c.dom.Document tree)
                          throws java.lang.IllegalArgumentException

Description copied from interface: FieldValue

Returns the value as a org.w3c.dom.Element If the node value is not itself a Document, the method attempts to attempts to convert the String value into an XML. This method fails (throws a IllegalArgumentException) if the Field is not of type TYPE_XML. If the value cannot be converted, this method returns null

Specified by:

toXML in interface FieldValue

Parameters:

tree - the DOM Document to which the Element is added (as the document root element)

Returns:

the field value as an Element

Throws:

java.lang.IllegalArgumentException - if the Field is not of type TYPE_XML.

set

public void set(java.lang.Object value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

set in interface FieldValue

Parameters:

value - the field value as an Object

Throws:

BridgeException

See Also:

FieldValue.get()

setBoolean

public void setBoolean(boolean value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setBoolean in interface FieldValue

Parameters:

value - the field value as a boolean

Throws:

BridgeException

See Also:

FieldValue.toBoolean()

setFLoat

public void setFLoat(float value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setFLoat in interface FieldValue

Parameters:

value - the field value as a float

Throws:

BridgeException

See Also:

FieldValue.toFloat()

setDouble

public void setDouble(double value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setDouble in interface FieldValue

Parameters:

value - the field value as a double

Throws:

BridgeException

See Also:

FieldValue.toDouble()

setLong

public void setLong(long value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setLong in interface FieldValue

Parameters:

value - the field value as a long

Throws:

BridgeException

See Also:

FieldValue.toLong()

setInt

public void setInt(int value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setInt in interface FieldValue

Parameters:

value - the field value as a int

Throws:

BridgeException

See Also:

FieldValue.toInt()

setByte

public void setByte(byte[] value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setByte in interface FieldValue

Parameters:

value - the field value as a byte array

Throws:

BridgeException

See Also:

FieldValue.toByte()

setString

public void setString(java.lang.String value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setString in interface FieldValue

Parameters:

value - the field value as a String

Throws:

BridgeException

See Also:

FieldValue.toString()

setNode

public void setNode(Node value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setNode in interface FieldValue

Parameters:

value - the field value as a Node

Throws:

BridgeException

See Also:

FieldValue.toNode()

setXML

public void setXML(org.w3c.dom.Document value)

Function values cannot be changed, and all set-functions throw an exception.

Specified by:

setXML in interface FieldValue

Parameters:

value - the field value as a XML Document

Throws:

BridgeException

See Also:

FieldValue.toXML()