org.mmbase.bridge
Interface FieldValue

All Known Implementing Classes:

AbstractFieldValue, BasicFieldValue, BasicFunctionValue

public interface FieldValue

This interface represents a value stored in a node.

Since:

MMBase 1.6

Version:

$Id: FieldValue.java 34936 2009-05-04 14:41:51Z michiel $

Author:

Pierre van Rooden

Method Summary

boolean	canModify() Returns whether this value can be changed.
Object	get() Returns the value as an Object.
Field	getField() Returns the Field object belonging to this value.
Node	getNode() Returns the Node to which this value belongs.
boolean	isNull()
void	set(Object value) Sets the value, passing any Object The object type may vary and is generally stored in memory as-is, which means that, generally, the get() method returns the same object.
void	setBoolean(boolean value) Sets the value, passing a boolean value.
void	setByte(byte[] value) Sets the value, passing a byte array.
void	setDate(Date value) Sets the value, passing a java.util.Date object.
void	setDouble(double value) Sets the value, passing a double value.
void	setFLoat(float value) Sets the value, passing a float value.
void	setInt(int value) Sets the value, passing a int value.
void	setLong(long value) Sets the value, passing a long value.
void	setNode(Node value) Sets the value, passing a Node.
void	setObject(Object value)
void	setString(String value) Sets the value, passing a String.
void	setXML(Document value) Sets the value, passing a org.w3c.dom.Document object.
boolean	toBoolean() Returns the value as an boolean (true or false).
byte[]	toByte() Returns the value as a byte array.
Date	toDate() Returns the value as a java.util.Date If the value cannot be converted, this method returns null
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.
String	toString() Returns the value as a String.
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.
Element	toXML(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.

Method Detail

canModify

boolean canModify()

Returns whether this value can be changed. Some field values (such as the values of the number, owner, and otype fields) cannot be changed through this interface (but some may be changed through other means).

Returns:

true if the value can be changed

isNull

boolean isNull()

get

Object get()

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.

Returns:

the field value as an object

getField

Field getField()

Returns the Field object belonging to this value.

Returns:

the field object. Why not return Field?

getNode

Node getNode()

Returns the Node to which this value belongs.

Returns:

the Node object

toBoolean

boolean toBoolean()

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.

Returns:

the field value as a boolean

toByte

byte[] toByte()

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.

Returns:

the field value as a byte array

toFloat

float toFloat()

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.

Returns:

the field value as a float

toDouble

double toDouble()

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.

Returns:

the field value as a double

toLong

long toLong()

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

Returns:

the field value as a long.

toInt

int toInt()

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

Returns:

the field value as an int.

toNode

Node toNode()

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.

Returns:

the field value as a Node

toString

String toString()

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.

Overrides:

toString in class Object

Returns:

the field value as a String

toXML

Document toXML()
               throws IllegalArgumentException

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

Returns:

the field value as a Document

Throws:

IllegalArgumentException - if the Field is not of type TYPE_XML.

toDate

Date toDate()

Returns the value as a java.util.Date If the value cannot be converted, this method returns null

Returns:

the field value as Date

Since:

MMBase-1.8

toXML

Element toXML(Document tree)
              throws IllegalArgumentException

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

Parameters:

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

Returns:

the field value as an Element

Throws:

IllegalArgumentException - if the Field is not of type TYPE_XML.

set

void set(Object value)

Sets the value, passing any Object The object type may vary and is generally stored in memory as-is, which means that, generally, the get() method returns the same object. Note that for an XML field String values are converted to a XML document, and individual builders may make their own changes. The object is converted to the actual type (using the getXXX() methods detailed above) once the node is stored, though that does not affect the data in-memory until the Node is read anew from the storage. Note that this behavior may change in the future and therefor code should not be dependent on this. By preference, use the more specific methods for setting data (i.e. setString()).

Parameters:

value - the field value as an Object

See Also:

get()

setObject

void setObject(Object value)

setBoolean

void setBoolean(boolean value)

Sets the value, passing a boolean value. This value is converted to a Boolean object.

Parameters:

value - the field value as a boolean

See Also:

toBoolean()

setFLoat

void setFLoat(float value)

Sets the value, passing a float value. This value is converted to a Float object.

Parameters:

value - the field value as a float

See Also:

toFloat()

setDouble

void setDouble(double value)

Sets the value, passing a double value. This value is converted to a Double object.

Parameters:

value - the field value as a double

See Also:

toDouble()

setLong

void setLong(long value)

Sets the value, passing a long value. This value is converted to a Long object.

Parameters:

value - the field value as a long

See Also:

toLong()

setInt

void setInt(int value)

Sets the value, passing a int value. This value is converted to a Integer object.

Parameters:

value - the field value as a int

See Also:

toInt()

setByte

void setByte(byte[] value)

Sets the value, passing a byte array.

Parameters:

value - the field value as a byte array

See Also:

toByte()

setString

void setString(String value)

Sets the value, passing a String.

Parameters:

value - the field value as a String

See Also:

toString()

setNode

void setNode(Node value)

Sets the value, passing a Node.

Parameters:

value - the field value as a Node

See Also:

toNode()

setXML

void setXML(Document value)

Sets the value, passing a org.w3c.dom.Document object.

Parameters:

value - the field value as a XML Document

See Also:

toXML(org.w3c.dom.Document)

setDate

void setDate(Date value)

Sets the value, passing a java.util.Date object.

Parameters:

value - the field value as a java.util.Date Document

Since:

MMBase-1.8

See Also:

toDate()