org.mmbase.util.functions
Class Parameter

java.lang.Object
  org.mmbase.core.AbstractDescriptor
      org.mmbase.util.functions.Parameter

All Implemented Interfaces:

Cloneable, Descriptor, Serializable

Direct Known Subclasses:

Parameter.Wrapper, ReturnType

public class Parameter

extends AbstractDescriptor

implements Serializable

Each (function) argument is specified by a Parameter object. A Parameter contains a name and type (it does not contain a value). An array of this is returned by Function.getParameterDefinition(), and this same array is used to create new empty Parameters object (by Function.createParameters()), which can contain actual values for each Parameter.

Since:

MMBase-1.7

Version:

$Id: Parameter.java,v 1.30 2006/06/20 20:13:55 michiel Exp $

Author:

Daniel Ockeloen (MMFunctionParam), Michiel Meeuwissen

See Also:

Parameters, Serialized Form

Nested Class Summary

static class

Parameter.Wrapper A Parameter.Wrapper wraps one Parameter around a Parameter[] (then you can put it in a Parameter[]).

Field Summary

static Parameter	CLOUD
static Parameter	CORENODE
protected DataType	dataType The parameter's data type
static Parameter[]	EMPTY An empty Parameter array.
static Parameter	FIELD
static Parameter	LANGUAGE Parameter which might be needed in lots of Parameter definitions.
static Parameter	LOCALE
static Parameter	NODE 'system' parameter set for nodefunctions.
static Parameter	REQUEST
static Parameter	RESPONSE
static Parameter	USER

Fields inherited from class org.mmbase.core.AbstractDescriptor

description, guiName, key

Constructor Summary

Parameter(Parameter p, boolean required)
Copy-constructor, just to copy it with different requiredness

Parameter(Parameter p, Object defaultValue)
Copy-constructor, just to copy it with different defaultValue (which implies that it is not required now)

Parameter(String name, Class type)
Create a Parameter object

Parameter(String name, Class type, boolean required)
Create a Parameter object

Parameter(String name, Class type, Object defaultValue)
Create a Parameter object

Parameter(String name, DataType dataType)
Create a Parameter object

Parameter(String name, DataType dataType, boolean copy)
Create a Parameter object

Method Summary

protected Object	autoCast(Object value) Tries to 'cast' an object for use with this parameter.
void	checkType(Object value) Checks if the passed object is of the correct class (compatible with the type of this Parameter), and throws an IllegalArgumentException if it doesn't.
boolean	equals(Object o) Whether parameter equals to other parameter.
DataType	getDataType() Returns the data type of this parameter.
Object	getDefaultValue() Returns the default value of this parameter (derived from the datatype).
Class	getTypeAsClass() Returns the type of values that this parameter accepts.
int	hashCode()
boolean	isRequired() Returns whether the parameter requires a value.
void	setDefaultValue(Object defaultValue) Sets the default value of this parameter.
String	toString()

Methods inherited from class org.mmbase.core.AbstractDescriptor

clone, clone, getDefaultLocale, getDescription, getDescription, getGUIName, getGUIName, getLocalizedDescription, getLocalizedGUIName, getName, setDescription, setDescription, setGUIName, setGUIName, setLocalizedDescription, setLocalizedGUIName

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

LANGUAGE

public static final Parameter LANGUAGE

Parameter which might be needed in lots of Parameter definitions. These parameters are 'standard' parameters, which can be filled in by the system. E.g. the mmbase taglib uses these constants, and if it has a cloud ('mm:cloud is used'), then cloud-parameters are filled automaticly.

LOCALE

public static final Parameter LOCALE

USER

public static final Parameter USER

RESPONSE

public static final Parameter RESPONSE

REQUEST

public static final Parameter REQUEST

CLOUD

public static final Parameter CLOUD

NODE

public static final Parameter NODE

'system' parameter set for nodefunctions.

Since:

MMBaes-1.8

CORENODE

public static final Parameter CORENODE

FIELD

public static final Parameter FIELD

EMPTY

public static final Parameter[] EMPTY

An empty Parameter array.

dataType

protected DataType dataType

The parameter's data type

Since:

MMBase-1.8

Constructor Detail

Parameter

public Parameter(String name,
                 DataType dataType)

Create a Parameter object

Parameters:

name - the name of the parameter

dataType - the datatype of the parameter to copy

Since:

MMBase-1.8

Parameter

public Parameter(String name,
                 DataType dataType,
                 boolean copy)

Create a Parameter object

Parameters:

name - the name of the parameter

dataType - the datatype of the parameter to assign or copy

copy - if true, teh datatype is copied. if not, it is assigned directly, that is, changing condfiitons on the parameter changes the passed datatype instance.

Since:

MMBase-1.8

Parameter

public Parameter(String name,
                 Class type)

Create a Parameter object

Parameters:

name - the name of the parameter

type - the class of the parameter's possible value

Parameter

public Parameter(String name,
                 Class type,
                 boolean required)

Create a Parameter object

Parameters:

name - the name of the parameter

type - the class of the parameter's possible value

required - whether the parameter requires a value

Parameter

public Parameter(String name,
                 Class type,
                 Object defaultValue)

Create a Parameter object

Parameters:

name - the name of the parameter

type - the class of the parameter's possible value

defaultValue - the value to use if the parameter has no value set

Parameter

public Parameter(Parameter p,
                 boolean required)

Copy-constructor, just to copy it with different requiredness

Parameter

public Parameter(Parameter p,
                 Object defaultValue)

Copy-constructor, just to copy it with different defaultValue (which implies that it is not required now)

Method Detail

getDefaultValue

public Object getDefaultValue()

Returns the default value of this parameter (derived from the datatype).

Returns:

the default value

setDefaultValue

public void setDefaultValue(Object defaultValue)

Sets the default value of this parameter.

Parameters:

defaultValue - the default value

getDataType

public DataType getDataType()

Returns the data type of this parameter.

Returns:

the datatype

Since:

MMBase-1.8

getTypeAsClass

public Class getTypeAsClass()

Returns the type of values that this parameter accepts.

Returns:

the type as a Class

isRequired

public boolean isRequired()

Returns whether the parameter requires a value.

Returns:

true if a value is required

checkType

public void checkType(Object value)

Checks if the passed object is of the correct class (compatible with the type of this Parameter), and throws an IllegalArgumentException if it doesn't.

Parameters:

value - teh value whose type (class) to check

Throws:

IllegalArgumentException - if the type is not compatible

autoCast

protected Object autoCast(Object value)

Tries to 'cast' an object for use with this parameter. E.g. if value is a String, but this parameter is of type Integer, then the string can be parsed to Integer.

Parameters:

value - The value to be filled in in this Parameter.

hashCode

public int hashCode()

equals

public boolean equals(Object o)

Whether parameter equals to other parameter. Only key and type are consided. DefaultValue and required propererties are only 'utilities'.

Returns:

true if o is Parameter of which key and type equal to this' key and type.

toString

public String toString()

Overrides:

toString in class AbstractDescriptor