com.arsdigita.util.parameter
Class AbstractParameter

java.lang.Object
  com.arsdigita.util.parameter.AbstractParameter

All Implemented Interfaces:

Parameter

Direct Known Subclasses:

BooleanParameter, ClassParameter, EnumerationParameter, FileParameter, IntegerParameter, MapParameter, StringParameter

public abstract class AbstractParameter

extends Object

implements Parameter

Subject to change. A base implementation of the Parameter interface. It offers subclasses use of the Apache BeanUtils framework, should they opt to use it. Methods of the form doXXX are extension points for subclasses. The isRequired() and getDefaultValue() methods may also be overriden.

Version:

$Id: //core-platform/dev/src/com/arsdigita/util/parameter/AbstractParameter.java#8 $

Author:

Justin Ross <jross@redhat.com>

See Also:

Parameter

Field Summary

static String

versionId

Fields inherited from interface com.arsdigita.util.parameter.Parameter

OPTIONAL, REQUIRED

Constructor Summary

protected	AbstractParameter(String name, Class type) Constructs a new parameter using the beanutils converter for type type.
protected	AbstractParameter(String name, int multiplicity, Object defaalt) Constructs a new parameter with the default value defaalt.
protected	AbstractParameter(String name, int multiplicity, Object defaalt, Class type) Constructs a new parameter with the default value defaalt and using the beanutils converter registered for type.

Method Summary

protected Object	doRead(ParameterReader reader, ErrorList errors) Reads the value of the parameter from reader, unmarshals it, and returns it.
protected void	doValidate(Object value, ErrorList errors) Validates value, placing any validation errors in errors.
protected void	doWrite(ParameterWriter writer, Object value) Marshals and writes value to writer.
Object	getDefaultValue() Parameter users may override this method to achieve dynamic defaulting.
ParameterInfo	getInfo() Gets metadata associated with the parameter if it is available.
String	getName() Gets the name of the parameter.
boolean	isRequired() Parameter users may override this method to make the multiplicity of the parameter dependent on the multiplicity of related parameters.
protected String	marshal(Object value) Converts value to a representative String, which is returned.
Object	read(ParameterReader reader, ErrorList errors) Calls doRead(ParameterReader,ErrorList).
void	setInfo(ParameterInfo info) Sets the optional parameter metadata to info.
String	toString() Returns a String representation of this object.
protected Object	unmarshal(String value, ErrorList errors) Converts a literal String value, value, to a Java object, which is returned.
void	validate(Object value, ErrorList errors) Calls doValidate(Object,ErrorList) if value is not null.
void	write(ParameterWriter writer, Object value) Calls doWrite(ParameterWriter,Object).

Methods inherited from class java.lang.Object

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

Field Detail

versionId

public static final String versionId

See Also:

Constant Field Values

Constructor Detail

AbstractParameter

protected AbstractParameter(String name,
                            int multiplicity,
                            Object defaalt,
                            Class type)

Constructs a new parameter with the default value defaalt and using the beanutils converter registered for type.

Parameters:

name - The name of the parameter; it cannot be null

multiplicity - The multiplicity type of the parameter

defaalt - The default value to use if the value is unset or is null

type - The Class whose beanutils converter will be used to unmarshal literal values

AbstractParameter

protected AbstractParameter(String name,
                            int multiplicity,
                            Object defaalt)

Constructs a new parameter with the default value defaalt.

Parameters:

name - The name of the parameter; it cannot be null

multiplicity - The multiplicity type of the parameter

defaalt - The default value to use if the value is unset or is null

AbstractParameter

protected AbstractParameter(String name,
                            Class type)

Constructs a new parameter using the beanutils converter for type type. By default, the parameter is required and has no default.

Parameters:

name - The name of the parameter; it cannot be null

type - The Class whose beanutils converter will be used to unmarshal literal values

Method Detail

isRequired

public boolean isRequired()

Parameter users may override this method to make the multiplicity of the parameter dependent on the multiplicity of related parameters.

Specified by:

isRequired in interface Parameter

Returns:

true if the parameter cannot be null; false if it can be null

See Also:

Parameter.isRequired()

getName

public final String getName()

Description copied from interface: Parameter

Gets the name of the parameter.

Specified by:

getName in interface Parameter

Returns:

The String parameter name; it cannot be null

See Also:

Parameter.getName()

getDefaultValue

public Object getDefaultValue()

Parameter users may override this method to achieve dynamic defaulting.

Specified by:

getDefaultValue in interface Parameter

Returns:

The fallback value; it may be null

See Also:

Parameter.getDefaultValue()

getInfo

public final ParameterInfo getInfo()

Description copied from interface: Parameter

Gets metadata associated with the parameter if it is available.

Specified by:

getInfo in interface Parameter

Returns:

The ParameterInfo object; it may be null

See Also:

Parameter.getInfo()

setInfo

public final void setInfo(ParameterInfo info)

Description copied from interface: Parameter

Sets the optional parameter metadata to info.

Specified by:

setInfo in interface Parameter

Parameters:

info - The ParameterInfo to associate; it may be null

See Also:

Parameter.setInfo(ParameterInfo)

read

public final Object read(ParameterReader reader,
                         ErrorList errors)

Calls doRead(ParameterReader,ErrorList).

Specified by:

read in interface Parameter

Parameters:

reader - The ParameterReader from which to recover a string literal value; it cannot be null

errors - The ErrorList in which to collect any errors encountered; it cannot be null

Returns:

The Java object value of the parameter

See Also:

Parameter.read(ParameterReader,ErrorList)

doRead

protected Object doRead(ParameterReader reader,
                        ErrorList errors)

Reads the value of the parameter from reader, unmarshals it, and returns it. If any errors are encountered, they are added to errors. If the literal string value from reader is not null, this method delegates to unmarshal(String,ErrorList). This implementation is suited to a parameter with a singular scalar value. Subclasses that are compound parameters should override this method to delegate to child parameters.

Parameters:

reader - The ParameterReader that will supply the literal stored value for this parameter; it cannot be null

errors - The ErrorList that will trap any errors encountered; it cannot be null

unmarshal

protected Object unmarshal(String value,
                           ErrorList errors)

Converts a literal String value, value, to a Java object, which is returned.

Parameters:

value - The String value to convert from; it cannot be null

errors - An ErrorList that holds any errors encountered during unmarshaling; it cannot be null

validate

public final void validate(Object value,
                           ErrorList errors)

Calls doValidate(Object,ErrorList) if value is not null. Otherwise, if the value is required and null, an error is added to errors and doValidate is not called.

Specified by:

validate in interface Parameter

Parameters:

value - The value to validate; this is typically the value returned by Parameter.read(com.arsdigita.util.parameter.ParameterReader, com.arsdigita.util.parameter.ErrorList); it may be null

errors - The ErrorList in which to collect any errors encountered; it cannot be null

See Also:

Parameter.validate(Object,ErrorList)

doValidate

protected void doValidate(Object value,
                          ErrorList errors)

Validates value, placing any validation errors in errors. This particular implementation does nothing. Subclasses are expected to add specific validation behaviors.

Parameters:

value - The value to validate; it cannot be null

errors - The ErrorList that traps validation errors; it cannot be null

write

public final void write(ParameterWriter writer,
                        Object value)

Calls doWrite(ParameterWriter,Object).

Specified by:

write in interface Parameter

Parameters:

writer - The ParameterWriter that will take the marshaled value and store it; it cannot be null

value - The Java object value of the parameter

See Also:

Parameter.write(ParameterWriter,Object)

doWrite

protected void doWrite(ParameterWriter writer,
                       Object value)

Marshals and writes value to writer. This implementation is suited to a parameter with a singular scalar value. Subclasses that are compound parameters should override this method to delegate to child parameters.

Parameters:

writer - The ParameterWriter we write to; it cannot be null

value - The value to write; it may be null

marshal

protected String marshal(Object value)

Converts value to a representative String, which is returned.

Parameters:

value - The value to marshal; it may be null

Returns:

The String literal representation of value; it may be null

toString

public String toString()

Returns a String representation of this object.

Returns:

super.toString() + "," + getName() + "," + isRequired()