org.apache.commons.jelly.tags.core

Class UseBeanTag

java.lang.Object

org.apache.commons.jelly.TagSupport

org.apache.commons.jelly.DynaTagSupport

org.apache.commons.jelly.MapTagSupport

org.apache.commons.jelly.tags.core.UseBeanTag

All Implemented Interfaces:

DynaTag, BeanSource, Tag

Direct Known Subclasses:

UseListTag

public class UseBeanTag
extends MapTagSupport
implements BeanSource

A tag which instantiates an instance of the given class and then sets the properties on the bean. The class can be specified via a Class instance or a String which will be used to load the class using either the current thread's context class loader or the class loader used to load this Jelly library. This tag can be used it as follows,

 <j:useBean var="person" class="com.acme.Person" name="James" location="${loc}"/>
 <j:useBean var="order" class="${orderClass}" amount="12" price="123.456"/>
 

Version:

$Revision: 155420 $

Author:

James Strachan

Field Summary

Fields inherited from class org.apache.commons.jelly.TagSupport

body, context, parent

Constructor Summary

Constructors

Constructor and Description
UseBeanTag()
UseBeanTag(Class defaultClass)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addIgnoreProperty(String name) Adds a name to the Set of property names that will be skipped when setting bean properties.
protected Class	convertToClass(Object classObject) Attempts to convert the given object to a Class instance.
void	doTag(XMLOutput output) Evaluates this tag after all the tags properties have been initialized.
Object	getBean()
protected Class	getDefaultClass() Allows derived classes to provide a default bean implementation class
protected Set	getIgnorePropertySet()
boolean	isIgnoreUnknownProperties()
protected Class	loadClass(String className) Loads the given class using the default class loading mechanism which is to try use the current Thread's context class loader first otherise use the class loader which loaded this class.
protected Object	newInstance(Class theClass, Map attributes, XMLOutput output) Creates a new instance of the given class, which by default will invoke the default constructor.
protected void	processBean(String var, Object bean) By default this will export the bean using the given variable if it is defined.
protected void	setBean(Object bean) Allow derived classes to programatically set the bean
protected void	setBeanProperties(Object bean, Map attributes) Sets the properties on the bean.
void	setIgnoreUnknownProperties(boolean ignoreUnknownProps) If this tag finds an attribute in the XML that's not ignored by ignoreProperties and isn't a bean property, should it throw an exception?
protected void	validateBeanProperties(Object bean, Map attributes) If isIgnoreUnknownProperties() returns true, make sure that every non-ignored (addIgnoreProperty(String)) property matches a writable property on the target bean.

Methods inherited from class org.apache.commons.jelly.MapTagSupport

createAttributes, getAttributes, setAttribute

Methods inherited from class org.apache.commons.jelly.DynaTagSupport

getAttributeType

Methods inherited from class org.apache.commons.jelly.TagSupport

findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, findAncestorWithClass, getBody, getBodyText, getBodyText, getContext, getParent, invokeBody, isEscapeText, isTrim, setBody, setContext, setEscapeText, setParent, setTrim, trimBody

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.jelly.Tag

getBody, getContext, getParent, invokeBody, setBody, setContext, setParent

Constructor Detail

UseBeanTag

public UseBeanTag()

UseBeanTag

public UseBeanTag(Class defaultClass)

Method Detail

getBean

public Object getBean()

Specified by:

getBean in interface BeanSource

Returns:

the bean that has just been created

doTag

public void doTag(XMLOutput output)
           throws JellyTagException

Description copied from interface: Tag

Evaluates this tag after all the tags properties have been initialized.

Specified by:

doTag in interface Tag

Throws:

JellyTagException

setBean

protected void setBean(Object bean)

Allow derived classes to programatically set the bean

convertToClass

protected Class convertToClass(Object classObject)
                        throws MissingAttributeException,
                               ClassNotFoundException

Attempts to convert the given object to a Class instance. If the classObject is already a Class it will be returned otherwise it will be converted to a String and loaded using the default class loading mechanism.

Throws:

MissingAttributeException

ClassNotFoundException

loadClass

protected Class loadClass(String className)
                   throws ClassNotFoundException

Loads the given class using the default class loading mechanism which is to try use the current Thread's context class loader first otherise use the class loader which loaded this class.

Throws:

ClassNotFoundException

newInstance

protected Object newInstance(Class theClass,
                 Map attributes,
                 XMLOutput output)
                      throws JellyTagException

Creates a new instance of the given class, which by default will invoke the default constructor. Derived tags could do something different here.

Throws:

JellyTagException

setBeanProperties

protected void setBeanProperties(Object bean,
                     Map attributes)
                          throws JellyTagException

Sets the properties on the bean. Derived tags could implement some custom type conversion etc.

This method ignores all property names in the Set returned by getIgnorePropertySet().

Throws:

JellyTagException

validateBeanProperties

protected void validateBeanProperties(Object bean,
                          Map attributes)
                               throws JellyTagException

If isIgnoreUnknownProperties() returns true, make sure that every non-ignored (addIgnoreProperty(String)) property matches a writable property on the target bean.

Parameters:

bean - the bean to validate

attributes - the list of properties to validate

Throws:

JellyTagException - when a property is not writeable

processBean

protected void processBean(String var,
               Object bean)
                    throws JellyTagException

By default this will export the bean using the given variable if it is defined. This Strategy method allows derived tags to process the beans in different ways such as to register this bean with its parent tag etc.

Throws:

JellyTagException

getDefaultClass

protected Class getDefaultClass()

Allows derived classes to provide a default bean implementation class

addIgnoreProperty

protected void addIgnoreProperty(String name)

Adds a name to the Set of property names that will be skipped when setting bean properties. In other words, names added here won't be set into the bean if they're present in the attribute Map.

Parameters:

name -

getIgnorePropertySet

protected Set getIgnorePropertySet()

Returns:

the Set of property names that should be ignored when setting the properties of the bean.

isIgnoreUnknownProperties

public boolean isIgnoreUnknownProperties()

Returns:

See Also:

#setIgnoreUnknownProperties(boolean)}

setIgnoreUnknownProperties

public void setIgnoreUnknownProperties(boolean ignoreUnknownProps)

If this tag finds an attribute in the XML that's not ignored by ignoreProperties and isn't a bean property, should it throw an exception?

Parameters:

ignoreUnknownProperties - Sets ignoreUnknownProperties.