org.apache.commons.beanutils.expression

Interface Resolver

All Known Implementing Classes:

DefaultResolver

public interface Resolver

Property Name Expression Resolver.

Methods such as PropertyUtilsBean's setNestedProperty() method use a Resolver to process a property name expression and resolve nested, indexed and mapped property names. The following code provides an example usage demonstrating all the methods:

      // Iterate through a nested property expression
      while (resolver.hasNested(name)) {

          // isolate a single property from a nested expresion
          String next = resolver.next(name);

          // Process...
          String property = resolver.getProperty(next);
          if (resolver.isIndexed(next)) {

              int index = resolver.getIndex(next);
              bean = getIndexedProperty(bean, property, index);

          } else if (resolver.isMapped(next)) {

              String key = resolver.getKey(next);
              bean = getMappedProperty(bean, property, key);

          } else {

              bean = getSimpleProperty(bean, property);

          }

          // remove the processed property from the expression
          name = resolver.remove(name);
      }
 

In order to create an implementation, it is important to understand how BeanUtils/PropertyUtils uses the resolver. The following are the main methods that use it:

• PropertyUtilsBean
• PropertyUtilsBean.getIndexedProperty(Object, String)
• PropertyUtilsBean.getMappedProperty(Object, String)
• PropertyUtilsBean.getNestedProperty(Object, String)
• PropertyUtilsBean.getPropertyDescriptor(Object, String)
• PropertyUtilsBean.getSimpleProperty(Object, String)
• PropertyUtilsBean.setIndexedProperty(Object, String, Object)
• PropertyUtilsBean.setMappedProperty(Object, String, Object)
• PropertyUtilsBean.setNestedProperty(Object, String, Object)
• PropertyUtilsBean.setSimpleProperty(Object, String, Object)
• BeanUtilsBean
• BeanUtilsBean.copyProperty(Object, String, Object)
• BeanUtilsBean.setProperty(Object, String, Object)
• LocaleBeanUtilsBean
• LocaleBeanUtilsBean.setProperty(Object, String, Object, String)

Since:

1.8.0

Version:

$Id$

See Also:

PropertyUtilsBean.setResolver(Resolver)

Method Summary

Modifier and Type	Method and Description
int	getIndex(String expression) Extract the index value from the property expression or -1.
String	getKey(String expression) Extract the map key from the property expression or null.
String	getProperty(String expression) Return the property name from the property expression.
boolean	hasNested(String expression) Indicates whether or not the expression contains nested property expressions or not.
boolean	isIndexed(String expression) Indicate whether the expression is for an indexed property or not.
boolean	isMapped(String expression) Indicate whether the expression is for a mapped property or not.
String	next(String expression) Extract the next property expression from the current expression.
String	remove(String expression) Remove the last property expresson from the current expression.

Method Detail

getIndex

int getIndex(String expression)

Extract the index value from the property expression or -1.

Parameters:

expression - The property expression

Returns:

The index value or -1 if the property is not indexed

Throws:

IllegalArgumentException - If the indexed property is illegally formed or has an invalid (non-numeric) value

getKey

String getKey(String expression)

Extract the map key from the property expression or null.

Parameters:

expression - The property expression

Returns:

The index value

Throws:

IllegalArgumentException - If the mapped property is illegally formed

getProperty

String getProperty(String expression)

Return the property name from the property expression.

Parameters:

expression - The property expression

Returns:

The property name

hasNested

boolean hasNested(String expression)

Indicates whether or not the expression contains nested property expressions or not.

Parameters:

expression - The property expression

Returns:

The next property expression

isIndexed

boolean isIndexed(String expression)

Indicate whether the expression is for an indexed property or not.

Parameters:

expression - The property expression

Returns:

true if the expresion is indexed, otherwise false

isMapped

boolean isMapped(String expression)

Indicate whether the expression is for a mapped property or not.

Parameters:

expression - The property expression

Returns:

true if the expresion is mapped, otherwise false

next

String next(String expression)

Extract the next property expression from the current expression.

Parameters:

expression - The property expression

Returns:

The next property expression

remove

String remove(String expression)

Remove the last property expresson from the current expression.

Parameters:

expression - The property expression

Returns:

The new expression value, with first property expression removed - null if there are no more expressions