org.apache.commons.beanutils.expression

Interface Resolver

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:

Since: 1.8.0

Version: $Revision: 555845 $ $Date: 2007-07-13 03:52:05 +0100 (Fri, 13 Jul 2007) $

See Also: setResolver

Method Summary
intgetIndex(String expression)
Extract the index value from the property expression or -1.
StringgetKey(String expression)
Extract the map key from the property expression or null.
StringgetProperty(String expression)
Return the property name from the property expression.
booleanhasNested(String expression)
Indicates whether or not the expression contains nested property expressions or not.
booleanisIndexed(String expression)
Indicate whether the expression is for an indexed property or not.
booleanisMapped(String expression)
Indicate whether the expression is for a mapped property or not.
Stringnext(String expression)
Extract the next property expression from the current expression.
Stringremove(String expression)
Remove the last property expresson from the current expression.

Method Detail

getIndex

public 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

public 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

public String getProperty(String expression)
Return the property name from the property expression.

Parameters: expression The property expression

Returns: The property name

hasNested

public 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

public 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

public 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

public String next(String expression)
Extract the next property expression from the current expression.

Parameters: expression The property expression

Returns: The next property expression

remove

public 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

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