Package org.apache.commons.beanutils

Class FluentPropertyBeanIntrospector

  • All Implemented Interfaces:
    BeanIntrospector
    public class FluentPropertyBeanIntrospector
extends java.lang.Object
implements BeanIntrospector

    An implementation of the BeanIntrospector interface which can detect write methods for properties used in fluent API scenario.

    A fluent API allows setting multiple properties using a single statement by supporting so-called method chaining: Methods for setting a property value do not return void, but an object which can be called for setting another property. An example of such a fluent API could look as follows: 

     public class FooBuilder {
     public FooBuilder setFooProperty1(String value) {
        ...
        return this;
    }

     public FooBuilder setFooProperty2(int value) {
        ...
        return this;
    }
 }

    Per default, PropertyUtils does not detect methods like this because, having a non-void return type, they violate the Java Beans specification.

    This class is more tolerant with regards to the return type of a set method. It basically iterates over all methods of a class and filters them for a configurable prefix (the default prefix is set). It then generates corresponding PropertyDescriptor objects for the methods found which use these methods as write methods.

    An instance of this class is intended to collaborate with a DefaultBeanIntrospector object. So best results are achieved by adding this instance as custom BeanIntrospector after the DefaultBeanIntrospector object. Then default introspection finds read-only properties because it does not detect the write methods with a non-void return type. FluentPropertyBeanIntrospector completes the descriptors for these properties by setting the correct write method.

    Since:
    1.9

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String DEFAULT_WRITE_METHOD_PREFIX
      The default prefix for write methods.
      private org.apache.commons.logging.Log log
      The logger.
      private java.lang.String writeMethodPrefix
      The prefix of write methods to search for.

    • Constructor Summary

      Constructors 
      Constructor Description
      FluentPropertyBeanIntrospector()
      Creates a new instance of FluentPropertyBeanIntrospector and sets the default prefix for write methods.
      FluentPropertyBeanIntrospector​(java.lang.String writePrefix)
      Creates a new instance of FluentPropertyBeanIntrospector and initializes it with the prefix for write methods used by the classes to be inspected.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private java.beans.PropertyDescriptor createFluentPropertyDescritor​(java.lang.reflect.Method m, java.lang.String propertyName)
      Creates a property descriptor for a fluent API property.
      java.lang.String getWriteMethodPrefix()
      Returns the prefix for write methods this instance scans for.
      void introspect​(IntrospectionContext icontext)
      Performs introspection.
      private java.lang.String propertyName​(java.lang.reflect.Method m)
      Derives the name of a property from the given set method.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • DEFAULT_WRITE_METHOD_PREFIX

        public static final java.lang.String DEFAULT_WRITE_METHOD_PREFIX
        The default prefix for write methods.
        See Also:
        Constant Field Values

      • log

        private final org.apache.commons.logging.Log log
        The logger.

      • writeMethodPrefix

        private final java.lang.String writeMethodPrefix
        The prefix of write methods to search for.

    • Constructor Detail

      • FluentPropertyBeanIntrospector

        public FluentPropertyBeanIntrospector()
        Creates a new instance of FluentPropertyBeanIntrospector and sets the default prefix for write methods.

      • FluentPropertyBeanIntrospector

        public FluentPropertyBeanIntrospector​(java.lang.String writePrefix)
        Creates a new instance of FluentPropertyBeanIntrospector and initializes it with the prefix for write methods used by the classes to be inspected.
        Parameters:
        writePrefix - the prefix for write methods (must not be null)
        Throws:
        java.lang.IllegalArgumentException - if the prefix is null

    • Method Detail

      • createFluentPropertyDescritor

        private java.beans.PropertyDescriptor createFluentPropertyDescritor​(java.lang.reflect.Method m,
                                                                    java.lang.String propertyName)
                                                             throws java.beans.IntrospectionException
        Creates a property descriptor for a fluent API property.
        Parameters:
        m - the set method for the fluent API property
        propertyName - the name of the corresponding property
        Returns:
        the descriptor
        Throws:
        java.beans.IntrospectionException - if an error occurs

      • getWriteMethodPrefix

        public java.lang.String getWriteMethodPrefix()
        Returns the prefix for write methods this instance scans for.
        Returns:
        the prefix for write methods

      • introspect

        public void introspect​(IntrospectionContext icontext)
                throws java.beans.IntrospectionException
        Performs introspection. This method scans the current class's methods for property write methods which have not been discovered by default introspection.
        Specified by:
        introspect in interface BeanIntrospector
        Parameters:
        icontext - the introspection context
        Throws:
        java.beans.IntrospectionException - if an error occurs

      • propertyName

        private java.lang.String propertyName​(java.lang.reflect.Method m)
        Derives the name of a property from the given set method.
        Parameters:
        m - the method
        Returns:
        the corresponding property name