Package org.apache.commons.lang3.builder

Class ReflectionDiffBuilder<T>

java.lang.Object

org.apache.commons.lang3.builder.ReflectionDiffBuilder<T>

Type Parameters:

T - type of the left and right object to diff.

All Implemented Interfaces:

Builder<DiffResult<T>>

public class ReflectionDiffBuilder<T>
extends Object
implements Builder<DiffResult<T>>

Assists in implementing Diffable.diff(Object) methods.

All non-static, non-transient fields (including inherited fields) of the objects to diff are discovered using reflection and compared for differences.

To use this class, write code as follows:

 public class Person implements Diffable<Person> {
   String name;
   int age;
   boolean smoker;
   ...

   public DiffResult diff(Person obj) {
     // No need for null check, as NullPointerException correct if obj is null
     return new ReflectionDiffBuilder(this, obj, ToStringStyle.SHORT_PREFIX_STYLE)
       .build();
   }
 }
 

The ToStringStyle passed to the constructor is embedded in the returned DiffResult and influences the style of the DiffResult.toString() method. This style choice can be overridden by calling DiffResult.toString(ToStringStyle).

Since:

3.6

See Also:

• Diffable
• Diff
• DiffResult
• ToStringStyle

Field Summary

Fields

Modifier and Type	Field	Description
private final DiffBuilder<T>	diffBuilder
private final Object	left
private final Object	right

Constructor Summary

Constructors

Constructor	Description
ReflectionDiffBuilder(T lhs, T rhs, ToStringStyle style)	Constructs a builder for the specified objects with the specified style.

Method Summary

Modifier and Type	Method	Description
private boolean	accept(Field field)
private void	appendFields(Class<?> clazz)
DiffResult<T>	build()	Returns a reference to the object being constructed or result being calculated by the builder.

Methods inherited from class java.lang.Object

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

Field Details

left

private final Object left

right

private final Object right

diffBuilder

private final DiffBuilder<T> diffBuilder

Constructor Details

ReflectionDiffBuilder

public ReflectionDiffBuilder(T lhs,
 T rhs,
 ToStringStyle style)

Constructs a builder for the specified objects with the specified style.

If lhs == rhs or lhs.equals(rhs) then the builder will not evaluate any calls to append(...) and will return an empty DiffResult when build() is executed.

Parameters:

lhs - this object

rhs - the object to diff against

style - the style will use when outputting the objects, null uses the default

Throws:

IllegalArgumentException - if lhs or rhs is null

Method Details

build

public DiffResult<T> build()

Description copied from interface: Builder

Returns a reference to the object being constructed or result being calculated by the builder.

Specified by:

build in interface Builder<T>

Returns:

the object constructed or result calculated by the builder.

appendFields

private void appendFields(Class<?> clazz)

accept

private boolean accept(Field field)