Package org.apache.commons.lang3.builder

Class DiffBuilder<T>

java.lang.Object
org.apache.commons.lang3.builder.DiffBuilder<T>
Type Parameters:
T - type of the left and right object.
All Implemented Interfaces:
Builder<DiffResult<T>>
public class DiffBuilder<T> extends Object implements Builder<DiffResult<T>>

Assists in implementing Diffable.diff(Object) methods.

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 DiffBuilder(this, obj, ToStringStyle.SHORT_PREFIX_STYLE)
       .append("name", this.name, obj.name)
       .append("age", this.age, obj.age)
       .append("smoker", this.smoker, obj.smoker)
       .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:
3.3
See Also:

  • Field Details

    • diffs

      private final List<Diff<?>> diffs

    • objectsTriviallyEqual

      private final boolean objectsTriviallyEqual

    • left

      private final T left

    • style

      private final ToStringStyle style

  • Constructor Details

    • DiffBuilder

      public DiffBuilder(T lhs, T rhs, ToStringStyle style, boolean testTriviallyEqual)

      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
      testTriviallyEqual - If true, this will test if lhs and rhs are the same or equal. All of the append(fieldName, lhs, rhs) methods will abort without creating a field Diff if the trivially equal test is enabled and returns true. The result of this test is never changed throughout the life of this DiffBuilder.
      Throws:
      IllegalArgumentException - if lhs or rhs is null
      Since:
      3.4

    • DiffBuilder

      public DiffBuilder(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.

      This delegates to DiffBuilder(Object, Object, ToStringStyle, boolean) with the testTriviallyEqual flag enabled.

      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

    • append

      public DiffBuilder<T> append(String fieldName, boolean lhs, boolean rhs)

      Test if two booleans are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand boolean
      rhs - the right hand boolean
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, boolean[] lhs, boolean[] rhs)

      Test if two boolean[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand boolean[]
      rhs - the right hand boolean[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, byte lhs, byte rhs)

      Test if two bytes are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand byte
      rhs - the right hand byte
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, byte[] lhs, byte[] rhs)

      Test if two byte[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand byte[]
      rhs - the right hand byte[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, char lhs, char rhs)

      Test if two chars are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand char
      rhs - the right hand char
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, char[] lhs, char[] rhs)

      Test if two char[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand char[]
      rhs - the right hand char[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, double lhs, double rhs)

      Test if two doubles are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand double
      rhs - the right hand double
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, double[] lhs, double[] rhs)

      Test if two double[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand double[]
      rhs - the right hand double[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, float lhs, float rhs)

      Test if two floats are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand float
      rhs - the right hand float
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, float[] lhs, float[] rhs)

      Test if two float[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand float[]
      rhs - the right hand float[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, int lhs, int rhs)

      Test if two ints are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand int
      rhs - the right hand int
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, int[] lhs, int[] rhs)

      Test if two int[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand int[]
      rhs - the right hand int[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, long lhs, long rhs)

      Test if two longs are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand long
      rhs - the right hand long
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, long[] lhs, long[] rhs)

      Test if two long[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand long[]
      rhs - the right hand long[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, short lhs, short rhs)

      Test if two shorts are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand short
      rhs - the right hand short
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, short[] lhs, short[] rhs)

      Test if two short[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand short[]
      rhs - the right hand short[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, Object lhs, Object rhs)

      Test if two Objectss are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand Object
      rhs - the right hand Object
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, Object[] lhs, Object[] rhs)

      Test if two Object[]s are equal.

      Parameters:
      fieldName - the field name
      lhs - the left hand Object[]
      rhs - the right hand Object[]
      Returns:
      this
      Throws:
      IllegalArgumentException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, DiffResult<T> diffResult)

      Append diffs from another DiffResult.

      This method is useful if you want to compare properties which are themselves Diffable and would like to know which specific part of it is different. 

       public class Person implements Diffable<Person> {
   String name;
   Address address; // implements Diffable<Address>

   ...

   public DiffResult diff(Person obj) {
     return new DiffBuilder(this, obj, ToStringStyle.SHORT_PREFIX_STYLE)
       .append("name", this.name, obj.name)
       .append("address", this.address.diff(obj.address))
       .build();
   }
 }
      Parameters:
      fieldName - the field name
      diffResult - the DiffResult to append
      Returns:
      this
      Throws:
      NullPointerException - if field name is null
      Since:
      3.5

    • build

      public DiffResult<T> build()

      Builds a DiffResult based on the differences appended to this builder.

      Specified by:
      build in interface Builder<T>
      Returns:
      a DiffResult containing the differences between the two objects.

    • validateFieldNameNotNull

      private void validateFieldNameNotNull(String fieldName)