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.<Person>builder()
         .setLeft(this)
         .setRight(obj)
         .setStyle(ToStringStyle.SHORT_PREFIX_STYLE))
         .build()
       .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).

See ReflectionDiffBuilder for a reflection based version of this class.

Since:
3.3
See Also:

  • Constructor Details

    • DiffBuilder

      @Deprecated public DiffBuilder(T left, T right, ToStringStyle style)
      Deprecated.
      Use DiffBuilder.Builder.
      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:
      left - this object
      right - the object to diff against
      style - the style to use when outputting the objects, null uses the default
      Throws:
      NullPointerException - if lhs or rhs is null

    • DiffBuilder

      @Deprecated public DiffBuilder(T left, T right, ToStringStyle style, boolean testObjectsEquals)
      Deprecated.
      Use DiffBuilder.Builder.
      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:
      left - this object
      right - the object to diff against
      style - the style to use when outputting the objects, null uses the default
      testObjectsEquals - 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:
      NullPointerException - if lhs or rhs is null
      Since:
      3.4

  • Method Details

    • builder

      public static <T> DiffBuilder.Builder<T> builder()
      Constructs a new DiffBuilder.Builder.
      Type Parameters:
      T - type of the left and right object.
      Returns:
      a new DiffBuilder.Builder.
      Since:
      3.15.0

    • append

      public DiffBuilder<T> append(String fieldName, boolean lhs, boolean rhs)
      Tests if two booleans are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side boolean
      rhs - the right-hand side boolean
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, boolean[] lhs, boolean[] rhs)
      Tests if two boolean[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side boolean[]
      rhs - the right-hand side boolean[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, byte lhs, byte rhs)
      Tests if two bytes are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side byte
      rhs - the right-hand side byte
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, byte[] lhs, byte[] rhs)
      Tests if two byte[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side byte[]
      rhs - the right-hand side byte[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, char lhs, char rhs)
      Tests if two chars are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side char
      rhs - the right-hand side char
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, char[] lhs, char[] rhs)
      Tests if two char[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side char[]
      rhs - the right-hand side char[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, DiffResult<?> diffResult)
      Appends diffs from another DiffResult.

      Useful this method 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 instance.
      Throws:
      NullPointerException - if field name is null or diffResult is null
      Since:
      3.5

    • append

      public DiffBuilder<T> append(String fieldName, double lhs, double rhs)
      Tests if two doubles are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side double
      rhs - the right-hand side double
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, double[] lhs, double[] rhs)
      Tests if two double[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side double[]
      rhs - the right-hand side double[]
      Returns:
      this instance.
      Throws:
      NullPointerException - 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 side float
      rhs - the right-hand side float
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, float[] lhs, float[] rhs)
      Tests if two float[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side float[]
      rhs - the right-hand side float[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, int lhs, int rhs)
      Tests if two ints are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side int
      rhs - the right-hand side int
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, int[] lhs, int[] rhs)
      Tests if two int[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side int[]
      rhs - the right-hand side int[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, long lhs, long rhs)
      Tests if two longs are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side long
      rhs - the right-hand side long
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, long[] lhs, long[] rhs)
      Tests if two long[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side long[]
      rhs - the right-hand side long[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, Object lhs, Object rhs)
      Tests if two Objectss are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side Object
      rhs - the right-hand side Object
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, Object[] lhs, Object[] rhs)
      Tests if two Object[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side Object[]
      rhs - the right-hand side Object[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, short lhs, short rhs)
      Tests if two shorts are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side short
      rhs - the right-hand side short
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • append

      public DiffBuilder<T> append(String fieldName, short[] lhs, short[] rhs)
      Tests if two short[]s are equal.
      Parameters:
      fieldName - the field name
      lhs - the left-hand side short[]
      rhs - the right-hand side short[]
      Returns:
      this instance.
      Throws:
      NullPointerException - if field name is null

    • 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.