[jira] [Updated] (LANG-1493) Performance of Reflection for equals and hash code can be improved over EqualsBuilder

["Miguel Munoz (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/LANG-1493?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Miguel Munoz updated LANG-1493:
-------------------------------
    Description: 
The EqualsBuilder.reflectionEquals() method is very inefficient. It reflects through all the fields of a class every time it needs to do a comparison. A faster approach would be to do the reflection once when the class loads, and re-use it for each instance. This change, however, needs a different API and couldn't be a drop-in replacement for EqualsBuilder. Instead it would need to be a new class.
 I have written a class that can do this. Performance tests show that it runs up to 20 times faster, depending on how many fields it needs to compare before finding a difference.

You can try the class out by going to [https://github.com/SwingGuy1024/DogTags].

The API currently works like this:
 
{code:java}
public class MyClass {
  // fields and methods
  
  private static final DogTag<MyClass> dogTag = DogTag.from(MyClass.class);
  
  @Override
  public boolean equals(Object that) {
    return dogTag.doEqualsTest(this, that);
  }
  
  @Override
  public int hashCode() {
    return dogTag.doHashCode(this);
  }
}{code}

I'm looking into changing the API, so it would work like this:


{code:java}
public class MyClass {
  // fields and methods here ...
  
  private final DogTag<MyClass> dogTag = DogTag.from(MyClass.class, this);
  
  @Override
  public boolean equals(Object other) {
    return dogTag.doEqualsTest(other);
  }
  
  @Override
  public int hashCode() {
    return dogTag.doHashCode();
  }
}
{code}

(I'm a new contributor, so I'm not sure if this is the best way to suggest a whole new class. But I'd like to contribute to give people a faster way of doing Reflection Equals.)

  was:
The EqualsBuilder class is very inefficient. It reflects through all the fields of a class every time it needs to do a comparison. A faster approach would be to do the reflection once when the class loads, and re-use it for each instance. This change, however, needs a different API and couldn't be a drop-in replacement for EqualsBuilder. Instead it would need to be a new class.
 I have written a class that can do this. Performance tests show that it runs up to 20 times faster, depending on how many fields it needs to compare before finding a difference.

You can try the class out by going to [https://github.com/SwingGuy1024/DogTags].

The API currently works like this:
 
{code:java}
public class MyClass {
  // fields and methods
  
  private static final DogTag<MyClass> dogTag = DogTag.from(MyClass.class);
  
  @Override
  public boolean equals(Object that) {
    return dogTag.doEqualsTest(this, that);
  }
  
  @Override
  public int hashCode() {
    return dogTag.doHashCode(this);
  }
}{code}

I'm looking into changing the API, so it would work like this:


{code:java}
public class MyClass {
  // fields and methods here ...
  
  private final DogTag<MyClass> dogTag = DogTag.from(MyClass.class, this);
  
  @Override
  public boolean equals(Object other) {
    return dogTag.doEqualsTest(other);
  }
  
  @Override
  public int hashCode() {
    return dogTag.doHashCode();
  }
}
{code}

(I'm a new contributor, so I'm not sure if this is the best way to suggest a whole new class. But I'd like to contribute to give people a faster way of doing Reflection Equals.)


> Performance of Reflection for equals and hash code can be improved over EqualsBuilder
> -------------------------------------------------------------------------------------
>
>                 Key: LANG-1493
>                 URL: https://issues.apache.org/jira/browse/LANG-1493
>             Project: Commons Lang
>          Issue Type: New Feature
>          Components: lang.*
>            Reporter: Miguel Munoz
>            Priority: Major
>   Original Estimate: 672h
>  Remaining Estimate: 672h
>
> The EqualsBuilder.reflectionEquals() method is very inefficient. It reflects through all the fields of a class every time it needs to do a comparison. A faster approach would be to do the reflection once when the class loads, and re-use it for each instance. This change, however, needs a different API and couldn't be a drop-in replacement for EqualsBuilder. Instead it would need to be a new class.
>  I have written a class that can do this. Performance tests show that it runs up to 20 times faster, depending on how many fields it needs to compare before finding a difference.
> You can try the class out by going to [https://github.com/SwingGuy1024/DogTags].
> The API currently works like this:
>  
> {code:java}
> public class MyClass {
>   // fields and methods
>   
>   private static final DogTag<MyClass> dogTag = DogTag.from(MyClass.class);
>   
>   @Override
>   public boolean equals(Object that) {
>     return dogTag.doEqualsTest(this, that);
>   }
>   
>   @Override
>   public int hashCode() {
>     return dogTag.doHashCode(this);
>   }
> }{code}
> I'm looking into changing the API, so it would work like this:
> {code:java}
> public class MyClass {
>   // fields and methods here ...
>   
>   private final DogTag<MyClass> dogTag = DogTag.from(MyClass.class, this);
>   
>   @Override
>   public boolean equals(Object other) {
>     return dogTag.doEqualsTest(other);
>   }
>   
>   @Override
>   public int hashCode() {
>     return dogTag.doHashCode();
>   }
> }
> {code}
> (I'm a new contributor, so I'm not sure if this is the best way to suggest a whole new class. But I'd like to contribute to give people a faster way of doing Reflection Equals.)



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