Key

```
public interface Key

                    
```
An interface that uniquely identifies some put of data. Implementations must implement and hashCode. Implementations are generally expected to add all uniquely identifying information used in in equals} and hashCode} to the given MessageDigest in }, although this requirement is not as strict for partial cache key signatures.

Method Summary

Modifier and Type	Method	Description
`abstract void`	`updateDiskCacheKey(@NonNull() MessageDigest messageDigest)`	Adds all uniquely identifying information to the given digest.
`abstract boolean`	`equals(Object o)`	For caching to work correctly, implementations must implement this method and .
`abstract int`	`hashCode()`	For caching to work correctly, implementations must implement this method and .

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - updateDiskCacheKey
```
 abstract void updateDiskCacheKey(@NonNull() MessageDigest messageDigest)
```
    Adds all uniquely identifying information to the given digest.
    Note - Using reset inside of this method will resultin undefined behavior.
  - equals
```
 abstract boolean equals(Object o)
```
    For caching to work correctly, implementations must implement this method and .
  - hashCode
```
 abstract int hashCode()
```
    For caching to work correctly, implementations must implement this method and .