ERSCachingData (Bouncy Castle Library 1.86 API Specification)

java.lang.Object
- org.bouncycastle.tsp.ers.ERSCachingData

All Implemented Interfaces:

ERSData

Direct Known Subclasses:

ERSByteData, ERSDataGroup, ERSFileData, ERSInputStreamData
```
public abstract class ERSCachingData
extends java.lang.Object
implements ERSData
```
Base ERSData implementation that caches calculated hashes, keyed by digest algorithm and previous-chain hash, so the (potentially expensive) hash of a data object is computed only once per combination. Subclasses supply the actual hash in calculateHash(DigestCalculator, byte[]).

Constructor Summary

Constructors
Constructor Description

ERSCachingData()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected abstract byte[]`	`calculateHash(DigestCalculator digestCalculator, byte[] previousChainHash)`	Compute the hash for this data object.
`byte[]`	`getHash(DigestCalculator digestCalculator, byte[] previousChainHash)`	Return the hash for this data object, computing it (via the subclass) on first request and returning the cached value thereafter.

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

- Constructor Detail
  - ERSCachingData
```
public ERSCachingData()
```
- Method Detail
  - getHash
```
public byte[] getHash(DigestCalculator digestCalculator,
                      byte[] previousChainHash)
```
    Return the hash for this data object, computing it (via the subclass) on first request and returning the cached value thereafter.
    
    Specified by:
    
    getHash in interface ERSData
    
    Parameters:
    
    digestCalculator - the DigestCalculator to use for computing the hash.
    
    previousChainHash - hash from an earlier chain to fold in, or null.
    
    Returns:
    
    the calculated hash for this data object.
  - calculateHash
```
protected abstract byte[] calculateHash(DigestCalculator digestCalculator,
                                        byte[] previousChainHash)
```
    Compute the hash for this data object. Implemented by subclasses; the result is cached by getHash(DigestCalculator, byte[]).
    
    Parameters:
    
    digestCalculator - the digest calculator to use.
    
    previousChainHash - hash from an earlier chain to fold in, or null.
    
    Returns:
    
    the calculated hash.