Package one.x1f.sip.foundation.core.util

Class ChecksumHelper

java.lang.Object

one.x1f.sip.foundation.core.util.ChecksumHelper

public class ChecksumHelper
extends Object

Utility class for building Checksums

Field Summary

Fields

Modifier and Type	Field	Description
static final LambdaHelper.ThrowingComparator<org.springframework.core.io.Resource>	DEFAULT_RESOURCE_COMPARATOR	Comparator for Resources that uses URIs for comparison.

Constructor Summary

Constructors

Constructor	Description
ChecksumHelper()

Method Summary

Modifier and Type	Method	Description
static String	calcualteReproducibleHashForResources(Collection<org.springframework.core.io.Resource> resources, String algorithm, Optional<Comparator<org.springframework.core.io.Resource>> comparator)	Builds a reproducible hash over the given resources with the selected hashing- algorithm.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT_RESOURCE_COMPARATOR

public static final LambdaHelper.ThrowingComparator<org.springframework.core.io.Resource> DEFAULT_RESOURCE_COMPARATOR

Comparator for Resources that uses URIs for comparison.

Constructor Details

ChecksumHelper

public ChecksumHelper()

Method Details

calcualteReproducibleHashForResources

public static String calcualteReproducibleHashForResources(Collection<org.springframework.core.io.Resource> resources,
 String algorithm,
 Optional<Comparator<org.springframework.core.io.Resource>> comparator)
                                                    throws IOException

Builds a reproducible hash over the given resources with the selected hashing- algorithm.

To make the hashes reproducible, the given resources are sorted first using the given comparator before being fed into the hash digest. Therefore, two hashes on the same set of resources result only in the same, reproducible hash if the same algorithm and comparator is also used.

Parameters:

resources - Resources to use for creating the hash code

algorithm - Algorith to use (see @MessageDigestAlgorithms)

comparator - (Optional) comparator to use. If non is given, DEFAULT_RESOURCE_COMPARATOR is used

Returns:

Hash code

Throws:

IOException - Exception while reading the given resources