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Correct javadoc of the hash function signature.

This commit is contained in:
aherbert 2020-03-12 15:17:39 +00:00
parent 9f2271334d
commit 33d6ddc7f9
2 changed files with 31 additions and 13 deletions
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16
src/main/java/org/apache/commons/collections4/bloomfilter/hasher/HashFunction.java
View File

@ -30,4 +30,20 @@ public interface HashFunction extends HashFunctionIdentity {
* @return the long value of the hash.
*/
long apply(byte[] buffer, int seed);
/**
* Gets the signature of this function.
*
* <p>The signature of this function is calculated as:
* <pre><code>
* int seed = 0;
* apply(String.format("%s-%s-%s",
* getName().toUpperCase(Locale.ROOT), getSignedness(), getProcess())
* .getBytes("UTF-8"), seed);
* </code></pre>
*
* @see HashFunctionIdentity#prepareSignatureBuffer(HashFunctionIdentity)
*/
@Override
long getSignature();
}

28
src/main/java/org/apache/commons/collections4/bloomfilter/hasher/HashFunctionIdentity.java
View File

@ -98,16 +98,18 @@ public interface HashFunctionIdentity {
}
/**
* Gets the signature buffer for a HashFunctionIdentity.
* <p>
* The signature of this function is calculated as:
* {@code
* apply( String.format( "%s-%s-%s", getName().toUpperCase( Locale.ROOT ), getSignedness(), getProcess() )
* .getBytes( "UTF-8" ), 0 );
* }
* </p>
* Gets a {@code byte[]} buffer for a HashFunctionIdentity to create a signature. The
* {@code byte[]} is composed using properties of the hash function as:
*
* <pre><code>
* String.format("%s-%s-%s",
* getName().toUpperCase(Locale.ROOT), getSignedness(), getProcess())
* .getBytes("UTF-8");
* </code></pre>
*
* @param identity The HashFunctionIdentity to create the buffer for.
* @return the signature buffer for the identity
* @see #getSignature()
*/
static byte[] prepareSignatureBuffer(final HashFunctionIdentity identity) {
return String.format("%s-%s-%s",
@ -144,13 +146,13 @@ public interface HashFunctionIdentity {
String getProvider();
/**
* Gets the signature of this function. <p> The signature of this function is
* calculated as: {@code
* apply( String.format( "%s-%s-%s", getName(), getSignedness(), getProcess() )
* .getBytes( "UTF-8" ), 0 );
* } </p>
* Gets the signature of this function. The signature is the output of the hash function
* when applied to a set of bytes composed using properties of the hash function.
*
* <p>Implementations should define the method used to generate the signature.
*
* @return the signature of this function.
* @see #prepareSignatureBuffer(HashFunctionIdentity)
*/
long getSignature();