@Override
    public Map<String, Object> getParameters() {
        return unmodifiableMap(this.parameters);
    }
Creates a new SimpleHashRequest instance.

@param algorithmName the name of the hash algorithm to use.  This is often null as the
                     {@link HashService} implementation is usually configured with an
                     appropriate algorithm name, but this can be non-null
                     if the hash service's algorithm should be overridden with a
                     specific one for the duration of the request.
@param source        the source to be hashed
@param salt          any public salt which should be used when computing the hash
@param parameters    e.g. the number of hash iterations to execute or other parameters.
@throws NullPointerException if {@code source} is null or empty or {@code parameters} is {@code null}.
crypto/hash/src/main/java/org/apache/shiro/crypto/hash/SimpleHashRequest.java