public void setFormatClassNames(Map<String, String> formatClassNames) {
        this.formatClassNames = formatClassNames;
    }
Sets the {@code hash-format-alias}-to-{@code fullyQualifiedHashFormatClassNameImplementation} map to be used in
the {@link #getInstance(String)} implementation.  See the {@link #getFormatClassNames()} JavaDoc for more
information.
<h3>Efficiency</h3>
Populating this map will be more efficient than configuring {@link #getSearchPackages() searchPackages},
but search packages may be more convenient depending on the number of {@code HashFormat} implementations that
need to be supported by this factory.

@param formatClassNames the {@code hash-format-alias}-to-{@code fullyQualifiedHashFormatClassNameImplementation}
                        map to be used in the {@link #getInstance(String)} implementation.
crypto/hash/src/main/java/org/apache/shiro/crypto/hash/format/DefaultHashFormatFactory.java