wro4j-core/src/main/java/ro/isdc/wro/model/resource/support/change/ResourceChangeDetector.java
public boolean checkChangeForGroup(final String uri, final String groupName) throws IOException {
    notNull(uri);
    notNull(groupName);
    LOG.debug("group={}, uri={}", groupName, uri);
    final ResourceChangeInfo resourceInfo = changeInfoMap.get(uri);
    if (resourceInfo.isCheckRequiredForGroup(groupName)) {
      final InputStream inputStream = locatorFactory.locate(uri);
      try{
        final String currentHash = hashStrategy.getHash(inputStream);
        resourceInfo.updateHashForGroup(currentHash, groupName);
      }finally{
        IOUtils.closeQuietly(inputStream);
      }
    }
    return resourceInfo.isChanged(groupName);
  }
public boolean checkChangeForGroup(final String uri, final String groupName) throws IOException {
    notNull(uri);
    notNull(groupName);
    LOG.debug("group={}, uri={}", groupName, uri);
    final ResourceChangeInfo resourceInfo = changeInfoMap.get(uri);
    if (resourceInfo.isCheckRequiredForGroup(groupName)) {
      final InputStream inputStream = locatorFactory.locate(uri);
      try{
        final String currentHash = hashStrategy.getHash(inputStream);
        resourceInfo.updateHashForGroup(currentHash, groupName);
      }finally{
        IOUtils.closeQuietly(inputStream);
      }
    }
    return resourceInfo.isChanged(groupName);
  }
Check if an uri from a particular group has changed.

@param uri
the uri to check for change.
@param groupName
the name of the group where the uri belongs to.
@return true if the change is detected for the provided uri.