code: public DependencyCustomizer ifAllResourcesPresent(String... paths) {
  		return new DependencyCustomizer(this) {
  			@Override
  			protected boolean canAdd() {
  				for (String path : paths) {
  					try {
  						if (DependencyCustomizer.this.loader.getResource(path) == null) {
  							return false;
  						}
  						return true;
  					}
  					catch (Exception ex) {
  						// swallow exception and continue
  					}
  				}
  				return DependencyCustomizer.this.canAdd();
  			}
  		};
  	}
docs: Create a nested {@link DependencyCustomizer} that only applies if the specified
  paths are on the class path.
  @param paths the paths to test
  @return a nested {@link DependencyCustomizer}