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  package io.wcm.wcm.ui.granite.util.impl;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Objects;
  import java.util.stream.Collectors;
  
  import org.apache.commons.collections4.Predicate;
  import org.apache.sling.api.resource.Resource;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.ServiceReference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Gets predicate instances from AEM PredicateProvider.
   *
   * <p>
   * Tries to get them from latest implementation from <code>com.day.cq.commons.predicates.PredicateProvider</code>
   * first (introduced in AEMaaCS API in 2024), and if that's not available, falls back to
   * <code>com.day.cq.commons.predicate.PredicateProvider</code> (also available in AEM 6.x).
   * </p>
   */
  public final class PredicateProviderUtils {
  
    private static final String PREDICATE_PROVIDER_CLASS_NAME_LATEST = "com.day.cq.commons.predicates.PredicateProvider";
    private static final String PREDICATE_PROVIDER_CLASS_NAME_LEGACY = "com.day.cq.commons.predicate.PredicateProvider";
  
    private static final Logger log = LoggerFactory.getLogger(PredicateProviderUtils.class);
  
    private PredicateProviderUtils() {
      // static methods only
    }
  
    /**
     * Get list of predicates for given filter names.
     * @param filter Array of filter names
     * @param bundleContext OSGi bundle context
     * @return List of predicates
     */
    @SuppressWarnings({
        "java:S2583", "null", // filter may be null
        "PMD.AvoidCatchingGenericException"
    })
    public static @NotNull List<Predicate<Resource>> toPredicates(@NotNull String @Nullable [] filter, @NotNull BundleContext bundleContext) {
      if (filter == null || filter.length == 0) {
        return Collections.emptyList();
      }
      try (PredicateProviderWrapper predicateProvider = getPredicateProvider(bundleContext)) {
        return Arrays.asList(filter).stream()
          .filter(Objects::nonNull)
          .map(item -> {
            Predicate<Resource> predicate = predicateProvider.getPredicate(item);
            if (predicate != null) {
              return predicate;
            }
            else {
              log.warn("Unable to find predicate implementation for filter: {}", item);
              return null;
            }
          })
          .filter(Objects::nonNull)
          .collect(Collectors.toList());
      }
      catch (Exception ex) {
        log.warn("Unable to close predicate provider.", ex);
        return Collections.emptyList();
      }
    }
  
    private static @NotNull PredicateProviderWrapper getPredicateProvider(@NotNull BundleContext bundleContext) {
      ServiceReference<?> serviceReference = bundleContext.getServiceReference(PREDICATE_PROVIDER_CLASS_NAME_LATEST);
      if (serviceReference != null) {
        log.debug("Using latest PredicateProvider implementation: {}", PREDICATE_PROVIDER_CLASS_NAME_LATEST);
        return new LatestPredicateProviderWrapper(serviceReference, bundleContext);
      }
      serviceReference = bundleContext.getServiceReference(PREDICATE_PROVIDER_CLASS_NAME_LEGACY);
     if (serviceReference != null) {
       log.debug("Using legacy PredicateProvider implementation: {}", PREDICATE_PROVIDER_CLASS_NAME_LEGACY);
       return new LegacyPredicateProviderWrapper(serviceReference, bundleContext);
     }
     log.warn("No PredicateProvider implementation found.");
     return new FallbackPredicateProviderWrapper();
   }
 
 }