AbstractPredicateProviderWrapper.java

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 * Licensed under the Apache License, Version 2.0 (the "License");
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package io.wcm.wcm.ui.granite.util.impl;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

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;

abstract class AbstractPredicateProviderWrapper implements PredicateProviderWrapper {

  private final ServiceReference<?> serviceReference;
  private final BundleContext bundleContext;
  private final Object service;
  private Method getPredicateMethod;

  protected final Logger log = LoggerFactory.getLogger(getClass());

  AbstractPredicateProviderWrapper(ServiceReference<?> serviceReference, BundleContext bundleContext) {
    this.serviceReference = serviceReference;
    this.bundleContext = bundleContext;
    service = bundleContext.getService(serviceReference);
    if (service != null) {
      try {
        getPredicateMethod = service.getClass().getMethod("getPredicate", String.class);
      }
      catch (NoSuchMethodException | SecurityException ex) {
        log.warn("Legacy PredicateProvider service does not implement expected method 'getPredicate(String)'.", ex);
      }
    }
  }

  protected @Nullable Object getPredicateInternal(@NotNull String name) {
    if (getPredicateMethod != null) {
      try {
        return getPredicateMethod.invoke(service, name);
      }
      catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
        log.warn("Error calling 'getPredicate(String)' method.", ex);
      }
    }
    return null;
  }

  @Override
  public void close() {
    bundleContext.ungetService(serviceReference);
  }

}