/*
 * Copyright DataStax, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.datastax.oss.driver.internal.core.util;

import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableSet;

A set of driver optional dependencies and a common mechanism to test the presence of such
dependencies on the application's classpath.
/**
 * A set of driver optional dependencies and a common mechanism to test the presence of such
 * dependencies on the application's classpath.
 */
public enum DependencyCheck {
  SNAPPY("org.xerial.snappy.Snappy"),
  LZ4("net.jpountz.lz4.LZ4Compressor"),
  ESRI("com.esri.core.geometry.ogc.OGCGeometry"),
  TINKERPOP(
      // gremlin-core
      "org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal",
      // tinkergraph-gremlin
      "org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerIoRegistryV3d0"),
  REACTIVE_STREAMS("org.reactivestreams.Publisher"),
  JACKSON(
      // jackson-core
      "com.fasterxml.jackson.core.JsonParser",
      // jackson-databind
      "com.fasterxml.jackson.databind.ObjectMapper"),
  ;

  
The fully-qualified name of classes that must exist for the dependency to work properly; we use
them to test the presence of the whole dependency on the classpath, including its transitive
dependencies if applicable. This assumes that if these classes are present, then the entire
library is present and functional, and vice versa.
Note: some of the libraries declared here may be shaded; in these cases the shade plugin will replace the package names listed above with names starting with 
com.datastax.oss.driver.shaded.*, but the presence check would still work as expected. /**
   * The fully-qualified name of classes that must exist for the dependency to work properly; we use
   * them to test the presence of the whole dependency on the classpath, including its transitive
   * dependencies if applicable. This assumes that if these classes are present, then the entire
   * library is present and functional, and vice versa.
   *
   * <p>Note: some of the libraries declared here may be shaded; in these cases the shade plugin
   * will replace the package names listed above with names starting with {@code
   * com.datastax.oss.driver.shaded.*}, but the presence check would still work as expected.
   */
  @SuppressWarnings("ImmutableEnumChecker")
  private final ImmutableSet<String> fqcns;

  DependencyCheck(String... fqcns) {
    this.fqcns = ImmutableSet.copyOf(fqcns);
  }

  
Checks if the dependency is present on the application's classpath and is loadable.
Returns:
true if the dependency is present and loadable, false otherwise./**
   * Checks if the dependency is present on the application's classpath and is loadable.
   *
   * @return true if the dependency is present and loadable, false otherwise.
   */
  public boolean isPresent() {
    for (String fqcn : fqcns) {
      // Always use the driver class loader, assuming that the driver classes and
      // the dependency classes are either being loaded by the same class loader,
      // or – as in OSGi deployments – by two distinct, but compatible class loaders.
      if (Reflection.loadClass(null, fqcn) == null) {
        return false;
      }
    }
    return true;
  }
}