package com.atlassian.plugin.factories;
   
   import com.atlassian.plugin.Application;
   import com.atlassian.plugin.PluginArtifact;
   import com.atlassian.plugin.PluginParseException;
   import com.atlassian.plugin.parsers.DescriptorParser;
   import com.atlassian.plugin.parsers.DescriptorParserFactory;
   
   import java.io.InputStream;
  import java.util.Set;
  import java.util.function.Predicate;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  import static org.apache.commons.io.IOUtils.closeQuietly;
  
  /**
   * @since 3.0
   */
  public abstract class AbstractPluginFactory implements PluginFactory {
  
      protected final DescriptorParserFactory descriptorParserFactory;
      protected final Set<Application> applications;
  
      protected AbstractPluginFactory(DescriptorParserFactory descriptorParserFactory, Set<Application> applications) {
          this.descriptorParserFactory = checkNotNull(descriptorParserFactory);
          this.applications = checkNotNull(applications);
      }
  
      /**
       * Determines if this deployer can handle this artifact by looking for the plugin descriptor
       *
       * @param pluginArtifact The artifact to test
       * @return The plugin key, null if it cannot load the plugin
       * @throws com.atlassian.plugin.PluginParseException If there are exceptions parsing the plugin configuration
       */
      public String canCreate(PluginArtifact pluginArtifact) throws PluginParseException {
          return getPluginKeyFromDescriptor(pluginArtifact);
      }
  
      protected final boolean hasDescriptor(PluginArtifact pluginArtifact) {
          InputStream descriptorStream = null;
          try {
              descriptorStream = getDescriptorInputStream(pluginArtifact);
              return descriptorStream != null;
          } finally {
              closeQuietly(descriptorStream);
          }
      }
  
      protected final String getPluginKeyFromDescriptor(PluginArtifact pluginArtifact) {
          String pluginKey = null;
          InputStream descriptorStream = null;
          try {
              descriptorStream = getDescriptorInputStream(pluginArtifact);
              if (descriptorStream != null) {
                  final DescriptorParser descriptorParser = descriptorParserFactory.getInstance(descriptorStream, applications);
                  if (isValidPluginsVersion().test(descriptorParser.getPluginsVersion())) {
                      pluginKey = descriptorParser.getKey();
                  }
              }
          } finally {
              closeQuietly(descriptorStream);
          }
          return pluginKey;
      }
  
      protected abstract InputStream getDescriptorInputStream(PluginArtifact pluginArtifact);
  
      protected abstract Predicate<Integer> isValidPluginsVersion();
  }