/*
    * SPDX-FileCopyrightText: Copyright (c) 2012-2025 Yegor Bugayenko
    * SPDX-License-Identifier: MIT
    */
   package com.jcabi.manifests;
   
   import com.jcabi.log.Logger;
   import java.io.IOException;
   import java.io.InputStream;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.Collection;
  import javax.servlet.ServletContext;
  
  /**
   * Manifests in servlet context.
   *
   * Append attributes from the web application {@code MANIFEST.MF}.
   *
   * <p>You can use this class in your own
   * {@link javax.servlet.Filter} or
   * {@link javax.servlet.ServletContextListener},
   * in order to inject {@code MANIFEST.MF} attributes to the class:
   *
   * <pre> Manifests.append(new ServletMfs(context));</pre>
   *
   * <p>The class is thread-safe.
   *
   * @since 1.0
   */
  public final class ServletMfs implements Mfs {
  
      /**
       * Servlet context.
       */
      private final transient ServletContext ctx;
  
      /**
       * Ctor.
       * @param context Context
       */
      public ServletMfs(final ServletContext context) {
          this.ctx = context;
      }
  
      @Override
      public Collection<InputStream> fetch() throws IOException {
          final URL main = this.ctx.getResource("/META-INF/MANIFEST.MF");
          final Collection<InputStream> streams = new ArrayList<>(1);
          if (main == null) {
              Logger.warn(this, "MANIFEST.MF not found in WAR package");
          } else {
              streams.add(main.openStream());
          }
          return streams;
      }
  
  }