code: public synchronized void set( Artifact artifact, InputStream content )
          throws IOException
      {
          Map<String, Map<String, Map<Artifact, Content>>> artifactMap = contents.get( artifact.getGroupId() );
          if ( artifactMap == null )
          {
              artifactMap = new HashMap<String, Map<String, Map<Artifact, Content>>>();
              contents.put( artifact.getGroupId(), artifactMap );
          }
          Map<String, Map<Artifact, Content>> versionMap = artifactMap.get( artifact.getArtifactId() );
          if ( versionMap == null )
          {
              versionMap = new HashMap<String, Map<Artifact, Content>>();
              artifactMap.put( artifact.getArtifactId(), versionMap );
          }
          Map<Artifact, Content> filesMap = versionMap.get( artifact.getVersion() );
          if ( filesMap == null )
          {
              filesMap = new HashMap<Artifact, Content>();
              versionMap.put( artifact.getVersion(), filesMap );
          }
          try
          {
              filesMap.put( artifact, new Content( IOUtils.toByteArray( content ) ) );
          }
          finally
          {
              IOUtils.closeQuietly( content );
          }
      }
docs: {@inheritDoc}