How to use

ActionRequestWrapper

in

javax.portlet.filter

@Override
public String getParameter(String name) {
  String[] values = _params.get(name);
  if (_inherit && (values == null)) {
    return super.getParameter(name);
  }
  if (ArrayUtil.isNotEmpty(values)) {
    return values[0];
  }
  return null;
}

@Override
public Map<String, String[]> getParameterMap() {
  Map<String, String[]> map = new HashMap<>();
  if (_inherit) {
    map.putAll(super.getParameterMap());
  }
  map.putAll(_params);
  return map;
}

@Override
public Enumeration<String> getParameterNames() {
  Set<String> names = new LinkedHashSet<>();
  if (_inherit) {
    Enumeration<String> enu = super.getParameterNames();
    while (enu.hasMoreElements()) {
      names.add(enu.nextElement());
    }
  }
  names.addAll(_params.keySet());
  return Collections.enumeration(names);
}

@Override
public String[] getParameterValues(String name) {
  String[] values = _params.get(name);
  if (_inherit && (values == null)) {
    return super.getParameterValues(name);
  }
  return values;
}

@Override
public Principal getUserPrincipal() {
  if (_userPrincipal != null) {
    return _userPrincipal;
  }
  return super.getUserPrincipal();
}

@Override
public String getRemoteUser() {
  if (_remoteUser != null) {
    return _remoteUser;
  }
  return super.getRemoteUser();
}

@Override
public String[] getParameterValues(String name) {
  String[] values = getMultipartParameters().get(name);
  if (values != null) {
    return values;
  }
  return super.getParameterValues(name);
}

public Principal getUserPrincipal() {
  if (_userPrincipal != null) {
    return _userPrincipal;
  }
  else {
    return super.getUserPrincipal();
  }
}

public String getRemoteUser() {
  if (_remoteUser != null) {
    return _remoteUser;
  }
  else {
    return super.getRemoteUser();
  }
}

@Override
public Enumeration<String> getParameterNames() {
  Set<String> paramNames = new HashSet<String>();
  Enumeration<String> paramEnum = super.getParameterNames();
  while (paramEnum.hasMoreElements()) {
    paramNames.add(paramEnum.nextElement());
  }
  paramNames.addAll(getMultipartParameters().keySet());
  return Collections.enumeration(paramNames);
}

@Override
public String getParameter(String name) {
  String[] values = getMultipartParameters().get(name);
  if (values != null) {
    return (values.length > 0 ? values[0] : null);
  }
  return super.getParameter(name);
}

@Override
public String[] getParameterValues(String name) {
  String[] values = getMultipartParameters().get(name);
  if (values != null) {
    return values;
  }
  return super.getParameterValues(name);
}

@Override
public Map<String, String[]> getParameterMap() {
  Map<String, String[]> paramMap = new HashMap<String, String[]>();
  paramMap.putAll(super.getParameterMap());
  paramMap.putAll(getMultipartParameters());
  return paramMap;
}

@Override
public Enumeration<String> getParameterNames() {
  Set<String> paramNames = new HashSet<String>();
  Enumeration paramEnum = super.getParameterNames();
  while (paramEnum.hasMoreElements()) {
    paramNames.add((String) paramEnum.nextElement());
  }
  paramNames.addAll(getMultipartParameters().keySet());
  return Collections.enumeration(paramNames);
}

@Override
public String getParameter(String name) {
  String[] values = getMultipartParameters().get(name);
  if (values != null) {
    return (values.length > 0 ? values[0] : null);
  }
  return super.getParameter(name);
}

@Override
@SuppressWarnings("unchecked")
public Map<String, String[]> getParameterMap() {
  Map<String, String[]> paramMap = new HashMap<String, String[]>();
  paramMap.putAll(super.getParameterMap());
  paramMap.putAll(getMultipartParameters());
  return paramMap;
}