com.appslandia.plum.base.RequestAttributes Maven / Gradle / Ivy

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// The MIT License (MIT)
// Copyright © 2015 AppsLandia. All rights reserved.

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

package com.appslandia.plum.base;

import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.function.Function;

import jakarta.servlet.http.HttpServletRequest;

/**
 *
 * @author Loc Ha
 *
 */
public class RequestAttributes {

  final Map storedAttributes = new HashMap<>();

  public RequestAttributes(HttpServletRequest request) {
    this(request, (attr) -> true);
  }

  public RequestAttributes(HttpServletRequest request, Function storeSelector) {
    Enumeration attributes = request.getAttributeNames();
    while (attributes.hasMoreElements()) {
      String attribute = attributes.nextElement();

      if (storeSelector.apply(attribute)) {
        this.storedAttributes.put(attribute, request.getAttribute(attribute));
      }
    }
  }

  public void restore(HttpServletRequest request) {
    Enumeration attributes = request.getAttributeNames();
    Set needToRemove = null;

    while (attributes.hasMoreElements()) {
      String attribute = attributes.nextElement();

      if (!this.storedAttributes.containsKey(attribute)) {
        if (needToRemove == null) {
          needToRemove = new HashSet<>();
        }
        needToRemove.add(attribute);
      }
    }

    if (needToRemove != null) {
      for (String attribute : needToRemove) {
        request.removeAttribute(attribute);
      }
    }

    for (Entry attribute : this.storedAttributes.entrySet()) {
      request.setAttribute(attribute.getKey(), attribute.getValue());
    }
  }
}