com.phloc.web.fileupload.util.FileItemHeadersImpl Maven / Gradle / Ivy

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/**
 * Copyright (C) 2006-2015 phloc systems
 * http://www.phloc.com
 * office[at]phloc[dot]com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.phloc.web.fileupload.util;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import com.phloc.commons.collections.ContainerHelper;
import com.phloc.web.fileupload.IFileItemHeaders;

/**
 * Default implementation of the {@link IFileItemHeaders} interface.
 * 
 * @author Michael C. Macaluso
 * @since 1.3
 */
public class FileItemHeadersImpl implements IFileItemHeaders, Serializable
{
  private final ReadWriteLock m_aRWLock = new ReentrantReadWriteLock ();
  /**
   * Map of String keys to a List of
   * String instances.
   */
  private final Map > m_aHeaderNameToValueListMap = new HashMap > ();

  /**
   * List to preserve order of headers as added. This would not be needed if a
   * LinkedHashMap could be used, but don't want to depend on 1.4.
   */
  private final List  m_aHeaderNameList = new ArrayList  ();

  @Nullable
  public String getHeader (@Nonnull final String sName)
  {
    m_aRWLock.readLock ().lock ();
    try
    {
      final String sNameLower = sName.toLowerCase (Locale.US);
      final List  aHeaderValueList = m_aHeaderNameToValueListMap.get (sNameLower);
      return ContainerHelper.getFirstElement (aHeaderValueList);
    }
    finally
    {
      m_aRWLock.readLock ().unlock ();
    }
  }

  @Nonnull
  public Iterator  getHeaderNames ()
  {
    m_aRWLock.readLock ().lock ();
    try
    {
      return m_aHeaderNameList.iterator ();
    }
    finally
    {
      m_aRWLock.readLock ().unlock ();
    }
  }

  @Nonnull
  public Iterator  getHeaders (@Nonnull final String name)
  {
    m_aRWLock.readLock ().lock ();
    try
    {
      final String sNameLower = name.toLowerCase (Locale.US);
      final List  aHeaderValueList = m_aHeaderNameToValueListMap.get (sNameLower);
      return ContainerHelper.getIterator (aHeaderValueList);
    }
    finally
    {
      m_aRWLock.readLock ().unlock ();
    }
  }

  /**
   * Method to add header values to this instance.
   * 
   * @param name
   *        name of this header
   * @param value
   *        value of this header
   */
  public void addHeader (@Nonnull final String name, @Nullable final String value)
  {
    m_aRWLock.writeLock ().lock ();
    try
    {
      final String sNameLower = name.toLowerCase (Locale.US);
      List  aHeaderValueList = m_aHeaderNameToValueListMap.get (sNameLower);
      if (aHeaderValueList == null)
      {
        aHeaderValueList = new ArrayList  ();
        m_aHeaderNameToValueListMap.put (sNameLower, aHeaderValueList);
        m_aHeaderNameList.add (sNameLower);
      }
      aHeaderValueList.add (value);
    }
    finally
    {
      m_aRWLock.writeLock ().unlock ();
    }
  }
}