001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.http.classic.header;
018
019import static org.apache.juneau.commons.utils.Shorts.*;
020
021import java.util.*;
022
023import org.apache.http.*;
024import org.apache.juneau.commons.utils.*;
025
026/**
027 * Basic implementation of a {@link HeaderIterator}.
028 *
029 * <h5 class='section'>Notes:</h5><ul>
030 *    <li class='warn'>This class is not thread safe.
031 * </ul>
032 *
033 * <h5 class='section'>See Also:</h5><ul>
034 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauRestCommon">juneau-rest-common</a>
035 *    <li class='extlink'><a class="doclink" href="https://www.w3.org/Protocols/rfc2616/rfc2616.html">Hypertext Transfer Protocol -- HTTP/1.1</a>
036 * </ul>
037 */
038@SuppressWarnings({
039   "java:S1192" // Duplicated literals (argument/property names) read more clearly inline than as constants
040})
041public class BasicHeaderIterator implements HeaderIterator {
042
043   private final Header[] entries;
044   private final String name;
045   private final boolean caseSensitive;
046
047   private int currentIndex;
048
049   /**
050    * Creates a new header iterator.
051    *
052    * @param headers An array of headers over which to iterate.  Must not be <jk>null</jk>.
053    * @param name The name of the headers over which to iterate, or <jk>null</jk> for all.
054    * @param caseSensitive Use case-sensitive matching for part name.
055    */
056   public BasicHeaderIterator(Header[] headers, String name, boolean caseSensitive) {
057      this.entries = reqnn("headers", headers);
058      this.name = name;
059      this.caseSensitive = caseSensitive;
060      this.currentIndex = findNext(-1);
061   }
062
063   @Override /* Overridden from HeaderIterator */
064   public boolean hasNext() {
065      return (currentIndex >= 0);
066   }
067
068   @Override /* Overridden from HeaderIterator */
069   public final Object next() throws NoSuchElementException {
070      return nextHeader();
071   }
072
073   @Override /* Overridden from HeaderIterator */
074   public Header nextHeader() throws NoSuchElementException {
075
076      int current = currentIndex;
077
078      if (current < 0)
079         throw new NoSuchElementException("Iteration already finished.");
080
081      currentIndex = findNext(current);
082
083      return entries[current];
084   }
085
086   /**
087    * Not supported.
088    */
089   @Override /* Overridden from HeaderIterator */
090   public void remove() {
091      throw uoex();
092   }
093
094   private boolean eq(String s1, String s2) {
095      return Shorts.eq(! caseSensitive, s1, s2);  // NOAI
096   }
097
098   private boolean filter(int index) {
099      return (name == null) || eq(name, entries[index].getName());
100   }
101
102   private int findNext(int pos) {
103
104      int from = pos;
105
106      int to = entries.length - 1;
107      boolean found = false;
108      while (! found && (from < to)) {
109         from++;
110         found = filter(from);
111      }
112
113      return found ? from : -1;
114   }
115}