| /* |
| * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/message/BasicListHeaderIterator.java $ |
| * $Revision: 584542 $ |
| * $Date: 2007-10-14 06:29:34 -0700 (Sun, 14 Oct 2007) $ |
| * |
| * ==================================================================== |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| */ |
| |
| package org.apache.http.message; |
| |
| |
| import java.util.List; |
| import java.util.NoSuchElementException; |
| |
| import org.apache.http.Header; |
| import org.apache.http.HeaderIterator; |
| |
| |
| /** |
| * Implementation of a {@link HeaderIterator} based on a {@link List}. |
| * For use by {@link HeaderGroup}. |
| * |
| * @version $Revision: 584542 $ |
| */ |
| public class BasicListHeaderIterator implements HeaderIterator { |
| |
| /** |
| * A list of headers to iterate over. |
| * Not all elements of this array are necessarily part of the iteration. |
| */ |
| protected final List allHeaders; |
| |
| |
| /** |
| * The position of the next header in {@link #allHeaders allHeaders}. |
| * Negative if the iteration is over. |
| */ |
| protected int currentIndex; |
| |
| |
| /** |
| * The position of the last returned header. |
| * Negative if none has been returned so far. |
| */ |
| protected int lastIndex; |
| |
| |
| /** |
| * The header name to filter by. |
| * <code>null</code> to iterate over all headers in the array. |
| */ |
| protected String headerName; |
| |
| |
| |
| /** |
| * Creates a new header iterator. |
| * |
| * @param headers a list of headers over which to iterate |
| * @param name the name of the headers over which to iterate, or |
| * <code>null</code> for any |
| */ |
| public BasicListHeaderIterator(List headers, String name) { |
| if (headers == null) { |
| throw new IllegalArgumentException |
| ("Header list must not be null."); |
| } |
| |
| this.allHeaders = headers; |
| this.headerName = name; |
| this.currentIndex = findNext(-1); |
| this.lastIndex = -1; |
| } |
| |
| |
| /** |
| * Determines the index of the next header. |
| * |
| * @param from one less than the index to consider first, |
| * -1 to search for the first header |
| * |
| * @return the index of the next header that matches the filter name, |
| * or negative if there are no more headers |
| */ |
| protected int findNext(int from) { |
| if (from < -1) |
| return -1; |
| |
| final int to = this.allHeaders.size()-1; |
| boolean found = false; |
| while (!found && (from < to)) { |
| from++; |
| found = filterHeader(from); |
| } |
| return found ? from : -1; |
| } |
| |
| |
| /** |
| * Checks whether a header is part of the iteration. |
| * |
| * @param index the index of the header to check |
| * |
| * @return <code>true</code> if the header should be part of the |
| * iteration, <code>false</code> to skip |
| */ |
| protected boolean filterHeader(int index) { |
| if (this.headerName == null) |
| return true; |
| |
| // non-header elements, including null, will trigger exceptions |
| final String name = ((Header)this.allHeaders.get(index)).getName(); |
| |
| return this.headerName.equalsIgnoreCase(name); |
| } |
| |
| |
| // non-javadoc, see interface HeaderIterator |
| public boolean hasNext() { |
| return (this.currentIndex >= 0); |
| } |
| |
| |
| /** |
| * Obtains the next header from this iteration. |
| * |
| * @return the next header in this iteration |
| * |
| * @throws NoSuchElementException if there are no more headers |
| */ |
| public Header nextHeader() |
| throws NoSuchElementException { |
| |
| final int current = this.currentIndex; |
| if (current < 0) { |
| throw new NoSuchElementException("Iteration already finished."); |
| } |
| |
| this.lastIndex = current; |
| this.currentIndex = findNext(current); |
| |
| return (Header) this.allHeaders.get(current); |
| } |
| |
| |
| /** |
| * Returns the next header. |
| * Same as {@link #nextHeader nextHeader}, but not type-safe. |
| * |
| * @return the next header in this iteration |
| * |
| * @throws NoSuchElementException if there are no more headers |
| */ |
| public final Object next() |
| throws NoSuchElementException { |
| return nextHeader(); |
| } |
| |
| |
| /** |
| * Removes the header that was returned last. |
| */ |
| public void remove() |
| throws UnsupportedOperationException { |
| |
| if (this.lastIndex < 0) { |
| throw new IllegalStateException("No header to remove."); |
| } |
| this.allHeaders.remove(this.lastIndex); |
| this.lastIndex = -1; |
| this.currentIndex--; // adjust for the removed element |
| } |
| } |