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/*
 * ====================================================================
 * 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
 * .
 *
 */

package cz.msebera.android.httpclient.message;

import java.util.List;
import java.util.NoSuchElementException;

import cz.msebera.android.httpclient.Header;
import cz.msebera.android.httpclient.HeaderIterator;
import cz.msebera.android.httpclient.annotation.NotThreadSafe;
import cz.msebera.android.httpclient.util.Args;
import cz.msebera.android.httpclient.util.Asserts;

/**
 * Implementation of a {@link HeaderIterator} based on a {@link List}.
 * For use by {@link HeaderGroup}.
 *
 * @since 4.0
 */
@NotThreadSafe
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. * null 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 * null for any */ public BasicListHeaderIterator(final List
headers, final String name) { super(); this.allHeaders = Args.notNull(headers, "Header list"); this.headerName = name; this.currentIndex = findNext(-1); this.lastIndex = -1; } /** * Determines the index of the next header. * * @param pos 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(final int pos) { int from = pos; 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 true if the header should be part of the * iteration, false to skip */ protected boolean filterHeader(final int index) { if (this.headerName == null) { return true; } // non-header elements, including null, will trigger exceptions final String name = (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 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 { Asserts.check(this.lastIndex >= 0, "No header to remove"); this.allHeaders.remove(this.lastIndex); this.lastIndex = -1; this.currentIndex--; // adjust for the removed element } }




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