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Diffstat (limited to 'src/org/apache/http/message/BasicListHeaderIterator.java')
-rw-r--r-- | src/org/apache/http/message/BasicListHeaderIterator.java | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/src/org/apache/http/message/BasicListHeaderIterator.java b/src/org/apache/http/message/BasicListHeaderIterator.java new file mode 100644 index 0000000..69b8c06 --- /dev/null +++ b/src/org/apache/http/message/BasicListHeaderIterator.java @@ -0,0 +1,196 @@ +/* + * $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 + } +} |