Commons Net example source code file (ReplyIterator.java)

This example Commons Net source code file (ReplyIterator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Net tags/keywords

bufferedreader, dotterminatedmessagereader, exception, io, ioexception, ioexception, iterable, iterator, iterator, nosuchelementexception, replyiterator, replyiterator, string, string, unsupportedoperationexception, util

The Commons Net ReplyIterator.java source code

/*
 * 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.
 *
 */

package org.apache.commons.net.nntp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.Iterator;
import java.util.NoSuchElementException;

import org.apache.commons.net.io.DotTerminatedMessageReader;
import org.apache.commons.net.io.Util;

/**
 * Wraps a {@link Reader} and returns an {@code Iterable<String>}
 * which returns the individual lines from the reader.
 * @since 3.0
 */
class ReplyIterator implements Iterator<String>, Iterable {

    private final BufferedReader reader;

    private String line;

    private Exception savedException;

    /**
     *
     * @param _reader the reader to wrap
     * @param addDotReader whether to additionally wrap the reader in a DotTerminatedMessageReader
     * @throws IOException
     */
    ReplyIterator(BufferedReader _reader, boolean addDotReader) throws IOException {
        reader = addDotReader ? new DotTerminatedMessageReader(_reader) : _reader;
        line = reader.readLine(); // prime the iterator
        if (line == null) {
            Util.closeQuietly(reader);
        }
    }

    ReplyIterator(BufferedReader _reader) throws IOException {
        this(_reader, true);
    }

    public boolean hasNext() {
        if (savedException != null){
            throw new NoSuchElementException(savedException.toString());
        }
        return line != null;
    }

    public String next() throws NoSuchElementException {
        if (savedException != null){
            throw new NoSuchElementException(savedException.toString());
        }
        String prev = line;
        if (prev == null) {
            throw new NoSuchElementException();
        }
        try {
            line = reader.readLine(); // save next line
            if (line == null) {
                Util.closeQuietly(reader);
            }
        } catch (IOException ex) {
            savedException = ex; // if it fails, save the exception, as it does not apply to this call
            Util.closeQuietly(reader);
        }
        return prev;
    }

    public void remove() {
        throw new UnsupportedOperationException();
    }

    public Iterator<String> iterator() {
        return this;
    }
}