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Commons Net example source code file (CRLFLineReader.java)

This example Commons Net source code file (CRLFLineReader.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, cr, cr, crlflinereader, crlflinereader, eof, io, ioexception, lf, override, string, string, stringbuilder, stringbuilder

The Commons Net CRLFLineReader.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.io;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;

/**
 * CRLFLineReader implements a readLine() method that requires
 * exactly CRLF to terminate an input line.
 * This is required for IMAP, which allows bare CR and LF.
 *
 * @since 3.0
 */
public final class CRLFLineReader extends BufferedReader
{
    private static final char LF = '\n';
    private static final char CR = '\r';

    /**
     * Creates a CRLFLineReader that wraps an existing Reader
     * input source.
     * @param reader  The Reader input source.
     */
    public CRLFLineReader(Reader reader)
    {
        super(reader);
    }

    /**
     * Read a line of text.
     * A line is considered to be terminated by carriage return followed immediately by a linefeed.
     * This contrasts with BufferedReader which also allows other combinations.
     * @since 3.0
     */
    @Override
    public String readLine() throws IOException {
        StringBuilder sb = new StringBuilder();
        int intch;
        boolean prevWasCR = false;
        synchronized(lock) { // make thread-safe (hopefully!)
            while((intch = read()) != -1)
            {
                if (prevWasCR && intch == LF) {
                    return sb.substring(0, sb.length()-1);
                }
                if (intch == CR) {
                    prevWasCR = true;
                } else {
                    prevWasCR = false;
                }
                sb.append((char) intch);
            }
        }
        String string = sb.toString();
        if (string.length() == 0) { // immediate EOF
            return null;
        }
        return string;
    }
}

Other Commons Net examples (source code examples)

Here is a short list of links related to this Commons Net CRLFLineReader.java source code file:

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