CRLFLineReader.java
- /*
- * 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;
- import org.apache.commons.net.util.NetConstants;
- /**
- * 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(final 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 {
- final StringBuilder sb = new StringBuilder();
- int intch;
- boolean prevWasCR = false;
- synchronized (lock) { // make thread-safe (hopefully!)
- while ((intch = read()) != NetConstants.EOS) {
- if (prevWasCR && intch == LF) {
- return sb.substring(0, sb.length() - 1);
- }
- prevWasCR = intch == CR;
- sb.append((char) intch);
- }
- }
- final String string = sb.toString();
- if (string.isEmpty()) { // immediate EOF
- return null;
- }
- return string;
- }
- }