| /* |
| * 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.IOException; |
| import java.io.Writer; |
| |
| /*** |
| * DotTerminatedMessageWriter is a class used to write messages to a |
| * server that are terminated by a single dot followed by a |
| * <CR><LF> |
| * sequence and with double dots appearing at the begining of lines which |
| * do not signal end of message yet start with a dot. Various Internet |
| * protocols such as NNTP and POP3 produce messages of this type. |
| * <p> |
| * This class handles the doubling of line-starting periods, |
| * converts single linefeeds to NETASCII newlines, and on closing |
| * will send the final message terminator dot and NETASCII newline |
| * sequence. |
| * |
| * |
| ***/ |
| |
| public final class DotTerminatedMessageWriter extends Writer |
| { |
| private static final int __NOTHING_SPECIAL_STATE = 0; |
| private static final int __LAST_WAS_CR_STATE = 1; |
| private static final int __LAST_WAS_NL_STATE = 2; |
| |
| private int __state; |
| private Writer __output; |
| |
| |
| /*** |
| * Creates a DotTerminatedMessageWriter that wraps an existing Writer |
| * output destination. |
| * |
| * @param output The Writer output destination to write the message. |
| ***/ |
| public DotTerminatedMessageWriter(Writer output) |
| { |
| super(output); |
| __output = output; |
| __state = __NOTHING_SPECIAL_STATE; |
| } |
| |
| |
| /*** |
| * Writes a character to the output. Note that a call to this method |
| * may result in multiple writes to the underling Writer in order to |
| * convert naked linefeeds to NETASCII line separators and to double |
| * line-leading periods. This is transparent to the programmer and |
| * is only mentioned for completeness. |
| * |
| * @param ch The character to write. |
| * @throws IOException If an error occurs while writing to the |
| * underlying output. |
| ***/ |
| @Override |
| public void write(int ch) throws IOException |
| { |
| synchronized (lock) |
| { |
| switch (ch) |
| { |
| case '\r': |
| __state = __LAST_WAS_CR_STATE; |
| __output.write('\r'); |
| return ; |
| case '\n': |
| if (__state != __LAST_WAS_CR_STATE) { |
| __output.write('\r'); |
| } |
| __output.write('\n'); |
| __state = __LAST_WAS_NL_STATE; |
| return ; |
| case '.': |
| // Double the dot at the beginning of a line |
| if (__state == __LAST_WAS_NL_STATE) { |
| __output.write('.'); |
| } |
| //$FALL-THROUGH$ |
| default: |
| __state = __NOTHING_SPECIAL_STATE; |
| __output.write(ch); |
| return ; |
| } |
| } |
| } |
| |
| |
| /*** |
| * Writes a number of characters from a character array to the output |
| * starting from a given offset. |
| * |
| * @param buffer The character array to write. |
| * @param offset The offset into the array at which to start copying data. |
| * @param length The number of characters to write. |
| * @throws IOException If an error occurs while writing to the underlying |
| * output. |
| ***/ |
| @Override |
| public void write(char[] buffer, int offset, int length) throws IOException |
| { |
| synchronized (lock) |
| { |
| while (length-- > 0) { |
| write(buffer[offset++]); |
| } |
| } |
| } |
| |
| |
| /*** |
| * Writes a character array to the output. |
| * |
| * @param buffer The character array to write. |
| * @throws IOException If an error occurs while writing to the underlying |
| * output. |
| ***/ |
| @Override |
| public void write(char[] buffer) throws IOException |
| { |
| write(buffer, 0, buffer.length); |
| } |
| |
| |
| /*** |
| * Writes a String to the output. |
| * |
| * @param string The String to write. |
| * @throws IOException If an error occurs while writing to the underlying |
| * output. |
| ***/ |
| @Override |
| public void write(String string) throws IOException |
| { |
| write(string.toCharArray()); |
| } |
| |
| |
| /*** |
| * Writes part of a String to the output starting from a given offset. |
| * |
| * @param string The String to write. |
| * @param offset The offset into the String at which to start copying data. |
| * @param length The number of characters to write. |
| * @throws IOException If an error occurs while writing to the underlying |
| * output. |
| ***/ |
| @Override |
| public void write(String string, int offset, int length) throws IOException |
| { |
| write(string.toCharArray(), offset, length); |
| } |
| |
| |
| /*** |
| * Flushes the underlying output, writing all buffered output. |
| * |
| * @throws IOException If an error occurs while writing to the underlying |
| * output. |
| ***/ |
| @Override |
| public void flush() throws IOException |
| { |
| synchronized (lock) |
| { |
| __output.flush(); |
| } |
| } |
| |
| |
| /*** |
| * Flushes the underlying output, writing all buffered output, but doesn't |
| * actually close the underlying stream. The underlying stream may still |
| * be used for communicating with the server and therefore is not closed. |
| * |
| * @throws IOException If an error occurs while writing to the underlying |
| * output or closing the Writer. |
| ***/ |
| @Override |
| public void close() throws IOException |
| { |
| synchronized (lock) |
| { |
| if (__output == null) { |
| return ; |
| } |
| |
| if (__state == __LAST_WAS_CR_STATE) { |
| __output.write('\n'); |
| } else if (__state != __LAST_WAS_NL_STATE) { |
| __output.write("\r\n"); |
| } |
| |
| __output.write(".\r\n"); |
| |
| __output.flush(); |
| __output = null; |
| } |
| } |
| |
| } |