Java tutorial
/* * 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.finger; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.BufferedOutputStream; import java.io.DataOutputStream; import org.apache.commons.net.SocketClient; import org.apache.commons.net.util.Charsets; /*** * The FingerClient class implements the client side of the Internet Finger * Protocol defined in RFC 1288. To finger a host you create a * FingerClient instance, connect to the host, query the host, and finally * disconnect from the host. If the finger service you want to query is on * a non-standard port, connect to the host at that port. * Here's a sample use: * <pre> * FingerClient finger; * * finger = new FingerClient(); * * try { * finger.connect("foo.bar.com"); * System.out.println(finger.query("foobar", false)); * finger.disconnect(); * } catch(IOException e) { * System.err.println("Error I/O exception: " + e.getMessage()); * return; * } * </pre> * <p> * <p> ***/ public class FingerClient extends SocketClient { /*** * The default FINGER port. Set to 79 according to RFC 1288. ***/ public static final int DEFAULT_PORT = 79; private static final String __LONG_FLAG = "/W "; private transient char[] __buffer = new char[1024]; /*** * The default FingerClient constructor. Initializes the * default port to <code> DEFAULT_PORT </code>. ***/ public FingerClient() { setDefaultPort(DEFAULT_PORT); } /*** * Fingers a user at the connected host and returns the output * as a String. You must first connect to a finger server before * calling this method, and you should disconnect afterward. * <p> * @param longOutput Set to true if long output is requested, false if not. * @param username The name of the user to finger. * @return The result of the finger query. * @exception IOException If an I/O error occurs while reading the socket. ***/ public String query(boolean longOutput, String username) throws IOException { int read; StringBuilder result = new StringBuilder(__buffer.length); BufferedReader input; input = new BufferedReader(new InputStreamReader(getInputStream(longOutput, username), getCharsetName())); // Java 1.6 can use getCharset() try { while (true) { read = input.read(__buffer, 0, __buffer.length); if (read <= 0) { break; } result.append(__buffer, 0, read); } } finally { input.close(); } return result.toString(); } /*** * Fingers the connected host and returns the output * as a String. You must first connect to a finger server before * calling this method, and you should disconnect afterward. * This is equivalent to calling <code> query(longOutput, "") </code>. * <p> * @param longOutput Set to true if long output is requested, false if not. * @return The result of the finger query. * @exception IOException If an I/O error occurs while reading the socket. ***/ public String query(boolean longOutput) throws IOException { return query(longOutput, ""); } /*** * Fingers a user and returns the input stream from the network connection * of the finger query. You must first connect to a finger server before * calling this method, and you should disconnect after finishing reading * the stream. * <p> * @param longOutput Set to true if long output is requested, false if not. * @param username The name of the user to finger. * @return The InputStream of the network connection of the finger query. * Can be read to obtain finger results. * @exception IOException If an I/O error during the operation. ***/ public InputStream getInputStream(boolean longOutput, String username) throws IOException { return getInputStream(longOutput, username, null); } /*** * Fingers a user and returns the input stream from the network connection * of the finger query. You must first connect to a finger server before * calling this method, and you should disconnect after finishing reading * the stream. * <p> * @param longOutput Set to true if long output is requested, false if not. * @param username The name of the user to finger. * @param encoding the character encoding that should be used for the query, * null for the platform's default encoding * @return The InputStream of the network connection of the finger query. * Can be read to obtain finger results. * @exception IOException If an I/O error during the operation. ***/ public InputStream getInputStream(boolean longOutput, String username, String encoding) throws IOException { DataOutputStream output; StringBuilder buffer = new StringBuilder(64); if (longOutput) { buffer.append(__LONG_FLAG); } buffer.append(username); buffer.append(SocketClient.NETASCII_EOL); // Note: Charsets.toCharset() returns the platform default for null input byte[] encodedQuery = buffer.toString().getBytes(Charsets.toCharset(encoding).name()); // Java 1.6 can use charset directly output = new DataOutputStream(new BufferedOutputStream(_output_, 1024)); output.write(encodedQuery, 0, encodedQuery.length); output.flush(); return _input_; } /*** * Fingers the connected host and returns the input stream from * the network connection of the finger query. This is equivalent to * calling getInputStream(longOutput, ""). You must first connect to a * finger server before calling this method, and you should disconnect * after finishing reading the stream. * <p> * @param longOutput Set to true if long output is requested, false if not. * @return The InputStream of the network connection of the finger query. * Can be read to obtain finger results. * @exception IOException If an I/O error during the operation. ***/ public InputStream getInputStream(boolean longOutput) throws IOException { return getInputStream(longOutput, ""); } }