001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019 020 // 021 // This source code implements specifications defined by the Java 022 // Community Process. In order to remain compliant with the specification 023 // DO NOT add / change / or delete method signatures! 024 // 025 026 package javax.servlet; 027 028 import java.io.IOException; 029 import java.io.InputStream; 030 031 /** 032 * 033 * Provides an input stream for reading binary data from a client 034 * request, including an efficient <code>readLine</code> method 035 * for reading data one line at a time. With some protocols, such 036 * as HTTP POST and PUT, a <code>ServletInputStream</code> 037 * object can be used to read data sent from the client. 038 * 039 * <p>A <code>ServletInputStream</code> object is normally retrieved via 040 * the {@link ServletRequest#getInputStream} method. 041 * 042 * <p>This is an abstract class that a servlet container implements. 043 * Subclasses of this class 044 * must implement the <code>java.io.InputStream.read()</code> method. 045 * 046 * @see ServletRequest 047 * 048 * @version $Rev: 467553 $ $Date: 2006-10-25 06:01:51 +0200 (Mi, 25. Okt 2006) $ 049 */ 050 public abstract class ServletInputStream extends InputStream { 051 /** 052 * Does nothing, because this is an abstract class. 053 */ 054 protected ServletInputStream() { 055 } 056 057 /** 058 * Reads the input stream, one line at a time. Starting at an 059 * offset, reads bytes into an array, until it reads a certain number 060 * of bytes or reaches a newline character, which it reads into the 061 * array as well. 062 * 063 * <p>This method returns -1 if it reaches the end of the input 064 * stream before reading the maximum number of bytes. 065 * 066 * @param b an array of bytes into which data is read 067 * 068 * @param off an integer specifying the character at which 069 * this method begins reading 070 * 071 * @param len an integer specifying the maximum number of 072 * bytes to read 073 * 074 * @return an integer specifying the actual number of bytes 075 * read, or -1 if the end of the stream is reached 076 * 077 * @exception IOException if an input or output exception has occurred 078 */ 079 public int readLine(byte[] b, int off, int len) throws IOException { 080 if (len <= 0) { 081 return 0; 082 } 083 int count = 0, c; 084 085 while ((c = read()) != -1) { 086 b[off++] = (byte) c; 087 count++; 088 if (c == '\n' || count == len) { 089 break; 090 } 091 } 092 return count > 0 ? count : -1; 093 } 094 } 095 096 097