core/src/main/java/org/onap/aaf/cadi/BufferedServletInputStream.java

   1 /*******************************************************************************\r
   2  * ============LICENSE_START====================================================\r
   3  * * org.onap.aaf\r
   4  * * ===========================================================================\r
   5  * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.\r
   6  * * ===========================================================================\r
   7  * * Licensed under the Apache License, Version 2.0 (the "License");\r
   8  * * you may not use this file except in compliance with the License.\r
   9  * * You may obtain a copy of the License at\r
  10  * * \r
  11  *  *      http://www.apache.org/licenses/LICENSE-2.0\r
  12  * * \r
  13  *  * Unless required by applicable law or agreed to in writing, software\r
  14  * * distributed under the License is distributed on an "AS IS" BASIS,\r
  15  * * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
  16  * * See the License for the specific language governing permissions and\r
  17  * * limitations under the License.\r
  18  * * ============LICENSE_END====================================================\r
  19  * *\r
  20  * * ECOMP is a trademark and service mark of AT&T Intellectual Property.\r
  21  * *\r
  22  ******************************************************************************/\r
  23 package org.onap.aaf.cadi;\r
  24 \r
  25 import java.io.IOException;\r
  26 import java.io.InputStream;\r
  27 \r
  28 import javax.servlet.ServletInputStream;\r
  29 \r
  30 /**\r
  31  * BufferedServletInputStream\r
  32  * \r
  33  * There are cases in brain-dead middleware (SOAP) where they store routing information in the content.\r
  34  * \r
  35  * In HTTP, this requires reading the content from the InputStream which, of course, cannot be re-read.\r
  36  * \r
  37  * BufferedInputStream exists to implement the "Mark" protocols for Streaming, which will enable being \r
  38  * re-read.  Unfortunately, J2EE chose to require a "ServletInputStream" as an abstract class, rather than\r
  39  * an interface, which requires we create a delegating pattern, rather than the preferred inheriting pattern. \r
  40  * \r
  41  * Unfortunately, the standard "BufferedInputStream" cannot be used, because it simply creates a byte array\r
  42  * in the "mark(int)" method of that size.  This is not appropriate for this application, because the Header \r
  43  * can be potentially huge, and if a buffer was allocated to accommodate all possibilities, the cost of memory \r
  44  * allocation would be too large for high performance transactions.\r
  45  *\r
  46  * \r
  47  *\r
  48  */\r
  49 public class BufferedServletInputStream extends ServletInputStream {\r
  50         private static final int NONE = 0;\r
  51         private static final int STORE = 1;\r
  52         private static final int READ = 2;\r
  53         \r
  54         private InputStream is;\r
  55         private int state = NONE;\r
  56         private Capacitor capacitor;\r
  57 \r
  58         public BufferedServletInputStream(InputStream is) {\r
  59                 this.is = is;\r
  60                 capacitor = null;\r
  61         }\r
  62 \r
  63 \r
  64         // @Override\r
  65         public int read() throws IOException {\r
  66                 int value=-1;\r
  67                 if(capacitor==null) {\r
  68                         value=is.read();\r
  69                 } else {\r
  70                         switch(state) {\r
  71                                 case STORE:\r
  72                                         value = is.read();\r
  73                                         if(value>=0) {\r
  74                                                 capacitor.put((byte)value);\r
  75                                         }\r
  76                                         break;\r
  77                                 case READ:\r
  78                                         value = capacitor.read();\r
  79                                         if(value<0) {\r
  80                                                 capacitor.done();\r
  81                                                 capacitor=null; // all done with buffer\r
  82                                                 value = is.read();\r
  83                                         }\r
  84                         }\r
  85                 } \r
  86                 return value;\r
  87         }\r
  88 \r
  89         // @Override\r
  90         public int read(byte[] b) throws IOException {\r
  91                 return read(b,0,b.length);\r
  92         }\r
  93 \r
  94 \r
  95         // @Override\r
  96         public int read(byte[] b, int off, int len) throws IOException {\r
  97                 int count = -1;\r
  98                 if(capacitor==null) {\r
  99                         count = is.read(b,off,len);\r
 100                 } else {\r
 101                         switch(state) {\r
 102                                 case STORE:\r
 103                                         count = is.read(b, off, len);\r
 104                                         if(count>0) {\r
 105                                                 capacitor.put(b, off, count);\r
 106                                         }\r
 107                                         break;\r
 108                                 case READ:\r
 109                                         count = capacitor.read(b, off, len);\r
 110 //                                      System.out.println("Capacitor read " + count);\r
 111                                         if(count<=0) {\r
 112                                                 capacitor.done();\r
 113                                                 capacitor=null; // all done with buffer\r
 114                                         }\r
 115                                         if(count<len) {\r
 116                                                 int temp = is.read(b, count, len-count);\r
 117 //                                              System.out.println("Capacitor done, stream read " + temp);\r
 118                                                 if(temp>0) { // watch for -1\r
 119                                                         count+=temp;\r
 120                                                 } else {\r
 121                                                         if(count<=0)count = temp; // must account for Stream coming back -1  \r
 122                                                 }\r
 123                                         }\r
 124                                         break;\r
 125                         }\r
 126                 }\r
 127 //              System.out.println("read reports " + count);\r
 128                 return count;\r
 129         }\r
 130 \r
 131         // @Override\r
 132         public long skip(long n) throws IOException {\r
 133                 long skipped = capacitor.skip(n);\r
 134                 if(skipped<n) {\r
 135                         skipped += is.skip(n-skipped);\r
 136                 }\r
 137                 return skipped;\r
 138         }\r
 139 \r
 140 \r
 141         // @Override\r
 142         public int available() throws IOException {\r
 143                 int count = is.available();\r
 144                 if(capacitor!=null)count+=capacitor.available();\r
 145                 return count;           \r
 146         }\r
 147         \r
 148         /**\r
 149          * Return just amount buffered (for debugging purposes, mostly)\r
 150          * @return\r
 151          */\r
 152         public int buffered() {\r
 153                 return capacitor.available();\r
 154         }\r
 155 \r
 156 \r
 157         // @Override\r
 158         public void close() throws IOException {\r
 159                 if(capacitor!=null) {\r
 160                         capacitor.done();\r
 161                         capacitor=null;\r
 162                 }\r
 163                 is.close();\r
 164         }\r
 165 \r
 166 \r
 167         /**\r
 168          * Note: Readlimit is ignored in this implementation, because the need was for unknown buffer size which wouldn't \r
 169          * require allocating and dumping huge chunks of memory every use, or risk overflow.\r
 170          */\r
 171         // @Override\r
 172         public synchronized void mark(int readlimit) {\r
 173                 switch(state) {\r
 174                         case NONE:\r
 175                                 capacitor = new Capacitor();\r
 176                                 break;\r
 177                         case READ:\r
 178                                 capacitor.done();\r
 179                                 break;\r
 180                         // ignore case STORE:\r
 181                 }\r
 182                 state = STORE;\r
 183         }\r
 184 \r
 185 \r
 186         /**\r
 187          * Reset Stream\r
 188          * \r
 189          * Calling this twice is not supported in typical Stream situations, but it is allowed in this service.  The caveat is that it can only reset\r
 190          * the data read in since Mark has been called.  The data integrity is only valid if you have not continued to read past what is stored.\r
 191          *  \r
 192          */\r
 193         // @Override\r
 194         public synchronized void reset() throws IOException {\r
 195                 switch(state) {\r
 196                         case STORE:\r
 197                                 capacitor.setForRead();\r
 198                                 state = READ;\r
 199                                 break;\r
 200                         case READ:\r
 201                                 capacitor.reset();\r
 202                                 break;\r
 203 //                              throw new IOException("InputStream is already in READ state");\r
 204                         case NONE: \r
 205                                 throw new IOException("InputStream has not been marked");\r
 206                 }\r
 207         }\r
 208 \r
 209 \r
 210         // @Override\r
 211         public boolean markSupported() {\r
 212                 return true;\r
 213         }\r
 214 }\r