Coverage Report - org.apache.commons.io.input.ProxyInputStream
 
Classes in this File Line Coverage Branch Coverage Complexity
ProxyInputStream
70%
33/47
75%
3/4
2.154
 
 1  
 /*
 2  
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3  
  * contributor license agreements.  See the NOTICE file distributed with
 4  
  * this work for additional information regarding copyright ownership.
 5  
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6  
  * (the "License"); you may not use this file except in compliance with
 7  
  * the License.  You may obtain a copy of the License at
 8  
  *
 9  
  *      http://www.apache.org/licenses/LICENSE-2.0
 10  
  *
 11  
  * Unless required by applicable law or agreed to in writing, software
 12  
  * distributed under the License is distributed on an "AS IS" BASIS,
 13  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  
  * See the License for the specific language governing permissions and
 15  
  * limitations under the License.
 16  
  */
 17  
 package org.apache.commons.io.input;
 18  
 
 19  
 import java.io.FilterInputStream;
 20  
 import java.io.IOException;
 21  
 import java.io.InputStream;
 22  
 
 23  
 /**
 24  
  * A Proxy stream which acts as expected, that is it passes the method
 25  
  * calls on to the proxied stream and doesn't change which methods are
 26  
  * being called.
 27  
  * <p>
 28  
  * It is an alternative base class to FilterInputStream
 29  
  * to increase reusability, because FilterInputStream changes the
 30  
  * methods being called, such as read(byte[]) to read(byte[], int, int).
 31  
  * <p>
 32  
  * See the protected methods for ways in which a subclass can easily decorate
 33  
  * a stream with custom pre-, post- or error processing functionality.
 34  
  *
 35  
  * @version $Id: ProxyInputStream.java 1415850 2012-11-30 20:51:39Z ggregory $
 36  
  */
 37  
 public abstract class ProxyInputStream extends FilterInputStream {
 38  
 
 39  
     /**
 40  
      * Constructs a new ProxyInputStream.
 41  
      *
 42  
      * @param proxy  the InputStream to delegate to
 43  
      */
 44  
     public ProxyInputStream(final InputStream proxy) {
 45  1228
         super(proxy);
 46  
         // the proxy is stored in a protected superclass variable named 'in'
 47  1228
     }
 48  
 
 49  
     /**
 50  
      * Invokes the delegate's <code>read()</code> method.
 51  
      * @return the byte read or -1 if the end of stream
 52  
      * @throws IOException if an I/O error occurs
 53  
      */
 54  
     @Override
 55  
     public int read() throws IOException {
 56  
         try {
 57  56
             beforeRead(1);
 58  56
             final int b = in.read();
 59  54
             afterRead(b != -1 ? 1 : -1);
 60  54
             return b;
 61  2
         } catch (final IOException e) {
 62  2
             handleIOException(e);
 63  0
             return -1;
 64  
         }
 65  
     }
 66  
 
 67  
     /**
 68  
      * Invokes the delegate's <code>read(byte[])</code> method.
 69  
      * @param bts the buffer to read the bytes into
 70  
      * @return the number of bytes read or -1 if the end of stream
 71  
      * @throws IOException if an I/O error occurs
 72  
      */
 73  
     @Override
 74  
     public int read(final byte[] bts) throws IOException {
 75  
         try {
 76  2113632
             beforeRead(bts != null ? bts.length : 0);
 77  2113632
             final int n = in.read(bts);
 78  2113632
             afterRead(n);
 79  2113632
             return n;
 80  0
         } catch (final IOException e) {
 81  0
             handleIOException(e);
 82  0
             return -1;
 83  
         }
 84  
     }
 85  
 
 86  
     /**
 87  
      * Invokes the delegate's <code>read(byte[], int, int)</code> method.
 88  
      * @param bts the buffer to read the bytes into
 89  
      * @param off The start offset
 90  
      * @param len The number of bytes to read
 91  
      * @return the number of bytes read or -1 if the end of stream
 92  
      * @throws IOException if an I/O error occurs
 93  
      */
 94  
     @Override
 95  
     public int read(final byte[] bts, final int off, final int len) throws IOException {
 96  
         try {
 97  70
             beforeRead(len);
 98  70
             final int n = in.read(bts, off, len);
 99  70
             afterRead(n);
 100  70
             return n;
 101  0
         } catch (final IOException e) {
 102  0
             handleIOException(e);
 103  0
             return -1;
 104  
         }
 105  
     }
 106  
 
 107  
     /**
 108  
      * Invokes the delegate's <code>skip(long)</code> method.
 109  
      * @param ln the number of bytes to skip
 110  
      * @return the actual number of bytes skipped
 111  
      * @throws IOException if an I/O error occurs
 112  
      */
 113  
     @Override
 114  
     public long skip(final long ln) throws IOException {
 115  
         try {
 116  4
             return in.skip(ln);
 117  0
         } catch (final IOException e) {
 118  0
             handleIOException(e);
 119  0
             return 0;
 120  
         }
 121  
     }
 122  
 
 123  
     /**
 124  
      * Invokes the delegate's <code>available()</code> method.
 125  
      * @return the number of available bytes
 126  
      * @throws IOException if an I/O error occurs
 127  
      */
 128  
     @Override
 129  
     public int available() throws IOException {
 130  
         try {
 131  104
             return super.available();
 132  2
         } catch (final IOException e) {
 133  2
             handleIOException(e);
 134  0
             return 0;
 135  
         }
 136  
     }
 137  
 
 138  
     /**
 139  
      * Invokes the delegate's <code>close()</code> method.
 140  
      * @throws IOException if an I/O error occurs
 141  
      */
 142  
     @Override
 143  
     public void close() throws IOException {
 144  
         try {
 145  754
             in.close();
 146  2
         } catch (final IOException e) {
 147  2
             handleIOException(e);
 148  752
         }
 149  752
     }
 150  
 
 151  
     /**
 152  
      * Invokes the delegate's <code>mark(int)</code> method.
 153  
      * @param readlimit read ahead limit
 154  
      */
 155  
     @Override
 156  
     public synchronized void mark(final int readlimit) {
 157  2
         in.mark(readlimit);
 158  2
     }
 159  
 
 160  
     /**
 161  
      * Invokes the delegate's <code>reset()</code> method.
 162  
      * @throws IOException if an I/O error occurs
 163  
      */
 164  
     @Override
 165  
     public synchronized void reset() throws IOException {
 166  
         try {
 167  2
             in.reset();
 168  0
         } catch (final IOException e) {
 169  0
             handleIOException(e);
 170  2
         }
 171  2
     }
 172  
 
 173  
     /**
 174  
      * Invokes the delegate's <code>markSupported()</code> method.
 175  
      * @return true if mark is supported, otherwise false
 176  
      */
 177  
     @Override
 178  
     public boolean markSupported() {
 179  8
         return in.markSupported();
 180  
     }
 181  
 
 182  
     /**
 183  
      * Invoked by the read methods before the call is proxied. The number
 184  
      * of bytes that the caller wanted to read (1 for the {@link #read()}
 185  
      * method, buffer length for {@link #read(byte[])}, etc.) is given as
 186  
      * an argument.
 187  
      * <p>
 188  
      * Subclasses can override this method to add common pre-processing
 189  
      * functionality without having to override all the read methods.
 190  
      * The default implementation does nothing.
 191  
      * <p>
 192  
      * Note this method is <em>not</em> called from {@link #skip(long)} or
 193  
      * {@link #reset()}. You need to explicitly override those methods if
 194  
      * you want to add pre-processing steps also to them.
 195  
      *
 196  
      * @since 2.0
 197  
      * @param n number of bytes that the caller asked to be read
 198  
      * @throws IOException if the pre-processing fails
 199  
      */
 200  
     protected void beforeRead(final int n) throws IOException {
 201  2113758
     }
 202  
 
 203  
     /**
 204  
      * Invoked by the read methods after the proxied call has returned
 205  
      * successfully. The number of bytes returned to the caller (or -1 if
 206  
      * the end of stream was reached) is given as an argument.
 207  
      * <p>
 208  
      * Subclasses can override this method to add common post-processing
 209  
      * functionality without having to override all the read methods.
 210  
      * The default implementation does nothing.
 211  
      * <p>
 212  
      * Note this method is <em>not</em> called from {@link #skip(long)} or
 213  
      * {@link #reset()}. You need to explicitly override those methods if
 214  
      * you want to add post-processing steps also to them.
 215  
      *
 216  
      * @since 2.0
 217  
      * @param n number of bytes read, or -1 if the end of stream was reached
 218  
      * @throws IOException if the post-processing fails
 219  
      */
 220  
     protected void afterRead(final int n) throws IOException {
 221  16548
     }
 222  
 
 223  
     /**
 224  
      * Handle any IOExceptions thrown.
 225  
      * <p>
 226  
      * This method provides a point to implement custom exception
 227  
      * handling. The default behaviour is to re-throw the exception.
 228  
      * @param e The IOException thrown
 229  
      * @throws IOException if an I/O error occurs
 230  
      * @since 2.0
 231  
      */
 232  
     protected void handleIOException(final IOException e) throws IOException {
 233  0
         throw e;
 234  
     }
 235  
 
 236  
 }