src/main/java/eu/svjatoslav/meviz/htmlindexer/metadata/fileTypes/AbstractFile.java

   1 package eu.svjatoslav.meviz.htmlindexer.metadata.fileTypes;
   2
   3 import java.io.File;
   4 import java.io.IOException;
   5 import java.io.Serializable;
   6
   7 import eu.svjatoslav.commons.file.FilePathParser;
   8
   9 public abstract class AbstractFile implements Serializable {
  10
  11         private static final long serialVersionUID = -2547388204667088033L;
  12
  13         /**
  14          * File name relative to the immediate parent directory.
  15          */
  16         public final String fileName;
  17
  18         /**
  19          * File length in bytes.
  20          */
  21         private long fileLength = -1;
  22
  23         private transient boolean metaInfoVerified;
  24
  25         public AbstractFile(final File parentDirectory, final String fileName)
  26                         throws Exception {
  27                 this.fileName = fileName;
  28                 ensureFileMetainfoIsUpToDate(parentDirectory);
  29         }
  30
  31         /**
  32          * @return <code>true</code> if file metadata was updated.
  33          */
  34         public boolean ensureFileMetainfoIsUpToDate(final File parentDirectory)
  35                         throws Exception {
  36                 if (!isMetainfoUpToDate(parentDirectory)) {
  37                         fileLength = getFile(parentDirectory).length();
  38                         updateFileMetainfo(parentDirectory);
  39                         metaInfoVerified = true;
  40                         return true;
  41                 }
  42                 return false;
  43         };
  44
  45         public boolean fileExists(final File parentDirectory) {
  46                 return getFile(parentDirectory).exists();
  47         }
  48
  49         public File getFile(final File parentDirectory) {
  50                 return new File(parentDirectory.getAbsolutePath(), fileName);
  51         }
  52
  53         public String getFileExtension() {
  54                 return FilePathParser.getFileExtension(fileName);
  55         }
  56
  57         public long getFileLength() {
  58                 return fileLength;
  59         }
  60
  61         private boolean isMetainfoUpToDate(final java.io.File parentDirectory)
  62                         throws IOException {
  63
  64                 if (metaInfoVerified)
  65                         return true;
  66
  67                 final File file = getFile(parentDirectory);
  68
  69                 // first check that file exists at all
  70                 if (!file.exists()) {
  71                         System.out.println(file);
  72                         throw new RuntimeException("Picture file by name \"" + fileName
  73                                         + "\" does not exist in the parent directory \""
  74                                         + parentDirectory.getAbsolutePath() + "\"");
  75                 }
  76
  77                 // check that file length is the same as before
  78                 if (file.length() != fileLength)
  79                         return false;
  80
  81                 metaInfoVerified = true;
  82                 return true;
  83         }
  84
  85         public boolean isMetaInfoVerified() {
  86                 return metaInfoVerified;
  87         }
  88
  89         protected abstract void updateFileMetainfo(final File parentDirectory)
  90                         throws Exception;
  91
  92 }