Moved source into separate src directory due to popular request

[GpsPrune.git] / src / tim / prune / load / FileCacher.java

diff --git a/src/tim/prune/load/FileCacher.java b/src/tim/prune/load/FileCacher.java
new file mode 100644 (file)
index 0000000..a151c2e
--- /dev/null
+++ b/src/tim/prune/load/FileCacher.java
@@ -0,0 +1,141 @@
+package tim.prune.load;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+
+/**
+ * Class to load the contents of a file
+ * into an array for later retrieval
+ */
+public class FileCacher
+{
+       /** File to cache */
+       private File _file = null;
+       /** Array to hold lines of file */
+       private String[] _contentArray = null;
+
+
+       /**
+        * Constructor
+        * @param inFile File object to cache
+        */
+       public FileCacher(File inFile)
+       {
+               _file = inFile;
+               loadFile();
+       }
+
+
+       /**
+        * Load the specified file into memory
+        */
+       private void loadFile()
+       {
+               ArrayList<String> contentList = new ArrayList<String>();
+               if (_file != null && _file.exists() && _file.canRead())
+               {
+                       BufferedReader reader = null;
+                       try
+                       {
+                               reader = new BufferedReader(new FileReader(_file));
+                               String currLine = reader.readLine();
+                               if (currLine != null && currLine.startsWith("<?xml")) {
+                                       return; // it's an xml file, it shouldn't use this cacher
+                               }
+                               while (currLine != null)
+                               {
+                                       if (currLine.indexOf('\0') >= 0)
+                                       {
+                                               reader.close();
+                                               return; // it's a binary file, shouldn't use this cacher
+                                       }
+                                       if (currLine.trim().length() > 0)
+                                               contentList.add(currLine);
+                                       currLine = reader.readLine();
+                               }
+                       }
+                       catch (IOException ioe) {}
+                       finally
+                       {
+                               // close file ignoring errors
+                               try
+                               {
+                                       if (reader != null) reader.close();
+                               }
+                               catch (Exception e) {}
+                       }
+               }
+               // Convert into String array for keeps
+               int numLines = contentList.size();
+               _contentArray = new String[numLines];
+               for (int i=0; i<numLines; i++)
+                       _contentArray[i] = contentList.get(i);
+       }
+
+
+       /**
+        * @return Contents of the file as array of non-blank Strings
+        */
+       public String[] getContents()
+       {
+               return _contentArray;
+       }
+
+
+       /**
+        * Get the top section of the file for preview
+        * @param inNumRows number of lines to extract
+        * @param inMaxWidth max length of Strings (longer ones will be chopped)
+        * @return String array containing non-blank lines from the file
+        */
+       public String[] getSnippet(int inNumRows, int inMaxWidth)
+       {
+               final int MIN_SNIPPET_SIZE = 3;
+               // Check size is within sensible limits
+               int numToCopy = inNumRows;
+               if (numToCopy > getNumLines()) numToCopy = getNumLines();
+               int size = numToCopy;
+               if (size < MIN_SNIPPET_SIZE) size = MIN_SNIPPET_SIZE;
+               String[] result = new String[size];
+               // Copy Strings across
+               System.arraycopy(_contentArray, 0, result, 0, numToCopy);
+               // Chop Strings to max width if necessary
+               if (inMaxWidth > 10)
+               {
+                       for (int i=0; i<size; i++)
+                       {
+                               if (result[i] == null)
+                                       result[i] = "";
+                               else
+                               {
+                                       if (result[i].length() > inMaxWidth)
+                                               result[i] = result[i].trim();
+                                       if (result[i].length() > inMaxWidth)
+                                               result[i] = result[i].substring(0, inMaxWidth);
+                               }
+                       }
+               }
+               return result;
+       }
+
+       /**
+        * @return the number of non-blank lines in the file
+        */
+       public int getNumLines()
+       {
+               return _contentArray.length;
+       }
+
+
+       /**
+        * Clear the memory
+        */
+       public void clear()
+       {
+               _file = null;
+               _contentArray = null;
+       }
+}