X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=src%2Ftim%2Fprune%2Fload%2FFileCacher.java;fp=src%2Ftim%2Fprune%2Fload%2FFileCacher.java;h=a151c2e285022f48c5ffe8bbdf2c3d8433c09df0;hp=0000000000000000000000000000000000000000;hb=ce6f2161b8596f7018d6a76bff79bc9e571f35fd;hpb=2d8cb72e84d5cc1089ce77baf1e34ea3ea2f8465

diff --git a/src/tim/prune/load/FileCacher.java b/src/tim/prune/load/FileCacher.java
new file mode 100644
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--- /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;
+	}
+}