Add a new offlinefileslist function

src/fileOfflineData/OfflineFileList.java

@@ -0,0 +1,88 @@
+package fileOfflineData;
+
+import java.io.File;
+import java.io.FileFilter;
+import java.util.ArrayList;
+
+/**
+ * Make a list of files with the given file filter. 
+ * @author dg50
+ *
+ */
+public class OfflineFileList {
+	
+	private ArrayList<File> files = new ArrayList<>();
+	private String folder;
+	private FileFilter fileFilter;
+	private boolean includeSubFolders;
+
+	public OfflineFileList(String folder, FileFilter fileFilter, boolean includeSubFolders) {
+		this.folder = folder;
+		this.fileFilter = fileFilter;
+		this.includeSubFolders = includeSubFolders;
+		updateCatalog();
+	}
+	
+	public int updateCatalog() {
+		files.clear();
+		File current = new File(this.folder);
+		addFiles(current);
+		return files.size();
+	}
+
+	private void addFiles(File current) {
+		if (current.exists() == false) {
+			return;
+		}
+		if (current.isFile() && checkFilter(current)) {
+			/*
+			 * This can only really happen if the root passed in is a file, not a 
+			 * folder, since files within the folder structure will get 
+			 * added from the loop below. 
+			 */
+			files.add(current);
+		}
+		else if (current.isDirectory()) {
+			File[] filesList = current.listFiles();
+			if (filesList == null) {
+				return;
+			}
+			for (int i = 0; i < filesList.length; i++) {
+				File aFile = filesList[i];
+				if (aFile.isFile() && checkFilter(aFile)) {
+					files.add(aFile);
+				}
+				else if (aFile.isDirectory() && includeSubFolders) {
+					addFiles(aFile);
+				}
+			}
+		}
+	}
+
+	/**
+	 * Check that if there is a filter, the file is accepted. 
+	 * @param aFile
+	 * @return
+	 */
+	private boolean checkFilter(File aFile) {
+		if (fileFilter == null) {
+			return true;
+		}
+		return fileFilter.accept(aFile);
+	}
+
+	/**
+	 * Get a list of files in the catalog as a simple string list. 
+	 * @return files as strings
+	 */
+	public String[] asStringList() {
+		if (files == null) {
+			return null;
+		}
+		String[] str = new String[files.size()];
+		for (int i = 0; i < files.size(); i++) {
+			str[i] = files.get(i).getAbsolutePath();
+		}
+		return str;
+	}
+}