Iss1051 data transfer

haas-imagej-client/src/main/java/cz/it4i/fiji/haas/data_transfer/PersistentIndex.java

+package cz.it4i.fiji.haas.data_transfer;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.LinkedHashSet;
+import java.util.Queue;
+import java.util.Set;
+import java.util.function.Function;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class PersistentIndex<T> {
+	
+	public static final Logger log = LoggerFactory.getLogger(cz.it4i.fiji.haas.data_transfer.PersistentIndex.class);
+	
+	private final Path workingFile;
+
+	private final Set<T> files = new LinkedHashSet<>();
+
+	private final Function<String, T> fromString;
+
+	public PersistentIndex(Path workingFile,Function<String, T> fromString) throws IOException {
+		this.workingFile = workingFile;
+		this.fromString = fromString;
+		loadFromFile();
+	}
+
+	public synchronized void storeToFile() throws IOException {
+		try (BufferedWriter bw = Files.newBufferedWriter(workingFile)) {
+			for (T file : files) {
+				bw.write(file.toString() + "\n");
+			}
+		}
+	}
+
+	public synchronized boolean insert(T file) {
+		return files.add(file);
+	}
+
+	public synchronized void remove(T p) {
+		files.remove(p);
+	}
+
+	public synchronized void fillQueue(Queue<T> toUpload) {
+		toUpload.addAll(files);
+	}
+	
+	public synchronized void clear() throws IOException {
+		files.clear();
+		storeToFile();
+	}
+
+	public synchronized boolean contains(Path file) {
+		return files.contains(file);
+	}
+
+	private void loadFromFile() throws IOException {
+		files.clear();
+		if(Files.exists(workingFile)) {
+			try (BufferedReader br = Files.newBufferedReader(workingFile)) {
+				String line;
+				while (null != (line = br.readLine())) {
+					processLine(line);
+				}
+			}
+		}
+	}
+
+	private void processLine(String line) {
+		files.add(fromString.apply(line));
+	}
+
+	
+}