Klasse FileLoader um Textdateien zu laden

src/main/java/schule/ngb/zm/util/FileLoader.java

@@ -0,0 +1,88 @@
+package schule.ngb.zm.util;
+
+import java.io.*;
+import java.net.URISyntaxException;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+public final class FileLoader {
+
+	public static final Charset ASCII = StandardCharsets.US_ASCII;
+
+	public static final Charset UTF8 = StandardCharsets.UTF_8;
+
+	public static final Charset UTF16 = StandardCharsets.UTF_16;
+
+	public static final Charset ISO_8859_1 = StandardCharsets.ISO_8859_1;
+
+
+	public static List<String> loadLines( String source ) {
+		return loadLines(source, UTF8);
+	}
+
+	public static List<String> loadLines( String source, Charset charset ) {
+		try {
+			return Files.readAllLines(Paths.get(ResourceStreamProvider.getResourceURL(source).toURI()), charset);
+		} catch( IOException | URISyntaxException ex ) {
+			LOG.warn(ex, "Error while loading lines from source <%s>", source);
+		}
+
+		return Collections.EMPTY_LIST;
+	}
+
+	public static String loadText( String source ) {
+		return loadText(source, UTF8);
+	}
+
+	public static String loadText( String source, Charset charset ) {
+		try {
+			return Files.readString(Paths.get(ResourceStreamProvider.getResourceURL(source).toURI()), charset);
+		} catch( IOException | URISyntaxException ex ) {
+			LOG.warn(ex, "Error while loading text from source <%s>", source);
+		}
+
+		return "";
+	}
+
+	public static double[][] loadDoubles( String source, char separator, boolean skipFirst ) {
+		return loadDoubles(source, separator, skipFirst, UTF8);
+	}
+
+	public static double[][] loadDoubles( String source, char separator, boolean skipFirst, Charset charset ) {
+		try {
+			int n = skipFirst ? 1 : 0;
+			return Files
+				.lines(Paths.get(ResourceStreamProvider.getResourceURL(source).toURI()), charset)
+				.skip(n)
+				.map(
+					(line) -> Arrays
+						.stream(line.split(Character.toString(separator)))
+						.mapToDouble(
+							(value) -> {
+								try {
+									return Double.parseDouble(value);
+								} catch( NumberFormatException nfe ) {
+									return 0.0;
+								}
+							}
+						).toArray()
+				).toArray(double[][]::new);
+		} catch( IOException | URISyntaxException ex ) {
+			LOG.warn(ex, "Error while loading double values from csv source <%s>", source);
+		}
+
+		return new double[0][0];
+	}
+
+	public FileLoader() {
+	}
+
+	private static final Log LOG = Log.getLogger(FileLoader.class);
+
+}

src/main/java/schule/ngb/zm/util/ImageLoader.java

@@ -17,7 +17,7 @@ import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Logger;
 
-public class ImageLoader {
+public final class ImageLoader {
 
 	public static boolean caching = true;
 

src/test/java/schule/ngb/zm/util/FileLoaderTest.java

@@ -0,0 +1,81 @@
+package schule.ngb.zm.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class FileLoaderTest {
+
+	@Test
+	void loadLines() {
+		String[] data;
+		List<String> lines;
+
+		data = new String[]{
+			"Header1,Header2,Header3",
+			"1.1,1.2,1.3",
+			"2.1,2.2,2.3",
+			"3.1,3.2,3.3"
+		};
+
+		lines = FileLoader.loadLines("data_comma.csv");
+		assertEquals(data.length, lines.size());
+		for( int i = 0; i < lines.size(); i++ ) {
+			assertEquals(data[i], lines.get(i));
+		}
+
+		data = new String[]{
+			"Nöme;Häder2;Straße",
+			"1.1;1.2;1.3",
+			"2.1;2.2;2.3",
+			"3.1;3.2;3.3"
+		};
+
+		lines = FileLoader.loadLines("data_semicolon_latin.csv", FileLoader.ISO_8859_1);
+		assertEquals(data.length, lines.size());
+		for( int i = 0; i < lines.size(); i++ ) {
+			assertEquals(data[i], lines.get(i));
+		}
+	}
+
+	@Test
+	void loadText() {
+		String data;
+		String text;
+
+		data = "Header1,Header2,Header3\n" +
+			"1.1,1.2,1.3\n" +
+			"2.1,2.2,2.3\n" +
+			"3.1,3.2,3.3\n";
+		text = FileLoader.loadText("data_comma.csv");
+		assertEquals(data, text);
+
+		data = "Nöme;Häder2;Straße\n" +
+			"1.1;1.2;1.3\n" +
+			"2.1;2.2;2.3\n" +
+			"3.1;3.2;3.3\n";
+		text = FileLoader.loadText("data_semicolon_latin.csv", FileLoader.ISO_8859_1);
+		assertEquals(data, text);
+	}
+
+	@Test
+	void loadCsv() {
+		double[][] data;
+		double[][] csv;
+
+		data = new double[][]{
+			{1.1,1.2,1.3},
+			{2.1,2.2,2.3},
+			{3.1,3.2,3.3}
+		};
+		csv = FileLoader.loadDoubles("data_comma.csv", ',', true);
+		assertArrayEquals(data, csv);
+
+		csv = FileLoader.loadDoubles("data_semicolon_latin.csv", ';', true, FileLoader.ISO_8859_1);
+		assertArrayEquals(data, csv);
+	}
+
+}

src/test/resources/data_comma.csv

@@ -0,0 +1,4 @@
+Header1,Header2,Header3
+1.1,1.2,1.3
+2.1,2.2,2.3
+3.1,3.2,3.3

src/test/resources/data_semicolon.csv

@@ -0,0 +1,4 @@
+Header1;Header2;Header3
+1.1;1.2;1.3
+2.1;2.2;2.3
+3.1;3.2;3.3

src/test/resources/data_semicolon_latin.csv

@@ -0,0 +1,4 @@
+Nöme;Häder2;Straße
+1.1;1.2;1.3
+2.1;2.2;2.3
+3.1;3.2;3.3