Create simple utility for property map I/O

This helper reads and writes maps to/from plain text files, storing
entries in "key=value" pairs.

src/main/java/org/scijava/util/PropertiesHelper.java

@@ -0,0 +1,72 @@
+/*-
+ * #%L
+ * SciJava Common shared library for SciJava software.
+ * %%
+ * Copyright (C) 2009 - 2024 SciJava developers.
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+
+package org.scijava.util;
+
+import java.io.*;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Simple utility for reading and writing a property map to/from plain text.
+ */
+public final class PropertiesHelper {
+
+	public static Map<String, String> get(File filename) {
+		Map<String, String> map = new HashMap<>();
+		try (BufferedReader reader = new BufferedReader(new FileReader(filename))) {
+			String line;
+			while ((line = reader.readLine()) != null) {
+				String[] parts = line.split("=", 2);
+				if (parts.length == 2) {
+					map.put(parts[0], parts[1]);
+				}
+			}
+		}
+		catch (FileNotFoundException e) {
+			throw new RuntimeException(e);
+		}
+		catch (IOException e) {
+			throw new RuntimeException(e);
+		}
+		return map;
+	}
+
+	public static void put(Map<String, String> properties, File filename) {
+		try (BufferedWriter writer = new BufferedWriter(new FileWriter(filename))) {
+			for (Map.Entry<String, String> entry : properties.entrySet()) {
+				writer.write(entry.getKey() + "=" + entry.getValue());
+				writer.newLine();
+			}
+		}
+		catch (IOException e) {
+			throw new RuntimeException(e);
+		}
+	}
+}

src/test/java/org/scijava/util/PropertiesHelperTest.java

@@ -0,0 +1,138 @@
+/*-
+ * #%L
+ * SciJava Common shared library for SciJava software.
+ * %%
+ * Copyright (C) 2009 - 2024 SciJava developers.
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+
+package org.scijava.util;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.*;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Tests for {@link PropertiesHelper}
+ */
+public class PropertiesHelperTest {
+
+	private static final String EXPECTED_1 = "a=b";
+	private static final String EXPECTED_2 = "hello=goodbye";
+
+	private Map<String, String> props;
+	private File temp;
+
+	@Before
+	public void setup() throws IOException {
+		temp = File.createTempFile("PropertiesHelper", "txt");
+		props = new HashMap<>();
+		props.put("a", "b");
+		props.put("hello", "goodbye");
+	}
+
+	@After
+	public void cleanup() {
+		temp.delete();
+	}
+
+	@Test
+	public void testWrite() throws IOException {
+		PropertiesHelper.put(props, temp);
+
+		int count = 0;
+		boolean saw1 = false, saw2 = false;
+
+		try (BufferedReader reader = new BufferedReader(new FileReader(temp))) {
+			String line;
+			while ((line = reader.readLine()) != null) {
+				if (line.equals(EXPECTED_1)) {
+					saw1 = true;
+				}
+				if (line.equals(EXPECTED_2)) {
+					saw2 = true;
+				}
+				count++;
+			}
+		}
+		assertTrue(saw1);
+		assertTrue(saw2);
+		assertEquals(2, count);
+	}
+
+	@Test
+	public void testRead() throws IOException {
+		try (BufferedWriter writer = new BufferedWriter(new FileWriter(temp))) {
+			writer.write(EXPECTED_1);
+			writer.newLine();
+			writer.write(EXPECTED_2);
+			writer.newLine();
+		}
+
+		Map<String, String> propsMap = PropertiesHelper.get(temp);
+		assertTrue(props.equals(propsMap));
+	}
+
+	@Test
+	public void testIO() throws IOException {
+		PropertiesHelper.put(props, temp);
+		Map<String, String> propsMap = PropertiesHelper.get(temp);
+		assertTrue(props.equals(propsMap));
+	}
+
+	@Test
+	public void testMultipleEquals() throws IOException {
+		props.clear();
+		final String K = "hello", V = "world=true";
+		props.put(K, V);
+		PropertiesHelper.put(props, temp);
+		Map<String, String> propsMap = PropertiesHelper.get(temp);
+		assertEquals(1, propsMap.size());
+		assertEquals(props.get(K), propsMap.get(K));
+	}
+
+	@Test
+	public void testOverwrite() throws IOException {
+		PropertiesHelper.put(props, temp);
+		props.put("myname", "jonas");
+		PropertiesHelper.put(props, temp);
+		Map<String, String> loadedProps = PropertiesHelper.get(temp);
+		assertEquals(3, loadedProps.size());
+		int count = 0;
+		try (BufferedReader reader = new BufferedReader(new FileReader(temp))) {
+			String line;
+			while ((line = reader.readLine()) != null) {
+				count++;
+			}
+		}
+		assertEquals(3, count);
+	}
+}