Provide Java implementation to list available icons

src/main/java/io/jenkins/plugins/ionicons/Ionicons.java

@@ -0,0 +1,77 @@
+package io.jenkins.plugins.ionicons;
+
+import java.io.File;
+import java.net.URL;
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.Map;
+import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang.StringUtils;
+
+/**
+ * Utility to work with icons provided by the ionicons-api-plugin.
+ * 
+ * @author strangelookingnerd
+ *
+ */
+public final class Ionicons {
+
+    private static final Logger LOGGER = Logger.getLogger(Ionicons.class.getName());
+
+    private static final String[] SVG_FILE_FORMAT = { "svg" };
+    private static final String SVG_FILE_ENDING = "." + SVG_FILE_FORMAT[0];
+    private static final String IMAGES_SYMBOLS_PATH = "images/symbols/";
+    private static final String IONICONS_API_PLUGIN = "ionicons-api-plugin";
+    private static final String ICON_CLASS_NAME_PATTERN = "symbol-%s plugin-ionicons-api";
+
+    private static final Ionicons INSTANCE = new Ionicons();
+
+    private final Map<String, String> availableIcons = new ConcurrentSkipListMap<>();
+
+    private Ionicons() {
+	try {
+	    Enumeration<URL> urls = getClass().getClassLoader().getResources(IMAGES_SYMBOLS_PATH);
+
+	    while (urls.hasMoreElements()) {
+		URL url = urls.nextElement();
+
+		if (StringUtils.contains(url.toExternalForm(), IONICONS_API_PLUGIN)) {
+		    Collection<File> icons = FileUtils.listFiles(new File(url.toURI()), SVG_FILE_FORMAT, false);
+
+		    for (File icon : icons) {
+			String iconName = StringUtils.removeEnd(icon.getName(), SVG_FILE_ENDING);
+			availableIcons.put(iconName, getIconClassName(iconName));
+		    }
+		    break;
+		}
+	    }
+	} catch (Exception ex) {
+	    LOGGER.log(Level.WARNING, "Unable to read available icons: Resource unavailable.", ex);
+	}
+    }
+
+    /**
+     * Takes an icon name and generates a icon class name from it.
+     * 
+     * @param icon the icon name
+     * @return the icon class name
+     */
+    public static String getIconClassName(String icon) {
+	return String.format(ICON_CLASS_NAME_PATTERN, icon);
+    }
+
+    /**
+     * Get all available icons provided by the ionicons-api-plugin.
+     * 
+     * @return a sorted map of available icons with icon name as key and the icon
+     *         class name as value.
+     */
+    public static Map<String, String> getAvailableIcons() {
+	return INSTANCE.availableIcons;
+    }
+
+}

src/test/java/io/jenkins/plugins/ionicons/IoniconsTest.java

@@ -0,0 +1,53 @@
+package io.jenkins.plugins.ionicons;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.io.File;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang.StringUtils;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test Class for {@link Ionicons}.
+ * 
+ * @author strangelookingnerd
+ *
+ */
+class IoniconsTest {
+
+    @Test
+    void testGetIconClassName() {
+	assertEquals("symbol-test plugin-ionicons-api", Ionicons.getIconClassName("test"));
+    }
+
+    @Test
+    void testGetAvailableIcons() {
+	Map<String, String> availableIcons = Ionicons.getAvailableIcons();
+
+	assertNotNull(availableIcons);
+	assertFalse(availableIcons.isEmpty());
+
+	Collection<File> icons = FileUtils.listFiles(new File("./src/main/resources/images/symbols/"),
+		new String[] { "svg" }, false);
+	assertEquals(icons.size(), availableIcons.size());
+
+	List<String> iconNames = icons.stream().map(icon -> StringUtils.removeEnd(icon.getName(), ".svg"))
+		.sorted(Comparator.naturalOrder()).collect(Collectors.toList());
+	assertIterableEquals(iconNames, availableIcons.keySet());
+
+	for (Entry<String, String> icon : availableIcons.entrySet()) {
+	    assertEquals(icon.getValue(), Ionicons.getIconClassName(icon.getKey()));
+	}
+    }
+
+}