Update Collections.

Author: gk-brown

README.md

@@ -1028,15 +1028,18 @@ public static <K, V> Map<K, V> mapOf(Map.Entry<K, V>... entries) { ... }
 public static <E> Set<E> setOf(E... elements) { ... }
 ```
 
-They offer an alternative to similar methods defined by the `List`, `Map`, and `Set` interfaces, which produce immutable instances and do not permit `null` values. The following immutable variants are provided as well:
+They offer an alternative to similar methods defined by the `List`, `Map`, and `Set` interfaces, which produce immutable instances and do not permit `null` values. The following immutable and sorted variants are provided as well:
 
 ```java
 public static <E> List<E> immutableListOf(E... elements) { ... }
 public static <K, V> Map<K, V> immutableMapOf(Map.Entry<K, V>... entries) { ... }
 public static <E> Set<E> immutableSetOf(E... elements) { ... }
+
+public static <K extends Comparable<K>, V> SortedMap<K, V> sortedMapOf(Map.Entry<K, V>... entries) { ... }
+public static <E extends Comparable<E>> SortedSet<E> sortedSetOf(E... elements) { ... }
 ```
 
-This method can be used to declare entries for either `mapOf()` or `immutableMapOf()`:
+This method can be used to declare map entries:
 
 ```java
 public static <K, V> Map.Entry<K, V> entry(K key, V value) { ... }

build.gradle

@@ -14,7 +14,7 @@
 
 subprojects {
     group = 'org.httprpc'
-    version = '5.3'
+    version = '5.3.1'
 
     repositories {
         mavenCentral()

kilo-client/src/main/java/org/httprpc/kilo/util/Collections.java

@@ -21,6 +21,10 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.SortedMap;
+import java.util.SortedSet;
+import java.util.TreeMap;
+import java.util.TreeSet;
 
 /**
  * Provides static utility methods for working with collections.
@@ -115,6 +119,32 @@ public static <K, V> Map<K, V> immutableMapOf(Map.Entry<K, V>... entries) {
         return java.util.Collections.unmodifiableMap(mapOf(entries));
     }
 
+    /**
+     * Creates a sorted map of entries.
+     *
+     * @param <K>
+     * The key type.
+     *
+     * @param <V>
+     * The value type.
+     *
+     * @param entries
+     * The map entries.
+     *
+     * @return
+     * A map containing the provided entries sorted by key.
+     */
+    @SafeVarargs
+    public static <K extends Comparable<K>, V> SortedMap<K, V> sortedMapOf(Map.Entry<K, V>... entries) {
+        var map = new TreeMap<K, V>();
+
+        for (var entry : entries) {
+            map.put(entry.getKey(), entry.getValue());
+        }
+
+        return map;
+    }
+
     /**
      * Creates an immutable map entry.
      *
@@ -175,6 +205,27 @@ public static <E> Set<E> immutableSetOf(E... elements) {
         return java.util.Collections.unmodifiableSet(setOf(elements));
     }
 
+    /**
+     * Creates a sorted set of elements.
+     *
+     * @param <E>
+     * The element type.
+     *
+     * @param elements
+     * The set elements.
+     *
+     * @return
+     * A sorted set containing the provided elements.
+     */
+    @SafeVarargs
+    public static <E extends Comparable<E>> SortedSet<E> sortedSetOf(E... elements) {
+        var set = new TreeSet<E>();
+
+        java.util.Collections.addAll(set, elements);
+
+        return set;
+    }
+
     /**
      * Returns an empty list.
      *

kilo-client/src/test/java/org/httprpc/kilo/util/CollectionsTest.java

@@ -80,6 +80,17 @@ public void testImmutableMapOf() {
         assertThrows(UnsupportedOperationException.class, () -> map.put("d", 4));
     }
 
+    @Test
+    public void testSortedMapOf() {
+        var sortedMap = sortedMapOf(
+            entry("c", 3),
+            entry("b", 2),
+            entry("a", 1)
+        );
+
+        assertEquals(listOf(1, 2, 3), new ArrayList<>(sortedMap.values()));
+    }
+
     @Test
     public void testSetOf() {
         var expected = new HashSet<Integer>(3);
@@ -104,6 +115,14 @@ public void testImmutableSetOf() {
         assertThrows(UnsupportedOperationException.class, () -> set.add(4));
     }
 
+    @Test
+    public void testSortedSetOf() {
+        var sortedSet = sortedSetOf(3, 2, 1);
+
+        assertEquals(listOf(1, 2, 3), new ArrayList<>(sortedSet));
+
+    }
+
     @Test
     public void testEmptyListOf() {
         var list1 = java.util.Collections.<Integer>emptyList();