Null extensions + int/char/long extensions (#14)

kotlin-utils/build.gradle.kts

@@ -6,7 +6,7 @@ plugins {
 }
 
 group = "xyz.lbres"
-version = "0.2.1"
+version = "0.3.0"
 
 repositories {
     mavenCentral()

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/char/ext/CharExt.kt

@@ -0,0 +1,19 @@
+package xyz.lbres.kotlinutils.char.ext
+
+import xyz.lbres.kotlinutils.general.ternaryIf
+import xyz.lbres.kotlinutils.int.ext.isZero
+
+/**
+ * Returns this number if not zero, or the result of calling [getDefaultValue] if it is.
+ *
+ * @param getDefaultValue () -> [Char]
+ * @return [Char] the current value, or the default
+ */
+fun Char.ifZero(getDefaultValue: () -> Char): Char = ternaryIf(isZero(), getDefaultValue(), this)
+
+/**
+ * Unary check to determine if value is zero
+ *
+ * @return [Boolean]: true if value is zero, false otherwise
+ */
+fun Char.isZero(): Boolean = code.isZero()

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/collection/char/ext/CharCollectionExt.kt

@@ -0,0 +1,30 @@
+package xyz.lbres.kotlinutils.collection.char.ext
+
+import xyz.lbres.kotlinutils.char.ext.isZero
+
+/**
+ * Filter a char collection to contain only elements that do not equal zero.
+ *
+ * @return [Collection]<[Char]>: collection containing the same values as [this], except any elements with value 0.
+ */
+fun Collection<Char>.filterNotZero(): Collection<Char> = filterNot { it.isZero() }
+
+/**
+ * Add all values in collection.
+ *
+ * @return [Char]: sum of numbers in collection
+ */
+fun Collection<Char>.sum(): Char = fold(Char(0)) { acc, char -> acc + char.code }
+
+/**
+ * Multiply all values in collection
+ *
+ * @return [Char]: product of numbers in collection, or 0 if collection is empty
+ */
+fun Collection<Char>.product(): Char {
+    if (isEmpty()) {
+        return Char(0)
+    }
+
+    return fold(1) { acc, char -> acc * char.code }.toChar()
+}

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/collection/ext/CollectionExt.kt

@@ -4,7 +4,8 @@ import xyz.lbres.kotlinutils.classes.multiset.MultiSet
 import xyz.lbres.kotlinutils.classes.multiset.MultiSetImpl
 import xyz.lbres.kotlinutils.classes.multiset.MutableMultiSet
 import xyz.lbres.kotlinutils.classes.multiset.MutableMultiSetImpl
-import xyz.lbres.kotlinutils.int.ext.isZero
+import xyz.lbres.kotlinutils.generic.ext.isNotNull
+import xyz.lbres.kotlinutils.generic.ext.isNull
 
 /**
  * Create a MultiSet with the elements in the current collection.
@@ -21,8 +22,23 @@ fun <E> Collection<E>.toMultiSet(): MultiSet<E> = MultiSetImpl(this)
 fun <E> Collection<E>.toMutableMultiSet(): MutableMultiSet<E> = MutableMultiSetImpl(this)
 
 /**
- * Filter an integer collection to contain only elements that do not equal zero.
+ * Count number of elements in the collection that are null.
  *
- * @return [Collection<Int>]: collection containing the same values as [this], except any elements with value 0.
+ * @return [Int]
  */
-fun Collection<Int>.filterNotZero() = filterNot { it.isZero() }
+fun <E> Collection<E?>.countNull(): Int = count { it.isNull() }
+
+/**
+ * Count number of elements in the collection that are not null.
+ *
+ * @return [Int]
+ */
+fun <E> Collection<E?>.countNotNull(): Int = count { it.isNotNull() }
+
+/**
+ * Check if a collection is not null and is not empty.
+ * Combines separate calls for checking if the collection is null and if it is empty.
+ *
+ * @return [Boolean]: true if the collection is not null and has size > 0, false otherwise
+ */
+fun <E> Collection<E>?.isNotNullOrEmpty() = !this.isNullOrEmpty()

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/collection/int/ext/IntCollectionExt.kt

@@ -0,0 +1,25 @@
+package xyz.lbres.kotlinutils.collection.int.ext
+
+import xyz.lbres.kotlinutils.general.ternaryIf
+import xyz.lbres.kotlinutils.int.ext.isZero
+
+/**
+ * Filter an integer collection to contain only elements that do not equal zero.
+ *
+ * @return [Collection]<[Int]>: collection containing the same values as [this], except any elements with value 0.
+ */
+fun Collection<Int>.filterNotZero(): Collection<Int> = filterNot { it.isZero() }
+
+/**
+ * Add all values in collection.
+ *
+ * @return [Int]: sum of numbers in collection
+ */
+fun Collection<Int>.sum(): Int = fold(0, Int::plus)
+
+/**
+ * Multiply all values in collection
+ *
+ * @return [Int]: product of numbers in collection, or 0 if collection is empty
+ */
+fun Collection<Int>.product(): Int = ternaryIf(isEmpty(), 0, fold(1, Int::times))

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/collection/long/ext/LongCollectionExt.kt

@@ -0,0 +1,25 @@
+package xyz.lbres.kotlinutils.collection.long.ext
+
+import xyz.lbres.kotlinutils.general.ternaryIf
+import xyz.lbres.kotlinutils.long.ext.isZero
+
+/**
+ * Filter a long collection to contain only elements that do not equal zero.
+ *
+ * @return [Collection]<[Long]>: collection containing the same values as [this], except any elements with value 0.
+ */
+fun Collection<Long>.filterNotZero(): Collection<Long> = filterNot { it.isZero() }
+
+/**
+ * Add all values in collection.
+ *
+ * @return [Long]: sum of numbers in collection
+ */
+fun Collection<Long>.sum(): Long = fold(0, Long::plus)
+
+/**
+ * Multiply all values in collection
+ *
+ * @return [Long]: product of numbers in collection, or 0 if collection is empty
+ */
+fun Collection<Long>.product(): Long = ternaryIf(isEmpty(), 0, fold(1, Long::times))

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/generic/ext/GenericExt.kt

@@ -7,3 +7,17 @@ package xyz.lbres.kotlinutils.generic.ext
  * @return [T] the current value, or the default
  */
 fun <T> T?.ifNull(getDefaultValue: () -> T): T = this ?: getDefaultValue()
+
+/**
+ * Returns true if a value is null, or false otherwise
+ *
+ * @return [Boolean]
+ */
+fun <T> T?.isNull(): Boolean = this == null
+
+/**
+ * Returns true if a value is not null, or false otherwise
+ *
+ * @return [Boolean]
+ */
+fun <T> T?.isNotNull(): Boolean = this != null

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/int/ext/IntExt.kt

@@ -1,18 +1,14 @@
 package xyz.lbres.kotlinutils.int.ext
 
+import xyz.lbres.kotlinutils.general.ternaryIf
+
 /**
  * Returns this number if not zero, or the result of calling [getDefaultValue] if it is.
  *
- * @param getDefaultValue [() -> Int]
+ * @param getDefaultValue () -> [Int]
  * @return [Int] the current value, or the default
  */
-fun Int.ifZero(getDefaultValue: () -> Int): Int {
-    return if (equals(0)) {
-        getDefaultValue()
-    } else {
-        this
-    }
-}
+fun Int.ifZero(getDefaultValue: () -> Int): Int = ternaryIf(isZero(), getDefaultValue(), this)
 
 /**
  * Unary check to determine if value is zero

kotlin-utils/src/main/kotlin/xyz/lbres/kotlinutils/long/ext/LongExt.kt

@@ -0,0 +1,25 @@
+package xyz.lbres.kotlinutils.long.ext
+
+import xyz.lbres.kotlinutils.general.ternaryIf
+
+/**
+ * Returns this number if not zero, or the result of calling [getDefaultValue] if it is.
+ *
+ * @param getDefaultValue () -> [Long]
+ * @return [Long] the current value, or the default
+ */
+fun Long.ifZero(getDefaultValue: () -> Long): Long = ternaryIf(isZero(), getDefaultValue(), this)
+
+/**
+ * Unary check to determine if value is zero
+ *
+ * @return [Boolean]: true if value is zero, false otherwise
+ */
+fun Long.isZero(): Boolean = equals(0L)
+
+/**
+ * Unary check to determine if value is negative
+ *
+ * @return [Boolean]: true if value is less than zero, false otherwise
+ */
+fun Long.isNegative(): Boolean = this < 0L

kotlin-utils/src/test/kotlin/xyz/lbres/kotlinutils/char/ext/CharExtTest.kt

@@ -0,0 +1,37 @@
+package xyz.lbres.kotlinutils.char.ext
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+internal class CharExtTest {
+    @Test
+    internal fun testIfZero() {
+        val getValue = { Char(2) }
+
+        var char = Char(0)
+        var expected = Char(2)
+        assertEquals(expected, char.ifZero(getValue))
+
+        char = Char(2)
+        expected = Char(2)
+        assertEquals(expected, char.ifZero(getValue))
+
+        char = Char(15)
+        expected = Char(15)
+        assertEquals(expected, char.ifZero(getValue))
+    }
+
+    @Test
+    internal fun testIsZero() {
+        var char = Char(0)
+        assertTrue(char.isZero())
+
+        char = Char(1)
+        assertFalse(char.isZero())
+
+        char = Char(100)
+        assertFalse(char.isZero())
+    }
+}

kotlin-utils/src/test/kotlin/xyz/lbres/kotlinutils/collection/char/ext/CharCollectionExtTest.kt

@@ -0,0 +1,68 @@
+package xyz.lbres.kotlinutils.collection.char.ext
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+internal class CharCollectionExtTest {
+    private val zero = Char(0)
+    private val one = Char(1)
+    private val four = Char(4)
+    private val five = Char(5)
+
+    @Test
+    internal fun testFilterNotZero() {
+        var list: List<Char> = listOf()
+        var expected: List<Char> = listOf()
+        assertEquals(expected, list.filterNotZero())
+
+        list = listOf(zero, zero, zero)
+        expected = listOf()
+        assertEquals(expected, list.filterNotZero())
+
+        list = listOf(one, Char(2), zero, four, zero, zero, five)
+        expected = listOf(one, Char(2), four, five)
+        assertEquals(expected, list.filterNotZero())
+
+        list = listOf(one, four, Char(1000), Char(19), five)
+        expected = listOf(one, four, Char(1000), Char(19), five)
+        assertEquals(expected, list.filterNotZero())
+    }
+
+    @Test
+    internal fun testSum() {
+        var list: List<Char> = emptyList()
+        var expected = zero
+        assertEquals(expected, list.sum())
+
+        list = listOf(Char(33))
+        expected = Char(33)
+        assertEquals(expected, list.sum())
+
+        list = listOf(Char(100), Char(45), Char(10), Char(67), Char(99))
+        expected = Char(321)
+        assertEquals(expected, list.sum())
+    }
+
+    @Test
+    internal fun testProduct() {
+        var list: List<Char> = emptyList()
+        var expected = zero
+        assertEquals(expected, list.product())
+
+        list = listOf(zero)
+        expected = zero
+        assertEquals(expected, list.product())
+
+        list = listOf(one)
+        expected = one
+        assertEquals(expected, list.product())
+
+        list = listOf(four, four, zero)
+        expected = zero
+        assertEquals(expected, list.product())
+
+        list = listOf(Char(15), Char(23), Char(4), Char(4))
+        expected = Char(5520)
+        assertEquals(expected, list.product())
+    }
+}