feat: Add incrementBy to FrequencyVectorBuilder (#1817)

src/main/kotlin/org/wfanet/measurement/eventdataprovider/shareshuffle/v2alpha/FrequencyVectorBuilder.kt

@@ -172,6 +172,17 @@ class FrequencyVectorBuilder(
    *   supported by this builder
    */
   fun increment(globalIndex: Int) {
+    incrementBy(globalIndex, 1)
+  }
+
+  /**
+   * Increment the frequency vector for the VID at globalIndex by amount.
+   *
+   * See [increment] for additional information.
+   */
+  fun incrementBy(globalIndex: Int, amount: Int) {
+    require(amount > 0) { "amount must be > 0 got ${amount}" }
+
     if (!(globalIndex in primaryRange || globalIndex in wrappedRange)) {
       if (strict) {
         require(globalIndex in primaryRange || globalIndex in wrappedRange) {
@@ -188,15 +199,23 @@ class FrequencyVectorBuilder(
       } else {
         primaryRange.count() + globalIndex
       }
-    frequencyData[localIndex] = minOf(frequencyData[localIndex] + 1, maxFrequency)
+    frequencyData[localIndex] = minOf(frequencyData[localIndex] + amount, maxFrequency)
   }
 
   /**
    * Add each globalIndex in the input Collection to the [FrequencyVector] according to the criteria
-   * described by [addVid]
+   * described by [increment]
    */
   fun incrementAll(globalIndexes: Collection<Int>) {
-    globalIndexes.map { increment(it) }
+    globalIndexes.map { incrementBy(it, 1) }
+  }
+
+  /**
+   * Add each globalIndex in the input Collection to the [FrequencyVector] according to the criteria
+   * described by [incrementBy]
+   */
+  fun incrementAllBy(globalIndexes: Collection<Int>, amount: Int) {
+    globalIndexes.map { incrementBy(it, amount) }
   }
 
   /**

src/test/kotlin/org/wfanet/measurement/eventdataprovider/shareshuffle/v2alpha/FrequencyVectorBuilderTest.kt

@@ -227,11 +227,18 @@ class FrequencyVectorBuilderTest {
     assertThat(builder.build()).isEqualTo(frequencyVector { data += listOf<Int>(0, 0, 0, 0, 0) })
   }
 
+  @Test
+  fun `incrementBy fails when amount is 0`() {
+    val builder =
+      FrequencyVectorBuilder(SMALL_POPULATION_SPEC, PARTIAL_NON_WRAPPING_REACH_MEASUREMENT_SPEC)
+    assertFailsWith<IllegalArgumentException>("expected exception") { builder.incrementBy(5, 0) }
+  }
+
   @Test
   fun `build returns a frequency vector for frequency over full interval`() {
     val frequencyMeasurementSpec = measurementSpec {
       vidSamplingInterval = FULL_SAMPLING_INTERVAL
-      reachAndFrequency = reachAndFrequency { maximumFrequency = 2 }
+      reachAndFrequency = reachAndFrequency { maximumFrequency = 3 }
     }
 
     val frequencyVector =
@@ -245,11 +252,11 @@ class FrequencyVectorBuilderTest {
             STARTING_VID + 8,
             STARTING_VID + 8,
           )
-          .map { increment(SMALL_POPULATION_VID_INDEX_MAP[it]) }
+          .map { incrementBy(SMALL_POPULATION_VID_INDEX_MAP[it], 2) }
       }
 
     assertThat(frequencyVector)
-      .isEqualTo(frequencyVector { data += listOf<Int>(2, 1, 0, 0, 0, 0, 0, 0, 2, 0) })
+      .isEqualTo(frequencyVector { data += listOf<Int>(3, 2, 0, 0, 0, 0, 0, 0, 3, 0) })
   }
 
   @Test