fix: raise exception in generic

Author: proost

src/main/java/org/apache/datasketches/quantilescommon/GenericSortedView.java

@@ -67,7 +67,7 @@ public interface GenericSortedView<T>  extends PartitioningFeature<T>, SketchPar
    * </blockquote>
    * @param searchCrit the desired search criteria.
    * @return a discrete CDF array of m+1 double ranks (or cumulative probabilities) on the interval [0.0, 1.0].
-   * @throws IllegalArgumentException if sketch is empty.
+   * @throws SketchesArgumentException if sketch is empty.
    */
   default double[] getCDF(final T[] splitPoints, final QuantileSearchCriteria searchCrit) {
     if (isEmpty()) { throw new SketchesArgumentException(EMPTY_MSG); }
@@ -92,7 +92,7 @@ default double[] getCDF(final T[] splitPoints, final QuantileSearchCriteria sear
    * sketch algorithm.
    *
    * @return the maximum item of the stream
-   * @throws IllegalArgumentException if sketch is empty.
+   * @throws SketchesArgumentException if sketch is empty.
    */
   T getMaxItem();
 
@@ -101,7 +101,7 @@ default double[] getCDF(final T[] splitPoints, final QuantileSearchCriteria sear
    * sketch algorithm.
    *
    * @return the minimum item of the stream
-   * @throws IllegalArgumentException if sketch is empty.
+   * @throws SketchesArgumentException if sketch is empty.
    */
   T getMinItem();
 
@@ -143,7 +143,7 @@ default double[] getCDF(final T[] splitPoints, final QuantileSearchCriteria sear
    * </blockquote>
    * @param searchCrit the desired search criteria.
    * @return a PMF array of m+1 probability masses as doubles on the interval [0.0, 1.0].
-   * @throws IllegalArgumentException if sketch is empty.
+   * @throws SketchesArgumentException if sketch is empty.
    */
   default double[] getPMF(final T[] splitPoints, final QuantileSearchCriteria searchCrit) {
     if (isEmpty()) { throw new SketchesArgumentException(EMPTY_MSG); }
@@ -164,7 +164,7 @@ default double[] getPMF(final T[] splitPoints, final QuantileSearchCriteria sear
    * If EXCLUSIVE, he given rank includes all quantiles &lt;
    * the quantile directly corresponding to the given rank.
    * @return the approximate quantile given the normalized rank.
-   * @throws IllegalArgumentException if sketch is empty.
+   * @throws SketchesArgumentException if sketch is empty.
    * @see org.apache.datasketches.quantilescommon.QuantileSearchCriteria
    */
   T getQuantile(double rank, QuantileSearchCriteria searchCrit);
@@ -181,7 +181,7 @@ default double[] getPMF(final T[] splitPoints, final QuantileSearchCriteria sear
    * @param quantile the given quantile
    * @param searchCrit if INCLUSIVE the given quantile is included into the rank.
    * @return the normalized rank corresponding to the given quantile.
-   * @throws IllegalArgumentException if sketch is empty.
+   * @throws SketchesArgumentException if sketch is empty.
    * @see org.apache.datasketches.quantilescommon.QuantileSearchCriteria
    */
   double getRank(T quantile, QuantileSearchCriteria searchCrit);

src/main/java/org/apache/datasketches/quantilescommon/ItemsSketchSortedView.java

@@ -104,12 +104,14 @@ public long[] getCumulativeWeights() {
 
   @Override
   public T getMaxItem() {
+    if (isEmpty()) { throw new SketchesArgumentException(EMPTY_MSG); }
     final int top = quantiles.length - 1;
     return quantiles[top];
   }
 
   @Override
   public T getMinItem() {
+    if (isEmpty()) { throw new SketchesArgumentException(EMPTY_MSG); }
     return quantiles[0];
   }
 

src/test/java/org/apache/datasketches/quantilescommon/SortedViewEmptyAccessorTest.java

@@ -0,0 +1,95 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.datasketches.quantilescommon;
+
+import static org.testng.Assert.fail;
+
+import java.util.Comparator;
+
+import org.apache.datasketches.common.SketchesArgumentException;
+import org.testng.annotations.Test;
+
+public final class SortedViewEmptyAccessorTest {
+
+  @Test
+  public void checkFloatsSortedViewEmptyAccessors() {
+    final FloatsSketchSortedView sv = new FloatsSketchSortedView(
+        new float[] {1F},
+        new long[] {1},
+        0,
+        1F,
+        1F);
+
+    assertEmptyAccessorThrows(() -> sv.getMaxItem());
+    assertEmptyAccessorThrows(() -> sv.getMinItem());
+  }
+
+  @Test
+  public void checkDoublesSortedViewEmptyAccessors() {
+    final DoublesSketchSortedView sv = new DoublesSketchSortedView(
+        new double[] {1.0},
+        new long[] {1},
+        0,
+        1.0,
+        1.0);
+
+    assertEmptyAccessorThrows(() -> sv.getMaxItem());
+    assertEmptyAccessorThrows(() -> sv.getMinItem());
+  }
+
+  @Test
+  public void checkLongsSortedViewEmptyAccessors() {
+    final LongsSketchSortedView sv = new LongsSketchSortedView(
+        new long[] {1},
+        new long[] {1},
+        0,
+        1,
+        1);
+
+    assertEmptyAccessorThrows(() -> sv.getMaxItem());
+    assertEmptyAccessorThrows(() -> sv.getMinItem());
+  }
+
+  @Test
+  public void checkItemsSortedViewEmptyAccessors() {
+    final ItemsSketchSortedView<String> sv = new ItemsSketchSortedView<>(
+        new String[] {"1"},
+        new long[] {1},
+        0,
+        Comparator.naturalOrder(),
+        "1",
+        "1",
+        String.class,
+        .01,
+        1);
+
+    assertEmptyAccessorThrows(() -> sv.getMaxItem());
+    assertEmptyAccessorThrows(() -> sv.getMinItem());
+  }
+
+  private static void assertEmptyAccessorThrows(final Runnable accessor) {
+    try {
+      accessor.run();
+      fail();
+    } catch (final SketchesArgumentException e) {
+      // expected
+    }
+  }
+}