Improved javadocs for main code.

src/main/java/org/apache/datasketches/cpc/CompressionCharacterization.java

@@ -68,6 +68,18 @@ public class CompressionCharacterization {
   private CompressedState[] compressedStates2;
   private CpcSketch[] unCompressedSketches;
 
+  /**
+   * Only used in test.
+   * @param lgMinK min lgK
+   * @param lgMaxK max lgK
+   * @param lgMinT min lgTrials
+   * @param lgMaxT max lgTrials
+   * @param lgMulK lg multiple
+   * @param uPPO unique axis Points Per Octave
+   * @param incLgK increment lgK
+   * @param pS PrintStream
+   * @param pW PrintWriter
+   */
   @SuppressFBWarnings(value = "EI_EXPOSE_REP2", justification = "This is OK here")
   public CompressionCharacterization(
       final int lgMinK,
@@ -91,6 +103,9 @@ public CompressionCharacterization(
     assembleFormats();
   }
 
+  /**
+   * Only used in test
+   */
   public void start() {
     printf(hfmt, (Object[]) hStrArr); //print header
     doRangeOfLgK();

src/main/java/org/apache/datasketches/filters/bloomfilter/BloomFilter.java

@@ -54,10 +54,12 @@
  * false positive probability.</p>
  *
  * <p>This implementation uses xxHash64 and follows the approach in Kirsch and Mitzenmacher,
- * "Less Hashing, Same Performance: Building a Better Bloom Filter," Wiley Interscience, 2008,
- * pp. 187-218.</p>
+ * "Less Hashing, Same Performance: Building a Better Bloom Filter," Wiley Interscience, 2008, pp. 187-218.</p>
  */
 public final class BloomFilter {
+  /**
+   * The maximum size of a bloom filter in bits.
+   */
   public static final long MAX_SIZE_BITS = (Integer.MAX_VALUE - Family.BLOOMFILTER.getMaxPreLongs()) * (long) Long.SIZE;
   private static final int SER_VER = 1;
   private static final int EMPTY_FLAG_MASK = 4;
@@ -133,11 +135,23 @@ public static BloomFilter heapify(final Memory mem) {
     return internalHeapifyOrWrap((WritableMemory) mem, false, false);
   }
 
+  /**
+   * Wraps the given Memory into this filter class.  The class itself only contains a few metadata items and holds
+   * a reference to the Memory object, which contains all the data.
+   * @param mem the given Memory object
+   * @return the wrapping BloomFilter class.
+   */
   public static BloomFilter wrap(final Memory mem) {
     // casting to writable, but tracking that the object is read-only
     return internalHeapifyOrWrap((WritableMemory) mem, true, false);
   }
 
+  /**
+   * Wraps the given WritableMemory into this filter class.  The class itself only contains a few metadata items and holds
+   * a reference to the Memory object, which contains all the data.
+   * @param wmem the given WritableMemory object
+   * @return the wrapping BloomFilter class.
+   */
   public static BloomFilter writableWrap(final WritableMemory wmem) {
     return internalHeapifyOrWrap(wmem, true, true);
   }

src/main/java/org/apache/datasketches/filters/bloomfilter/DirectBitArrayR.java

@@ -24,6 +24,9 @@
 import org.apache.datasketches.memory.Memory;
 import org.apache.datasketches.memory.WritableMemory;
 
+/**
+ * This class can maintain the BitArray object off-heap.
+ */
 public class DirectBitArrayR extends BitArray {
   final static protected long NUM_BITS_OFFSET = Long.BYTES;
   final static protected long DATA_OFFSET = 2L * Long.BYTES;

src/main/java/org/apache/datasketches/hll/TgtHllType.java

@@ -50,10 +50,27 @@
  * </ul>
  * @author Lee Rhodes
  */
-public enum TgtHllType { HLL_4, HLL_6, HLL_8;
+public enum TgtHllType {
+  /**
+   * An HLL sketch with a bin size of 4 bits
+   */
+  HLL_4,
+  /**
+   * An HLL sketch with a bin size of 6 bits
+   */
+  HLL_6,
+  /**
+   * An Hll Sketch with a bin size of 8 bits
+   */
+  HLL_8;
 
   private static final TgtHllType values[] = values();
 
+  /**
+   * Convert the typeId to the enum type
+   * @param typeId the given typeId
+   * @return the enum type
+   */
   public static final TgtHllType fromOrdinal(final int typeId) {
     return values[typeId];
   }

src/main/java/org/apache/datasketches/kll/KllItemsSketch.java

@@ -290,6 +290,10 @@ public void reset() {
     itemsSV = null;
   }
 
+  /**
+   * Export the current sketch as a compact byte array.
+   * @return the current sketch as a compact byte array.
+   */
   public byte[] toByteArray() {
     return KllHelper.toByteArray(this, false);
   }

src/main/java/org/apache/datasketches/kll/KllItemsSketchIterator.java

@@ -23,6 +23,7 @@
 
 /**
  * Iterator over KllItemsSketch. The order is not defined.
+ * @param <T> the item class type
  */
 public final class KllItemsSketchIterator<T> extends KllSketchIterator implements QuantilesGenericSketchIterator<T> {
   private final Object[] quantiles;

src/main/java/org/apache/datasketches/kll/KllSketch.java

@@ -218,6 +218,10 @@ public boolean hasMemory() {
     return (wmem != null);
   }
 
+  /**
+   * Returns true if this sketch is in a Compact Memory Format.
+   * @return true if this sketch is in a Compact Memory Format.
+   */
   public boolean isCompactMemoryFormat() {
     return hasMemory() && sketchStructure != UPDATABLE;
   }
@@ -488,9 +492,18 @@ final void setLevelsArrayAt(final int index, final int idxVal) {
    * Used to define the variable type of the current instance of this class.
    */
   public enum SketchType {
-    DOUBLES_SKETCH(Double.BYTES, "DoublesSketch"),
-    FLOATS_SKETCH(Float.BYTES, "FloatsSketch"),
-    ITEMS_SKETCH(0, "ItemsSketch");
+    /**
+     * KllDoublesSketch
+     */
+    DOUBLES_SKETCH(Double.BYTES, "KllDoublesSketch"),
+    /**
+     * KllFloatsSketch
+     */
+    FLOATS_SKETCH(Float.BYTES, "KllFloatsSketch"),
+    /**
+     * KllItemsSketch
+     */
+    ITEMS_SKETCH(0, "KllItemsSketch");
 
     private int typeBytes;
     private String name;
@@ -500,18 +513,30 @@ private SketchType(final int typeBytes, final String name) {
       this.name = name;
     }
 
+    /**
+     * Gets the item size in bytes. If the item is generic, this returns zero.
+     * @return the item size in bytes
+     */
     public int getBytes() { return typeBytes; }
 
+    /**
+     * Get the name of the associated sketch
+     * @return the name of the associated sketch
+     */
     public String getName() { return name; }
   }
 
   /**
    * Used primarily to define the structure of the serialized sketch. Also used by the Heap Sketch.
    */
   public enum SketchStructure {
+    /** Compact Empty Structure */
     COMPACT_EMPTY(PREAMBLE_INTS_EMPTY_SINGLE, SERIAL_VERSION_EMPTY_FULL),
+    /** Compact Single Item Structure */
     COMPACT_SINGLE(PREAMBLE_INTS_EMPTY_SINGLE, SERIAL_VERSION_SINGLE),
+    /** Compact Full Preamble Structure */
     COMPACT_FULL(PREAMBLE_INTS_FULL, SERIAL_VERSION_EMPTY_FULL),
+    /** Updatable Preamble Structure */
     UPDATABLE(PREAMBLE_INTS_FULL, SERIAL_VERSION_UPDATABLE); //also used by the heap sketch.
 
     private int preInts;
@@ -522,10 +547,24 @@ private SketchStructure(final int preInts, final int serVer) {
       this.serVer = serVer;
     }
 
+    /**
+     * gets the Preamble Integers for this Structure.
+     * @return the Preamble Integers for this Structure
+     */
     public int getPreInts() { return preInts; }
 
+    /**
+     * gets the Serialization Version for this Structure.
+     * @return the Serialization Version for this Structure.
+     */
     public int getSerVer() { return serVer; }
 
+    /**
+     * gets the SketchStructure given preInts and serVer.
+     * @param preInts the given preamble size in integers
+     * @param serVer the given Serialization Version
+     * @return the SketchStructure given preInts and serVer.
+     */
     public static SketchStructure getSketchStructure(final int preInts, final int serVer) {
       final SketchStructure[] ssArr = SketchStructure.values();
       for (int i = 0; i < ssArr.length; i++) {

src/main/java/org/apache/datasketches/partitions/BoundsRule.java

@@ -19,6 +19,10 @@
 
 package org.apache.datasketches.partitions;
 
+/**
+ * This instructs the user about which of the upper and lower bounds of a partition definition row
+ * should be included with the returned data.
+ */
 public enum BoundsRule {
 
   /**
@@ -30,10 +34,12 @@ public enum BoundsRule {
    * Include only the upper bound but not the lower bound
    */
   INCLUDE_UPPER,
+
   /**
    * Include only the lower bound but not the upper bound
    */
   INCLUDE_LOWER,
+
   /**
    * Include none
    */

src/main/java/org/apache/datasketches/partitions/Partitioner.java

@@ -162,12 +162,22 @@ private void partitionSearch(final ArrayDeque<StackElement<T>> stack) {
 
   /**
    * Holds data for a Stack element
+   * @param <T> the item class type
    */
   public static class StackElement<T> {
+    /** A reference to the relevant GenericPartitionBoundaries class */
     public final GenericPartitionBoundaries<T> gpb;
+    /** The partition index */
     public int part;
+    /** A brief string description of the partition and its hierarchy */
     public String levelPartId;
 
+    /**
+     * Constructs this StackElement
+     * @param gpb the given GenericPartitionBoundarie reference
+     * @param part  The partition index
+     * @param levelPartId A brief string description of the partition and its hierarchy
+     */
     public StackElement(final GenericPartitionBoundaries<T> gpb, final int part, final String levelPartId) {
       this.gpb = gpb;
       this.part = part;
@@ -177,15 +187,26 @@ public StackElement(final GenericPartitionBoundaries<T> gpb, final int part, fin
 
   /**
    * Defines a row for List of PartitionBounds.
+   * @param <T> the item class type
    */
   public static class PartitionBoundsRow<T> {
+    /** The partition index */
     public int part;
+    /** A brief string description of the partition and its hierarchy */
     public String levelPartId;
+    /** The approximate number of items represented by this partition description row. */
     public long approxNumDeltaItems;
+    /** The BoundsRule for this partition description row. */
     public BoundsRule rule;
+    /** The lower bound value */
     public T lowerBound;
+    /** The upper bound value */
     public T upperBound;
 
+    /**
+     * The constructor for the StackElement class.
+     * @param se the given stack element.
+     */
     public PartitionBoundsRow(final StackElement<T> se) {
       final GenericPartitionBoundaries<T> gpb = se.gpb;
       final QuantileSearchCriteria searchCrit = gpb.getSearchCriteria();

src/main/java/org/apache/datasketches/partitions/SketchFillRequest.java

@@ -25,7 +25,8 @@
 /**
  * This is a callback request to the data source to fill a quantiles sketch,
  * which is returned to the caller.
- *
+ * @param <T> the item class type
+ * @param <S> the sketch type
  * @author Lee Rhodes
  */
 public interface SketchFillRequest<T, S extends QuantilesGenericAPI<T> & PartitioningFeature<T>> {

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

@@ -25,6 +25,12 @@
 public final class DoublesSortedViewIterator extends SortedViewIterator {
   private final double[] quantiles;
 
+  /**
+   * Constructor.
+   * @param quantiles the given array of quantiles, which must be ordered.
+   * @param cumWeights the given array of cumulative weights, which must be ordered, start with the value one, and
+   * the last value must be equal to N, the total number of items updated to the sketch.
+   */
   public DoublesSortedViewIterator(final double[] quantiles, final long[] cumWeights) {
     super(cumWeights);
     this.quantiles = quantiles; //SpotBugs EI_EXPOSE_REP2 suppressed by FindBugsExcludeFilter

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

@@ -25,6 +25,12 @@
 public final class FloatsSortedViewIterator extends SortedViewIterator {
   private final float[] quantiles;
 
+  /**
+   * Constructor.
+   * @param quantiles the given array of quantiles, which must be ordered.
+   * @param cumWeights the given array of cumulative weights, which must be ordered, start with the value one, and
+   * the last value must be equal to N, the total number of items updated to the sketch.
+   */
   public FloatsSortedViewIterator(final float[] quantiles, final long[] cumWeights) {
     super(cumWeights);
     this.quantiles = quantiles; //SpotBugs EI_EXPOSE_REP2 suppressed by FindBugsExcludeFilter

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

@@ -27,6 +27,7 @@
 /**
  * This defines the returned results of the getParitionBoundaries() function and
  * includes the basic methods needed to construct actual partitions.
+ * @param <T> the item class type
  */
 public final class GenericPartitionBoundaries<T> {
   private long totalN; //totalN of source sketch
@@ -40,6 +41,16 @@ public final class GenericPartitionBoundaries<T> {
   private long[] numDeltaItems; //num of items in each partition
   private int numPartitions;    //num of partitions
 
+  /**
+   * Constructor.
+   * @param totalN the total number of items input to the sketch.
+   * @param boundaries The quantile boundaries between partitions
+   * @param natRanks The array of natural Ranks corresponding to the array of boundaries.
+   * @param normRanks The normalized Ranks corresponding to the array of boundaries.
+   * @param maxItem the maximum item of the stream.
+   * @param minItem the minimum item of the stream.
+   * @param searchCrit the user defined search criteria
+   */
   public GenericPartitionBoundaries(
       final long totalN,
       final T[] boundaries,

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

@@ -23,11 +23,17 @@
 
 /**
  * Iterator over quantile sketches of generic type.
- * @param <T> The generic quantile type
+ * @param <T> The generic item class type
  */
 public class GenericSortedViewIterator<T> extends SortedViewIterator {
   private final T[] quantiles;
 
+  /**
+   * Constructor
+   * @param quantiles the given array of quantiles
+   * @param cumWeights the array of cumulative weights, corresponding to the array of quantiles,
+   * starting with the value one and the end value must equal N, the total number of items input to the sketch.
+   */
   public GenericSortedViewIterator(final T[] quantiles, final long[] cumWeights) {
     super(cumWeights);
     this.quantiles = quantiles; //SpotBugs EI_EXPOSE_REP2 suppressed by FindBugsExcludeFilter