[Javadocs] add to o.o.dfs,fetch,internal,lookup,profile, and query packages (#3261)

Adds class level javadocs to org.opensearch.dfs, fetch, internal, lookup,
profile, and query packages.

Signed-off-by: Nicholas Walter Knize <nknize@apache.org>

server/src/main/java/org/opensearch/search/dfs/AggregatedDfs.java

@@ -44,6 +44,11 @@ import org.opensearch.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Compute global distributed frequency across the index
+ *
+ * @opensearch.internal
+ */
 public class AggregatedDfs implements Writeable {
 
     private ObjectObjectHashMap<Term, TermStatistics> termStatistics;

server/src/main/java/org/opensearch/search/dfs/DfsPhase.java

@@ -51,6 +51,8 @@ import java.util.Map;
 /**
  * Dfs phase of a search request, used to make scoring 100% accurate by collecting additional info from each shard before the query phase.
  * The additional information is used to better compare the scores coming from all the shards, which depend on local factors (e.g. idf)
+ *
+ * @opensearch.internal
  */
 public class DfsPhase {
 

server/src/main/java/org/opensearch/search/dfs/DfsPhaseExecutionException.java

@@ -38,6 +38,11 @@ import org.opensearch.search.SearchShardTarget;
 
 import java.io.IOException;
 
+/**
+ * Thrown if there are any errors in the DFS phase
+ *
+ * @opensearch.internal
+ */
 public class DfsPhaseExecutionException extends SearchException {
 
     public DfsPhaseExecutionException(SearchShardTarget shardTarget, String msg, Throwable t) {

server/src/main/java/org/opensearch/search/dfs/DfsSearchResult.java

@@ -49,6 +49,11 @@ import org.opensearch.search.internal.ShardSearchRequest;
 
 import java.io.IOException;
 
+/**
+ * Result from a Distributed Frequency Search phase
+ *
+ * @opensearch.internal
+ */
 public class DfsSearchResult extends SearchPhaseResult {
 
     private static final Term[] EMPTY_TERMS = new Term[0];

server/src/main/java/org/opensearch/search/fetch/FetchContext.java

@@ -57,6 +57,8 @@ import java.util.List;
 
 /**
  * Encapsulates state required to execute fetch phases
+ *
+ * @opensearch.internal
  */
 public class FetchContext {
 

server/src/main/java/org/opensearch/search/fetch/FetchPhase.java

@@ -90,6 +90,8 @@ import static java.util.Collections.emptyMap;
 /**
  * Fetch phase of a search request, used to fetch the actual top matching documents to be returned to the client, identified
  * after reducing all of the matches returned by the query phase
+ *
+ * @opensearch.internal
  */
 public class FetchPhase {
     private static final Logger LOGGER = LogManager.getLogger(FetchPhase.class);

server/src/main/java/org/opensearch/search/fetch/FetchPhaseExecutionException.java

@@ -38,6 +38,11 @@ import org.opensearch.search.SearchShardTarget;
 
 import java.io.IOException;
 
+/**
+ * Thrown when there are errors during the fetch phase
+ *
+ * @opensearch.internal
+ */
 public class FetchPhaseExecutionException extends SearchException {
 
     public FetchPhaseExecutionException(SearchShardTarget shardTarget, String msg, Throwable t) {

server/src/main/java/org/opensearch/search/fetch/FetchSearchResult.java

@@ -43,6 +43,11 @@ import org.opensearch.search.query.QuerySearchResult;
 
 import java.io.IOException;
 
+/**
+ * Result from a fetch
+ *
+ * @opensearch.internal
+ */
 public final class FetchSearchResult extends SearchPhaseResult {
 
     private SearchHits hits;

server/src/main/java/org/opensearch/search/fetch/FetchSubPhase.java

@@ -42,6 +42,8 @@ import java.io.IOException;
 
 /**
  * Sub phase within the fetch phase used to fetch things *about* the documents like highlighting or matched queries.
+ *
+ * @opensearch.internal
  */
 public interface FetchSubPhase {
 

server/src/main/java/org/opensearch/search/fetch/FetchSubPhaseProcessor.java

@@ -39,6 +39,8 @@ import java.io.IOException;
 
 /**
  * Executes the logic for a {@link FetchSubPhase} against a particular leaf reader and hit
+ *
+ * @opensearch.internal
  */
 public interface FetchSubPhaseProcessor {
 

server/src/main/java/org/opensearch/search/fetch/QueryFetchSearchResult.java

@@ -41,6 +41,11 @@ import org.opensearch.search.query.QuerySearchResult;
 
 import java.io.IOException;
 
+/**
+ * Query fetch result
+ *
+ * @opensearch.internal
+ */
 public final class QueryFetchSearchResult extends SearchPhaseResult {
 
     private final QuerySearchResult queryResult;

server/src/main/java/org/opensearch/search/fetch/ScrollQueryFetchSearchResult.java

@@ -40,6 +40,11 @@ import org.opensearch.search.query.QuerySearchResult;
 
 import java.io.IOException;
 
+/**
+ * Scroll fetch result
+ *
+ * @opensearch.internal
+ */
 public final class ScrollQueryFetchSearchResult extends SearchPhaseResult {
 
     private final QueryFetchSearchResult result;

server/src/main/java/org/opensearch/search/fetch/ShardFetchRequest.java

@@ -54,6 +54,8 @@ import java.util.Map;
 /**
  * Shard level fetch base request. Holds all the info needed to execute a fetch.
  * Used with search scroll as the original request doesn't hold indices.
+ *
+ * @opensearch.internal
  */
 public class ShardFetchRequest extends TransportRequest {
 

server/src/main/java/org/opensearch/search/fetch/ShardFetchSearchRequest.java

@@ -50,6 +50,8 @@ import java.io.IOException;
 /**
  * Shard level fetch request used with search. Holds indices taken from the original search request
  * and implements {@link org.opensearch.action.IndicesRequest}.
+ *
+ * @opensearch.internal
  */
 public class ShardFetchSearchRequest extends ShardFetchRequest implements IndicesRequest {
 

server/src/main/java/org/opensearch/search/fetch/StoredFieldsContext.java

@@ -50,6 +50,8 @@ import java.util.Objects;
 
 /**
  * Context used to fetch the {@code stored_fields}.
+ *
+ * @opensearch.internal
  */
 public class StoredFieldsContext implements Writeable {
     public static final String _NONE_ = "_none_";

server/src/main/java/org/opensearch/search/fetch/subphase/ExplainPhase.java

@@ -42,6 +42,8 @@ import java.io.IOException;
 
 /**
  * Explains the scoring calculations for the top hits.
+ *
+ * @opensearch.internal
  */
 public final class ExplainPhase implements FetchSubPhase {
 

server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesContext.java

@@ -41,6 +41,8 @@ import java.util.function.Function;
 
 /**
  * All the required context to pull a field from the doc values.
+ *
+ * @opensearch.internal
  */
 public class FetchDocValuesContext {
     private final List<FieldAndFormat> fields;

server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesPhase.java

@@ -49,6 +49,8 @@ import java.util.List;
  * Fetch sub phase which pulls data from doc values.
  *
  * Specifying {@code "docvalue_fields": ["field1", "field2"]}
+ *
+ * @opensearch.internal
  */
 public final class FetchDocValuesPhase implements FetchSubPhase {
 

server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsContext.java

@@ -35,6 +35,8 @@ import java.util.List;
 
 /**
  * The context needed to retrieve fields.
+ *
+ * @opensearch.internal
  */
 public class FetchFieldsContext {
     private final List<FieldAndFormat> fields;

server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsPhase.java

@@ -50,6 +50,8 @@ import java.util.Set;
 /**
  * A fetch sub-phase for high-level field retrieval. Given a list of fields, it
  * retrieves the field values from _source and returns them as document fields.
+ *
+ * @opensearch.internal
  */
 public final class FetchFieldsPhase implements FetchSubPhase {
 

server/src/main/java/org/opensearch/search/fetch/subphase/FetchScorePhase.java

@@ -44,6 +44,11 @@ import org.opensearch.search.fetch.FetchSubPhaseProcessor;
 
 import java.io.IOException;
 
+/**
+ * Fetches the score of a query match during search phase
+ *
+ * @opensearch.internal
+ */
 public class FetchScorePhase implements FetchSubPhase {
 
     @Override

server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourceContext.java

@@ -54,6 +54,8 @@ import java.util.function.Function;
 
 /**
  * Context used to fetch the {@code _source}.
+ *
+ * @opensearch.internal
  */
 public class FetchSourceContext implements Writeable, ToXContentObject {
 

server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourcePhase.java

@@ -46,6 +46,11 @@ import org.opensearch.search.lookup.SourceLookup;
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Fetches the document source during search phase
+ *
+ * @opensearch.internal
+ */
 public final class FetchSourcePhase implements FetchSubPhase {
 
     @Override

server/src/main/java/org/opensearch/search/fetch/subphase/FetchVersionPhase.java

@@ -41,6 +41,11 @@ import org.opensearch.search.fetch.FetchSubPhaseProcessor;
 
 import java.io.IOException;
 
+/**
+ * Fetches the version of a term during search phase
+ *
+ * @opensearch.internal
+ */
 public final class FetchVersionPhase implements FetchSubPhase {
 
     @Override

server/src/main/java/org/opensearch/search/fetch/subphase/FieldAndFormat.java

@@ -49,6 +49,8 @@ import java.util.Objects;
 /**
  * Wrapper around a field name and the format that should be used to
  * display values of this field.
+ *
+ * @opensearch.internal
  */
 public final class FieldAndFormat implements Writeable, ToXContentObject {
     private static final ParseField FIELD_FIELD = new ParseField("field");

server/src/main/java/org/opensearch/search/fetch/subphase/FieldFetcher.java

@@ -51,6 +51,8 @@ import java.util.Set;
 /**
  * A helper class to {@link FetchFieldsPhase} that's initialized with a list of field patterns to fetch.
  * Then given a specific document, it can retrieve the corresponding fields from the document's source.
+ *
+ * @opensearch.internal
  */
 public class FieldFetcher {
     public static FieldFetcher create(QueryShardContext context, SearchLookup searchLookup, Collection<FieldAndFormat> fieldAndFormats) {

server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsContext.java

@@ -58,6 +58,8 @@ import java.util.Objects;
 
 /**
  * Context used for inner hits retrieval
+ *
+ * @opensearch.internal
  */
 public final class InnerHitsContext {
     private final Map<String, InnerHitSubContext> innerHits;

server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsPhase.java

@@ -49,6 +49,11 @@ import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Gets the inner hits of a document during search
+ *
+ * @opensearch.internal
+ */
 public final class InnerHitsPhase implements FetchSubPhase {
 
     private final FetchPhase fetchPhase;

server/src/main/java/org/opensearch/search/fetch/subphase/MatchedQueriesPhase.java

@@ -48,6 +48,11 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Fetches queries that match the document during search phase
+ *
+ * @opensearch.internal
+ */
 public final class MatchedQueriesPhase implements FetchSubPhase {
 
     @Override

server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsContext.java

@@ -37,6 +37,11 @@ import org.opensearch.script.FieldScript;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Context used for script fields
+ *
+ * @opensearch.internal
+ */
 public class ScriptFieldsContext {
 
     public static class ScriptField {

server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsPhase.java

@@ -45,6 +45,11 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Gets the scripted fields during search phase
+ *
+ * @opensearch.internal
+ */
 public final class ScriptFieldsPhase implements FetchSubPhase {
 
     @Override

server/src/main/java/org/opensearch/search/fetch/subphase/SeqNoPrimaryTermPhase.java

@@ -41,6 +41,11 @@ import org.opensearch.search.fetch.FetchSubPhaseProcessor;
 
 import java.io.IOException;
 
+/**
+ * Fetches the sequence number of the primary term during search phase
+ *
+ * @opensearch.internal
+ */
 public final class SeqNoPrimaryTermPhase implements FetchSubPhase {
 
     @Override

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/AbstractHighlighterBuilder.java

@@ -62,6 +62,8 @@ import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBui
 /**
  * This abstract class holds parameters shared by {@link HighlightBuilder} and {@link HighlightBuilder.Field}
  * and provides the common setters, equality, hashCode calculation and common serialization
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractHighlighterBuilder<HB extends AbstractHighlighterBuilder<?>>
     implements

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/CustomQueryScorer.java

@@ -43,6 +43,11 @@ import org.opensearch.index.search.OpenSearchToParentBlockJoinQuery;
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Internally used for custom scoring
+ *
+ * @opensearch.internal
+ */
 public final class CustomQueryScorer extends QueryScorer {
 
     public CustomQueryScorer(Query query, IndexReader reader, String field, String defaultField) {

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FastVectorHighlighter.java

@@ -64,6 +64,11 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Uses Lucene's Fast Vector Highlighting
+ *
+ * @opensearch.internal
+ */
 public class FastVectorHighlighter implements Highlighter {
     private static final BoundaryScanner DEFAULT_SIMPLE_BOUNDARY_SCANNER = new SimpleBoundaryScanner();
     private static final BoundaryScanner DEFAULT_SENTENCE_BOUNDARY_SCANNER = new BreakIteratorBoundaryScanner(

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FieldHighlightContext.java

@@ -38,6 +38,11 @@ import org.opensearch.search.fetch.FetchSubPhase;
 
 import java.util.Map;
 
+/**
+ * Context used during field level highlighting
+ *
+ * @opensearch.internal
+ */
 public class FieldHighlightContext {
 
     public final String fieldName;

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FragmentBuilderHelper.java

@@ -49,6 +49,8 @@ import java.util.List;
 
 /**
  * Simple helper class for {@link FastVectorHighlighter} {@link FragmentsBuilder} implementations.
+ *
+ * @opensearch.internal
  */
 public final class FragmentBuilderHelper {
 

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilder.java

@@ -67,6 +67,8 @@ import static org.opensearch.common.xcontent.ObjectParser.fromList;
  * are summarized to show only selected snippets ("fragments") containing search terms.
  *
  * @see org.opensearch.search.builder.SearchSourceBuilder#highlight()
+ *
+ * @opensearch.internal
  */
 public class HighlightBuilder extends AbstractHighlighterBuilder<HighlightBuilder> {
     /** default for whether to highlight fields based on the source even if stored separately */

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightField.java

@@ -51,6 +51,8 @@ import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedT
 
 /**
  * A field highlighted with its highlighted fragments.
+ *
+ * @opensearch.internal
  */
 public class HighlightField implements ToXContentFragment, Writeable {
 

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightPhase.java

@@ -51,6 +51,11 @@ import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Highlight Phase of the search request.
+ *
+ * @opensearch.internal
+ */
 public class HighlightPhase implements FetchSubPhase {
 
     private final Map<String, Highlighter> highlighters;

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightUtils.java

@@ -46,6 +46,11 @@ import java.util.List;
 
 import static java.util.Collections.singleton;
 
+/**
+ * Utility class used during the highlight phase of the search request.
+ *
+ * @opensearch.internal
+ */
 public final class HighlightUtils {
 
     // U+2029 PARAGRAPH SEPARATOR (PS): each value holds a discrete passage for highlighting (unified highlighter)

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/Highlighter.java

@@ -37,6 +37,8 @@ import java.io.IOException;
 
 /**
  * Highlights a search result.
+ *
+ * @opensearch.internal
  */
 public interface Highlighter {
 

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighter.java

@@ -61,6 +61,11 @@ import java.util.Map;
 
 import static org.opensearch.search.fetch.subphase.highlight.UnifiedHighlighter.convertFieldValue;
 
+/**
+ * Standard Lucene Highlighter implementation
+ *
+ * @opensearch.internal
+ */
 public class PlainHighlighter implements Highlighter {
     private static final String CACHE_KEY = "highlight-plain";
 

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SearchHighlightContext.java

@@ -43,6 +43,11 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Search context used during highlighting phase
+ *
+ * @opensearch.internal
+ */
 public class SearchHighlightContext {
 
     private final Map<String, Field> fields;

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SimpleFragmentsBuilder.java

@@ -40,6 +40,8 @@ import org.opensearch.index.mapper.MappedFieldType;
 /**
  * Direct Subclass of Lucene's org.apache.lucene.search.vectorhighlight.SimpleFragmentsBuilder
  * that corrects offsets for broken analysis chains.
+ *
+ * @opensearch.internal
  */
 public class SimpleFragmentsBuilder extends org.apache.lucene.search.vectorhighlight.SimpleFragmentsBuilder {
     protected final MappedFieldType fieldType;

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceScoreOrderFragmentsBuilder.java

@@ -44,6 +44,11 @@ import org.opensearch.search.lookup.SourceLookup;
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Internal builder used during source score lookup
+ *
+ * @opensearch.internal
+ */
 public class SourceScoreOrderFragmentsBuilder extends ScoreOrderFragmentsBuilder {
 
     private final MappedFieldType fieldType;

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceSimpleFragmentsBuilder.java

@@ -41,6 +41,11 @@ import org.opensearch.search.lookup.SourceLookup;
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Internal builder used during simple highlighting
+ *
+ * @opensearch.internal
+ */
 public class SourceSimpleFragmentsBuilder extends SimpleFragmentsBuilder {
 
     private final SourceLookup sourceLookup;

server/src/main/java/org/opensearch/search/fetch/subphase/highlight/UnifiedHighlighter.java

@@ -66,6 +66,11 @@ import java.util.stream.Collectors;
 
 import static org.apache.lucene.search.uhighlight.CustomUnifiedHighlighter.MULTIVAL_SEP_CHAR;
 
+/**
+ * Uses lucene's unified highlighter implementation
+ *
+ * @opensearch.internal
+ */
 public class UnifiedHighlighter implements Highlighter {
     @Override
     public boolean canHighlight(MappedFieldType fieldType) {

server/src/main/java/org/opensearch/search/internal/AliasFilter.java

@@ -46,6 +46,8 @@ import java.util.Objects;
 
 /**
  * Represents a {@link QueryBuilder} and a list of alias names that filters the builder is composed of.
+ *
+ * @opensearch.internal
  */
 public final class AliasFilter implements Writeable, Rewriteable<AliasFilter> {
 

server/src/main/java/org/opensearch/search/internal/CancellableBulkScorer.java

@@ -42,6 +42,8 @@ import java.util.Objects;
 /**
  * A {@link BulkScorer} wrapper that runs a {@link Runnable} on a regular basis
  * so that the query can be interrupted.
+ *
+ * @opensearch.internal
  */
 final class CancellableBulkScorer extends BulkScorer {
 

server/src/main/java/org/opensearch/search/internal/ContextIndexSearcher.java

@@ -84,6 +84,8 @@ import java.util.concurrent.Executor;
 
 /**
  * Context-aware extension of {@link IndexSearcher}.
+ *
+ * @opensearch.internal
  */
 public class ContextIndexSearcher extends IndexSearcher implements Releasable {
     /**

server/src/main/java/org/opensearch/search/internal/ExitableDirectoryReader.java

@@ -51,6 +51,8 @@ import java.io.IOException;
 /**
  * Wraps an {@link IndexReader} with a {@link QueryCancellation}
  * which checks for cancelled or timed-out query.
+ *
+ * @opensearch.internal
  */
 class ExitableDirectoryReader extends FilterDirectoryReader {
 

server/src/main/java/org/opensearch/search/internal/FilteredSearchContext.java

@@ -70,6 +70,11 @@ import org.opensearch.search.suggest.SuggestionSearchContext;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Context used during a filtered search
+ *
+ * @opensearch.internal
+ */
 public abstract class FilteredSearchContext extends SearchContext {
 
     private final SearchContext in;

server/src/main/java/org/opensearch/search/internal/InternalScrollSearchRequest.java

@@ -44,6 +44,11 @@ import org.opensearch.transport.TransportRequest;
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Internal request used during scroll search
+ *
+ * @opensearch.internal
+ */
 public class InternalScrollSearchRequest extends TransportRequest {
 
     private ShardSearchContextId contextId;

server/src/main/java/org/opensearch/search/internal/InternalSearchResponse.java

@@ -46,6 +46,8 @@ import java.io.IOException;
 
 /**
  * {@link SearchResponseSections} subclass that can be serialized over the wire.
+ *
+ * @opensearch.internal
  */
 public class InternalSearchResponse extends SearchResponseSections implements Writeable, ToXContentFragment {
     public static InternalSearchResponse empty() {

server/src/main/java/org/opensearch/search/internal/LegacyReaderContext.java

@@ -40,6 +40,11 @@ import org.opensearch.search.dfs.AggregatedDfs;
 
 import java.util.Objects;
 
+/**
+ * Reader context that does not hold a reference to a point in time Searcher
+ *
+ * @opensearch.internal
+ */
 public class LegacyReaderContext extends ReaderContext {
     private final ShardSearchRequest shardSearchRequest;
     private final ScrollContext scrollContext;

server/src/main/java/org/opensearch/search/internal/ReaderContext.java

@@ -56,6 +56,8 @@ import java.util.concurrent.atomic.AtomicLong;
  * in {@link org.opensearch.search.SearchService} a SearchContext can be closed concurrently due to independent events
  * ie. when an index gets removed. To prevent accessing closed IndexReader / IndexSearcher instances the SearchContext
  * can be guarded by a reference count and fail if it's been closed by an external event.
+ *
+ * @opensearch.internal
  */
 public class ReaderContext implements Releasable {
     private final ShardSearchContextId id;

server/src/main/java/org/opensearch/search/internal/ScrollContext.java

@@ -36,7 +36,11 @@ import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.search.Scroll;
 
-/** Wrapper around information that needs to stay around when scrolling. */
+/**
+ * Wrapper around information that needs to stay around when scrolling.
+ *
+ * @opensearch.internal
+ */
 public final class ScrollContext {
     public TotalHits totalHits = null;
     public float maxScore = Float.NaN;

server/src/main/java/org/opensearch/search/internal/SearchContext.java

@@ -83,6 +83,8 @@ import java.util.concurrent.atomic.AtomicBoolean;
  * This class encapsulates the state needed to execute a search. It holds a reference to the
  * shards point in time snapshot (IndexReader / ContextIndexSearcher) and allows passing on
  * state from one query / fetch phase to another.
+ *
+ * @opensearch.internal
  */
 public abstract class SearchContext implements Releasable {
 

server/src/main/java/org/opensearch/search/internal/ShardSearchContextId.java

@@ -40,6 +40,11 @@ import org.opensearch.common.io.stream.Writeable;
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Used to support Point in Time Searching
+ *
+ * @opensearch.internal
+ */
 public final class ShardSearchContextId implements Writeable {
     private final String sessionId;
     private final long id;

server/src/main/java/org/opensearch/search/internal/ShardSearchRequest.java

@@ -81,6 +81,8 @@ import static org.opensearch.search.internal.SearchContext.TRACK_TOTAL_HITS_DISA
  * Shard level request that represents a search.
  * It provides all the methods that the {@link SearchContext} needs.
  * Provides a cache key based on its content that can be used to cache shard level response.
+ *
+ * @opensearch.internal
  */
 public class ShardSearchRequest extends TransportRequest implements IndicesRequest {
     private final String clusterAlias;

server/src/main/java/org/opensearch/search/internal/SubSearchContext.java

@@ -49,6 +49,11 @@ import org.opensearch.search.suggest.SuggestionSearchContext;
 
 import java.util.List;
 
+/**
+ * Context for a sub search phase
+ *
+ * @opensearch.internal
+ */
 public class SubSearchContext extends FilteredSearchContext {
 
     // By default return 3 hits per bucket. A higher default would make the response really large by default, since

server/src/main/java/org/opensearch/search/lookup/DocLookup.java

@@ -38,6 +38,11 @@ import org.opensearch.index.mapper.MapperService;
 
 import java.util.function.Function;
 
+/**
+ * Looks up a document
+ *
+ * @opensearch.internal
+ */
 public class DocLookup {
 
     private final MapperService mapperService;

server/src/main/java/org/opensearch/search/lookup/FieldLookup.java

@@ -37,6 +37,11 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Look up a field
+ *
+ * @opensearch.internal
+ */
 public class FieldLookup {
 
     // we can cached fieldType completely per name, since its on an index/shard level (the lookup, and it does not change within the scope

server/src/main/java/org/opensearch/search/lookup/FieldsLookup.java

@@ -34,6 +34,11 @@ package org.opensearch.search.lookup;
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.index.mapper.MapperService;
 
+/**
+ * looks up multiple fields from a leaf reader
+ *
+ * @opensearch.internal
+ */
 public class FieldsLookup {
 
     private final MapperService mapperService;

server/src/main/java/org/opensearch/search/lookup/LeafDocLookup.java

@@ -47,6 +47,11 @@ import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
 
+/**
+ * Looks up a doc from a leaf reader
+ *
+ * @opensearch.internal
+ */
 public class LeafDocLookup implements Map<String, ScriptDocValues<?>> {
 
     private final Map<String, ScriptDocValues<?>> localCacheFieldData = new HashMap<>(4);

server/src/main/java/org/opensearch/search/lookup/LeafFieldsLookup.java

@@ -47,6 +47,11 @@ import java.util.Set;
 
 import static java.util.Collections.singletonMap;
 
+/**
+ * looks up multiple leaf fields
+ *
+ * @opensearch.internal
+ */
 public class LeafFieldsLookup implements Map {
 
     private final MapperService mapperService;

server/src/main/java/org/opensearch/search/lookup/LeafSearchLookup.java

@@ -41,6 +41,8 @@ import static java.util.Collections.unmodifiableMap;
 
 /**
  * Per-segment version of {@link SearchLookup}.
+ *
+ * @opensearch.internal
  */
 public class LeafSearchLookup {
 

server/src/main/java/org/opensearch/search/lookup/SearchLookup.java

@@ -44,6 +44,11 @@ import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.function.Supplier;
 
+/**
+ * Orchestrator class for search phase lookups
+ *
+ * @opensearch.internal
+ */
 public class SearchLookup {
     /**
      * The maximum depth of field dependencies.

server/src/main/java/org/opensearch/search/lookup/SourceLookup.java

@@ -54,6 +54,11 @@ import java.util.Set;
 
 import static java.util.Collections.emptyMap;
 
+/**
+ * Orchestrator class for source lookups
+ *
+ * @opensearch.internal
+ */
 public class SourceLookup implements Map {
 
     private LeafReader reader;

server/src/main/java/org/opensearch/search/profile/AbstractInternalProfileTree.java

@@ -40,6 +40,11 @@ import java.util.Collections;
 import java.util.Deque;
 import java.util.List;
 
+/**
+ * Base class for a profiling tree.
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractInternalProfileTree<PB extends AbstractProfileBreakdown<?>, E> {
 
     protected ArrayList<PB> breakdowns;

server/src/main/java/org/opensearch/search/profile/AbstractProfileBreakdown.java

@@ -42,6 +42,8 @@ import static java.util.Collections.emptyMap;
  * A record of timings for the various operations that may happen during query execution.
  * A node's time may be composed of several internal attributes (rewriting, weighting,
  * scoring, etc).
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractProfileBreakdown<T extends Enum<T>> {
 

server/src/main/java/org/opensearch/search/profile/AbstractProfiler.java

@@ -34,6 +34,11 @@ package org.opensearch.search.profile;
 
 import java.util.List;
 
+/**
+ * Base class for a profiler
+ *
+ * @opensearch.internal
+ */
 public class AbstractProfiler<PB extends AbstractProfileBreakdown<?>, E> {
 
     protected final AbstractInternalProfileTree<PB, E> profileTree;

server/src/main/java/org/opensearch/search/profile/ContextualProfileBreakdown.java

@@ -11,6 +11,8 @@ package org.opensearch.search.profile;
 /**
  * Provide contextual profile breakdowns which are associated with freestyle context. Used when concurrent
  * search over segments is activated and each collector needs own non-shareable profile breakdown instance.
+ *
+ * @opensearch.internal
  */
 public abstract class ContextualProfileBreakdown<T extends Enum<T>> extends AbstractProfileBreakdown<T> {
     public ContextualProfileBreakdown(Class<T> clazz) {

server/src/main/java/org/opensearch/search/profile/NetworkTime.java

@@ -15,6 +15,11 @@ import org.opensearch.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Utility class to track time of network operations
+ *
+ * @opensearch.internal
+ */
 public class NetworkTime implements Writeable {
     private long inboundNetworkTime;
     private long outboundNetworkTime;

server/src/main/java/org/opensearch/search/profile/ProfileResult.java

@@ -61,6 +61,8 @@ import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalCo
  * <p>
  * Each InternalProfileResult has a List of InternalProfileResults, which will contain
  * "children" queries if applicable
+ *
+ * @opensearch.internal
  */
 public final class ProfileResult implements Writeable, ToXContentObject {
     static final ParseField TYPE = new ParseField("type");

server/src/main/java/org/opensearch/search/profile/ProfileShardResult.java

@@ -43,6 +43,11 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Shard level profile results
+ *
+ * @opensearch.internal
+ */
 public class ProfileShardResult implements Writeable {
 
     private final List<QueryProfileShardResult> queryProfileResults;

server/src/main/java/org/opensearch/search/profile/Profilers.java

@@ -40,7 +40,11 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-/** Wrapper around all the profilers that makes management easier. */
+/**
+ * Wrapper around all the profilers that makes management easier.
+ *
+ * @opensearch.internal
+ */
 public final class Profilers {
 
     private final ContextIndexSearcher searcher;

server/src/main/java/org/opensearch/search/profile/SearchProfileShardResults.java

@@ -57,6 +57,8 @@ import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedT
 /**
  * A container class to hold all the profile results across all shards.  Internally
  * holds a map of shard ID -> Profiled results
+ *
+ * @opensearch.internal
  */
 public final class SearchProfileShardResults implements Writeable, ToXContentFragment {
     private static final String SEARCHES_FIELD = "searches";

server/src/main/java/org/opensearch/search/profile/Timer.java

@@ -45,6 +45,8 @@ package org.opensearch.search.profile;
  *    timer.stop();
  *  }
  *  </pre>
+ *
+ *  @opensearch.internal
  */
 public class Timer {
 

server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileBreakdown.java

@@ -41,6 +41,8 @@ import static java.util.Collections.unmodifiableMap;
 
 /**
  * {@linkplain AbstractProfileBreakdown} customized to work with aggregations.
+ *
+ * @opensearch.internal
  */
 public class AggregationProfileBreakdown extends AbstractProfileBreakdown<AggregationTimingType> {
     private final Map<String, Object> extra = new HashMap<>();

server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResult.java

@@ -50,6 +50,8 @@ import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedT
 /**
  * A container class to hold the profile results for a single shard in the request.
  * Contains a list of query profiles, a collector tree and a total rewrite tree.
+ *
+ * @opensearch.internal
  */
 public final class AggregationProfileShardResult implements Writeable, ToXContentFragment {
 

server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfiler.java

@@ -40,6 +40,11 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Main class to profile aggregations
+ *
+ * @opensearch.internal
+ */
 public class AggregationProfiler extends AbstractProfiler<AggregationProfileBreakdown, Aggregator> {
 
     private final Map<List<String>, AggregationProfileBreakdown> profileBreakdownLookup = new HashMap<>();

server/src/main/java/org/opensearch/search/profile/aggregation/AggregationTimingType.java

@@ -34,6 +34,11 @@ package org.opensearch.search.profile.aggregation;
 
 import java.util.Locale;
 
+/**
+ * Timing levels for aggregations
+ *
+ * @opensearch.internal
+ */
 public enum AggregationTimingType {
     INITIALIZE,
     BUILD_LEAF_COLLECTOR,

server/src/main/java/org/opensearch/search/profile/aggregation/InternalAggregationProfileTree.java

@@ -35,6 +35,11 @@ package org.opensearch.search.profile.aggregation;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.profile.AbstractInternalProfileTree;
 
+/**
+ * The profiling tree for different levels of agg profiling
+ *
+ * @opensearch.internal
+ */
 public class InternalAggregationProfileTree extends AbstractInternalProfileTree<AggregationProfileBreakdown, Aggregator> {
 
     @Override

server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingAggregator.java

@@ -45,6 +45,9 @@ import org.opensearch.search.sort.SortOrder;
 import java.io.IOException;
 import java.util.Iterator;
 
+/**
+ * An aggregator that aggregates the performance profiling of other aggregations
+ */
 public class ProfilingAggregator extends Aggregator {
 
     private final Aggregator delegate;

server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingLeafBucketCollector.java

@@ -38,6 +38,11 @@ import org.opensearch.search.profile.Timer;
 
 import java.io.IOException;
 
+/**
+ * The collector for the agg profiles
+ *
+ * @opensearch.internal
+ */
 public class ProfilingLeafBucketCollector extends LeafBucketCollector {
 
     private LeafBucketCollector delegate;

server/src/main/java/org/opensearch/search/profile/query/CollectorResult.java

@@ -53,6 +53,8 @@ import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedT
  * Public interface and serialization container for profiled timings of the
  * Collectors used in the search.  Children CollectorResult's may be
  * embedded inside of a parent CollectorResult
+ *
+ * @opensearch.internal
  */
 public class CollectorResult implements ToXContentObject, Writeable {
 

server/src/main/java/org/opensearch/search/profile/query/ConcurrentQueryProfileBreakdown.java

@@ -19,6 +19,8 @@ import java.util.concurrent.ConcurrentHashMap;
  * A record of timings for the various operations that may happen during query execution.
  * A node's time may be composed of several internal attributes (rewriting, weighting,
  * scoring, etc). The class supports profiling the concurrent search over segments.
+ *
+ * @opensearch.internal
  */
 public final class ConcurrentQueryProfileBreakdown extends ContextualProfileBreakdown<QueryTimingType> {
     private final Map<Object, AbstractProfileBreakdown<QueryTimingType>> contexts = new ConcurrentHashMap<>();

server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollector.java

@@ -50,6 +50,8 @@ import java.util.List;
  * - needsScores()
  *
  * InternalProfiler facilitates the linking of the Collector graph
+ *
+ * @opensearch.internal
  */
 public class InternalProfileCollector implements Collector, InternalProfileComponent {
 

server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollectorManager.java

@@ -18,6 +18,11 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 
+/**
+ * Collector Manager for internal agg profiling
+ *
+ * @opensearch.internal
+ */
 public class InternalProfileCollectorManager
     implements
         ProfileCollectorManager<InternalProfileCollector, ReduceableSearchResult>,

server/src/main/java/org/opensearch/search/profile/query/InternalProfileComponent.java

@@ -10,6 +10,11 @@ package org.opensearch.search.profile.query;
 
 import java.util.Collection;
 
+/**
+ * Container for an agg profiling component
+ *
+ * @opensearch.internal
+ */
 public interface InternalProfileComponent {
     /**
      * @return profile component name

server/src/main/java/org/opensearch/search/profile/query/InternalQueryProfileTree.java

@@ -41,6 +41,8 @@ import org.opensearch.search.profile.ProfileResult;
  * This class tracks the dependency tree for queries (scoring and rewriting) and
  * generates {@link QueryProfileBreakdown} for each node in the tree.  It also finalizes the tree
  * and returns a list of {@link ProfileResult} that can be serialized back to the client
+ *
+ * @opensearch.internal
  */
 final class InternalQueryProfileTree extends AbstractInternalProfileTree<ContextualProfileBreakdown<QueryTimingType>, Query> {
 

server/src/main/java/org/opensearch/search/profile/query/ProfileCollector.java

@@ -42,7 +42,11 @@ import org.apache.lucene.search.ScoreMode;
 
 import java.io.IOException;
 
-/** A collector that profiles how much time is spent calling it. */
+/**
+ * A collector that profiles how much time is spent calling it.
+ *
+ * @opensearch.internal
+ */
 final class ProfileCollector extends FilterCollector {
 
     private long time;

server/src/main/java/org/opensearch/search/profile/query/ProfileCollectorManager.java

@@ -13,5 +13,7 @@ import org.apache.lucene.search.CollectorManager;
 
 /**
  * Collector manager which supports profiling
+ *
+ * @opensearch.internal
  */
 public interface ProfileCollectorManager<C extends Collector, T> extends CollectorManager<C, T>, InternalProfileComponent {}

server/src/main/java/org/opensearch/search/profile/query/ProfileScorer.java

@@ -45,6 +45,8 @@ import java.util.Collection;
 /**
  * {@link Scorer} wrapper that will compute how much time is spent on moving
  * the iterator, confirming matches and computing scores.
+ *
+ * @opensearch.internal
  */
 final class ProfileScorer extends Scorer {
 

server/src/main/java/org/opensearch/search/profile/query/ProfileWeight.java

@@ -48,6 +48,8 @@ import java.io.IOException;
  * Weight wrapper that will compute how much time it takes to build the
  * {@link Scorer} and then return a {@link Scorer} that is wrapped in
  * order to compute timings as well.
+ *
+ * @opensearch.internal
  */
 public final class ProfileWeight extends Weight {
 

server/src/main/java/org/opensearch/search/profile/query/QueryProfileBreakdown.java

@@ -39,6 +39,8 @@ import org.opensearch.search.profile.ContextualProfileBreakdown;
  * A record of timings for the various operations that may happen during query execution.
  * A node's time may be composed of several internal attributes (rewriting, weighting,
  * scoring, etc).
+ *
+ * @opensearch.internal
  */
 public final class QueryProfileBreakdown extends ContextualProfileBreakdown<QueryTimingType> {
 

server/src/main/java/org/opensearch/search/profile/query/QueryProfileShardResult.java

@@ -50,6 +50,8 @@ import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedT
 /**
  * A container class to hold the profile results for a single shard in the request.
  * Contains a list of query profiles, a collector tree and a total rewrite tree.
+ *
+ * @opensearch.internal
  */
 public final class QueryProfileShardResult implements Writeable, ToXContentObject {
 

server/src/main/java/org/opensearch/search/profile/query/QueryProfiler.java

@@ -48,6 +48,8 @@ import java.util.Objects;
  * A Profiler is associated with every Search, not per Search-Request. E.g. a
  * request may execute two searches (query + global agg).  A Profiler just
  * represents one of those
+ *
+ * @opensearch.internal
  */
 public final class QueryProfiler extends AbstractProfiler<ContextualProfileBreakdown<QueryTimingType>, Query> {