Drop "funny" functions building parsers (#50715) (#50814)

Replaces the "funny"
`Function<String, ConstructingObjectParser<T, Void>>` with a much
simpler `ConstructingObjectParser<T, String>`. This makes pretty much
all of our object parsers static.

client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/GetRollupCapsResponse.java

@@ -46,7 +46,7 @@ public static GetRollupCapsResponse fromXContent(final XContentParser parser) th
                 if (token.equals(XContentParser.Token.FIELD_NAME)) {
                     String pattern = parser.currentName();
 
-                    RollableIndexCaps cap = RollableIndexCaps.PARSER.apply(pattern).apply(parser, null);
+                    RollableIndexCaps cap = RollableIndexCaps.PARSER.parse(parser, pattern);
                     jobs.put(pattern, cap);
                 }
             }

client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/GetRollupIndexCapsResponse.java

@@ -46,7 +46,7 @@ public static GetRollupIndexCapsResponse fromXContent(final XContentParser parse
                 if (token.equals(XContentParser.Token.FIELD_NAME)) {
                     String pattern = parser.currentName();
 
-                    RollableIndexCaps cap = RollableIndexCaps.PARSER.apply(pattern).apply(parser, null);
+                    RollableIndexCaps cap = RollableIndexCaps.PARSER.apply(parser, pattern);
                     jobs.put(pattern, cap);
                 }
             }

client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollableIndexCaps.java

@@ -28,9 +28,10 @@
 import java.util.Comparator;
 import java.util.List;
 import java.util.Objects;
-import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
+
 /**
  * Represents the rollup capabilities of a non-rollup index.  E.g. what values/aggregations
  * were rolled up for this index, in what rollup jobs that data is stored and where those
@@ -41,16 +42,15 @@
 public class RollableIndexCaps implements ToXContentFragment {
     private static final ParseField ROLLUP_JOBS = new ParseField("rollup_jobs");
 
-    public static final Function<String, ConstructingObjectParser<RollableIndexCaps, Void>> PARSER = indexName -> {
-        @SuppressWarnings("unchecked")
-        ConstructingObjectParser<RollableIndexCaps, Void> p
-            = new ConstructingObjectParser<>(indexName, true,
-            a -> new RollableIndexCaps(indexName, (List<RollupJobCaps>) a[0]));
-
-        p.declareObjectArray(ConstructingObjectParser.constructorArg(), RollupJobCaps.PARSER::apply,
-            ROLLUP_JOBS);
-        return p;
-    };
+    public static final ConstructingObjectParser<RollableIndexCaps, String> PARSER = new ConstructingObjectParser<>(
+            ROLLUP_JOBS.getPreferredName(), true, (Object[] args, String indexName) -> {
+                @SuppressWarnings("unchecked")
+                List<RollupJobCaps> caps = (List<RollupJobCaps>) args[0];
+                return new RollableIndexCaps(indexName, caps);
+            });
+    static {
+        PARSER.declareObjectArray(constructorArg(), (p, name) -> RollupJobCaps.PARSER.parse(p, null), ROLLUP_JOBS);
+    }
 
     private final String indexName;
     private final List<RollupJobCaps> jobCaps;

server/src/main/java/org/elasticsearch/search/SearchModule.java

@@ -454,7 +454,7 @@ private void registerAggregations(List<SearchPlugin> plugins) {
         registerAggregation(new AggregationSpec(ScriptedMetricAggregationBuilder.NAME, ScriptedMetricAggregationBuilder::new,
                 ScriptedMetricAggregationBuilder::parse).addResultReader(InternalScriptedMetric::new));
         registerAggregation((new AggregationSpec(CompositeAggregationBuilder.NAME, CompositeAggregationBuilder::new,
-            CompositeAggregationBuilder::parse).addResultReader(InternalComposite::new)));
+                (name, p) -> CompositeAggregationBuilder.PARSER.parse(p, name)).addResultReader(InternalComposite::new)));
         registerFromPlugin(plugins, SearchPlugin::getAggregations, this::registerAggregation);
     }
 
@@ -540,7 +540,7 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
                 BucketScriptPipelineAggregationBuilder.NAME,
                 BucketScriptPipelineAggregationBuilder::new,
                 BucketScriptPipelineAggregator::new,
-                BucketScriptPipelineAggregationBuilder::parse));
+                (name, p) -> BucketScriptPipelineAggregationBuilder.PARSER.parse(p, name)));
         registerPipelineAggregation(new PipelineAggregationSpec(
                 BucketSelectorPipelineAggregationBuilder.NAME,
                 BucketSelectorPipelineAggregationBuilder::new,
@@ -557,10 +557,10 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
                 SerialDiffPipelineAggregator::new,
                 SerialDiffPipelineAggregationBuilder::parse));
         registerPipelineAggregation(new PipelineAggregationSpec(
-            MovFnPipelineAggregationBuilder.NAME,
-            MovFnPipelineAggregationBuilder::new,
-            MovFnPipelineAggregator::new,
-            MovFnPipelineAggregationBuilder::parse));
+                MovFnPipelineAggregationBuilder.NAME,
+                MovFnPipelineAggregationBuilder::new,
+                MovFnPipelineAggregator::new,
+                (name, p) -> MovFnPipelineAggregationBuilder.PARSER.parse(p, name)));
 
         registerFromPlugin(plugins, SearchPlugin::getPipelineAggregations, this::registerPipelineAggregation);
     }

server/src/main/java/org/elasticsearch/search/aggregations/bucket/composite/CompositeAggregationBuilder.java

@@ -24,7 +24,6 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.index.query.QueryShardContext;
 import org.elasticsearch.search.aggregations.AbstractAggregationBuilder;
 import org.elasticsearch.search.aggregations.AggregationBuilder;
@@ -39,7 +38,8 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
-import java.util.function.Function;
+
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
 
 public class CompositeAggregationBuilder extends AbstractAggregationBuilder<CompositeAggregationBuilder> {
     public static final String NAME = "composite";
@@ -48,27 +48,17 @@ public class CompositeAggregationBuilder extends AbstractAggregationBuilder<Comp
     public static final ParseField SIZE_FIELD_NAME = new ParseField("size");
     public static final ParseField SOURCES_FIELD_NAME = new ParseField("sources");
 
-    private static final Function<String, ConstructingObjectParser<CompositeAggregationBuilder, Void>> PARSER = name -> {
-        @SuppressWarnings("unchecked")
-        ConstructingObjectParser<CompositeAggregationBuilder, Void> parser = new ConstructingObjectParser<>(NAME, a -> {
-            CompositeAggregationBuilder builder = new CompositeAggregationBuilder(name, (List<CompositeValuesSourceBuilder<?>>)a[0]);
-            if (a[1] != null) {
-                builder.size((Integer)a[1]);
-            }
-            if (a[2] != null) {
-                builder.aggregateAfter((Map<String, Object>)a[2]);
-            }
-            return builder;
-        });
-        parser.declareObjectArray(ConstructingObjectParser.constructorArg(),
+    public static final ConstructingObjectParser<CompositeAggregationBuilder, String> PARSER = new ConstructingObjectParser<>(
+            NAME, false, (args, name) -> {
+                @SuppressWarnings("unchecked")
+                List<CompositeValuesSourceBuilder<?>> sources = (List<CompositeValuesSourceBuilder<?>>) args[0];
+                return new CompositeAggregationBuilder(name, sources);
+            });
+    static {
+        PARSER.declareObjectArray(constructorArg(),
             (p, c) -> CompositeValuesSourceParserHelper.fromXContent(p), SOURCES_FIELD_NAME);
-        parser.declareInt(ConstructingObjectParser.optionalConstructorArg(), SIZE_FIELD_NAME);
-        parser.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, context) -> p.map(), AFTER_FIELD_NAME);
-        return parser;
-    };
-
-    public static CompositeAggregationBuilder parse(String aggregationName, XContentParser parser) throws IOException {
-        return PARSER.apply(aggregationName).parse(parser, null);
+        PARSER.declareInt(CompositeAggregationBuilder::size, SIZE_FIELD_NAME);
+        PARSER.declareObject(CompositeAggregationBuilder::aggregateAfter, (p, context) -> p.map(), AFTER_FIELD_NAME);
     }
 
     private List<CompositeValuesSourceBuilder<?>> sources;

server/src/main/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptPipelineAggregationBuilder.java

@@ -37,8 +37,8 @@
 import java.util.Map.Entry;
 import java.util.Objects;
 import java.util.TreeMap;
-import java.util.function.Function;
 
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
 import static org.elasticsearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
 import static org.elasticsearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
 import static org.elasticsearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
@@ -51,31 +51,24 @@ public class BucketScriptPipelineAggregationBuilder extends AbstractPipelineAggr
     private String format = null;
     private GapPolicy gapPolicy = GapPolicy.SKIP;
 
-    private static final Function<String, ConstructingObjectParser<BucketScriptPipelineAggregationBuilder, Void>> PARSER
-        = name -> {
-
-        @SuppressWarnings("unchecked")
-        ConstructingObjectParser<BucketScriptPipelineAggregationBuilder, Void> parser = new ConstructingObjectParser<>(
-            BucketScriptPipelineAggregationBuilder.NAME,
-            false,
-            o -> new BucketScriptPipelineAggregationBuilder(name, (Map<String, String>) o[0], (Script) o[1]));
-
-        parser.declareField(ConstructingObjectParser.constructorArg()
-            , BucketScriptPipelineAggregationBuilder::extractBucketPath
-            , BUCKETS_PATH_FIELD
-            , ObjectParser.ValueType.OBJECT_ARRAY_OR_STRING);
-        parser.declareField(ConstructingObjectParser.constructorArg(),
-            (p, c) -> Script.parse(p), Script.SCRIPT_PARSE_FIELD, ObjectParser.ValueType.OBJECT_OR_STRING);
-
-        parser.declareString(BucketScriptPipelineAggregationBuilder::format, FORMAT);
-        parser.declareField(BucketScriptPipelineAggregationBuilder::gapPolicy, p -> {
+    public static final ConstructingObjectParser<BucketScriptPipelineAggregationBuilder, String> PARSER = new ConstructingObjectParser<>(
+            NAME, false, (args, name) -> {
+                @SuppressWarnings("unchecked")
+                Map<String, String> bucketsPathsMap = (Map<String, String>) args[0];
+                return new BucketScriptPipelineAggregationBuilder(name, bucketsPathsMap, (Script) args[1]);
+            });
+    static {
+        PARSER.declareField(constructorArg(), BucketScriptPipelineAggregationBuilder::extractBucketPath,
+                BUCKETS_PATH_FIELD, ObjectParser.ValueType.OBJECT_ARRAY_OR_STRING);
+        Script.declareScript(PARSER, constructorArg());
+
+        PARSER.declareString(BucketScriptPipelineAggregationBuilder::format, FORMAT);
+        PARSER.declareField(BucketScriptPipelineAggregationBuilder::gapPolicy, p -> {
             if (p.currentToken() == XContentParser.Token.VALUE_STRING) {
                 return GapPolicy.parse(p.text().toLowerCase(Locale.ROOT), p.getTokenLocation());
             }
             throw new IllegalArgumentException("Unsupported token [" + p.currentToken() + "]");
         }, GAP_POLICY, ObjectParser.ValueType.STRING);
-
-        return parser;
     };
 
 
@@ -205,10 +198,6 @@ protected XContentBuilder internalXContent(XContentBuilder builder, Params param
         return builder;
     }
 
-    public static BucketScriptPipelineAggregationBuilder parse(String aggName, XContentParser parser) {
-        return PARSER.apply(aggName).apply(parser, null);
-    }
-
     @Override
     protected boolean overrideBucketsPath() {
         return true;

server/src/main/java/org/elasticsearch/search/aggregations/pipeline/MovFnPipelineAggregationBuilder.java

@@ -40,8 +40,8 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
-import java.util.function.Function;
 
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
 import static org.elasticsearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
 import static org.elasticsearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
 import static org.elasticsearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
@@ -58,29 +58,23 @@ public class MovFnPipelineAggregationBuilder extends AbstractPipelineAggregation
     private int window;
     private int shift;
 
-    private static final Function<String, ConstructingObjectParser<MovFnPipelineAggregationBuilder, Void>> PARSER
-        = name -> {
-
-        ConstructingObjectParser<MovFnPipelineAggregationBuilder, Void> parser = new ConstructingObjectParser<>(
-            MovFnPipelineAggregationBuilder.NAME,
-            false,
-            o -> new MovFnPipelineAggregationBuilder(name, (String) o[0], (Script) o[1], (int)o[2]));
-
-        parser.declareString(ConstructingObjectParser.constructorArg(), BUCKETS_PATH_FIELD);
-        parser.declareField(ConstructingObjectParser.constructorArg(),
+    public static final ConstructingObjectParser<MovFnPipelineAggregationBuilder, String> PARSER = new ConstructingObjectParser<>(
+            NAME, false,
+            (args, name) -> new MovFnPipelineAggregationBuilder(name, (String) args[0], (Script) args[1], (int)args[2]));
+    static {
+        PARSER.declareString(constructorArg(), BUCKETS_PATH_FIELD);
+        PARSER.declareField(constructorArg(),
             (p, c) -> Script.parse(p), Script.SCRIPT_PARSE_FIELD, ObjectParser.ValueType.OBJECT_OR_STRING);
-        parser.declareInt(ConstructingObjectParser.constructorArg(), WINDOW);
+        PARSER.declareInt(constructorArg(), WINDOW);
 
-        parser.declareInt(MovFnPipelineAggregationBuilder::setShift, SHIFT);
-        parser.declareString(MovFnPipelineAggregationBuilder::format, FORMAT);
-        parser.declareField(MovFnPipelineAggregationBuilder::gapPolicy, p -> {
+        PARSER.declareInt(MovFnPipelineAggregationBuilder::setShift, SHIFT);
+        PARSER.declareString(MovFnPipelineAggregationBuilder::format, FORMAT);
+        PARSER.declareField(MovFnPipelineAggregationBuilder::gapPolicy, p -> {
             if (p.currentToken() == XContentParser.Token.VALUE_STRING) {
                 return GapPolicy.parse(p.text().toLowerCase(Locale.ROOT), p.getTokenLocation());
             }
             throw new IllegalArgumentException("Unsupported token [" + p.currentToken() + "]");
         }, GAP_POLICY, ObjectParser.ValueType.STRING);
-
-        return parser;
     };
 
 
@@ -212,10 +206,6 @@ protected XContentBuilder internalXContent(XContentBuilder builder, Params param
         return builder;
     }
 
-    public static MovFnPipelineAggregationBuilder parse(String aggName, XContentParser parser) {
-        return PARSER.apply(aggName).apply(parser, null);
-    }
-
     /**
      * Used for serialization testing, since pipeline aggs serialize themselves as a named object but are parsed
      * as a regular object with the name passed in.
@@ -228,7 +218,7 @@ static MovFnPipelineAggregationBuilder parse(XContentParser parser) throws IOExc
                 String aggName = parser.currentName();
                 parser.nextToken(); // "moving_fn"
                 parser.nextToken(); // start_object
-                return PARSER.apply(aggName).apply(parser, null);
+                return PARSER.apply(parser, aggName);
             }
         }
 

server/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptIT.java

@@ -645,7 +645,7 @@ public void testSingleBucketPathAgg() throws Exception {
             .endObject()
             .endObject();
         BucketScriptPipelineAggregationBuilder bucketScriptAgg =
-            BucketScriptPipelineAggregationBuilder.parse("seriesArithmetic", createParser(content));
+            BucketScriptPipelineAggregationBuilder.PARSER.parse(createParser(content), "seriesArithmetic");
 
         SearchResponse response = client()
             .prepareSearch("idx", "idx_unmapped")
@@ -690,7 +690,7 @@ public void testArrayBucketPathAgg() throws Exception {
             .endObject()
             .endObject();
         BucketScriptPipelineAggregationBuilder bucketScriptAgg =
-            BucketScriptPipelineAggregationBuilder.parse("seriesArithmetic", createParser(content));
+            BucketScriptPipelineAggregationBuilder.PARSER.parse(createParser(content), "seriesArithmetic");
 
         SearchResponse response = client()
             .prepareSearch("idx", "idx_unmapped")
@@ -747,7 +747,7 @@ public void testObjectBucketPathAgg() throws Exception {
             .endObject()
             .endObject();
         BucketScriptPipelineAggregationBuilder bucketScriptAgg =
-            BucketScriptPipelineAggregationBuilder.parse("seriesArithmetic", createParser(content));
+            BucketScriptPipelineAggregationBuilder.PARSER.parse(createParser(content), "seriesArithmetic");
 
         SearchResponse response = client()
             .prepareSearch("idx", "idx_unmapped")

server/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptTests.java

@@ -71,7 +71,8 @@ public void testParseBucketPath() throws IOException  {
                    .field("lang", "expression")
               .endObject()
             .endObject();
-        BucketScriptPipelineAggregationBuilder builder1 = BucketScriptPipelineAggregationBuilder.parse("count", createParser(content));
+        BucketScriptPipelineAggregationBuilder builder1 = BucketScriptPipelineAggregationBuilder.PARSER.parse(
+                createParser(content), "count");
         assertEquals(builder1.getBucketsPaths().length , 1);
         assertEquals(builder1.getBucketsPaths()[0], "_count");
 
@@ -86,7 +87,8 @@ public void testParseBucketPath() throws IOException  {
                 .field("lang", "expression")
               .endObject()
             .endObject();
-        BucketScriptPipelineAggregationBuilder builder2 = BucketScriptPipelineAggregationBuilder.parse("count", createParser(content));
+        BucketScriptPipelineAggregationBuilder builder2 = BucketScriptPipelineAggregationBuilder.PARSER.parse(
+                createParser(content), "count");
         assertEquals(builder2.getBucketsPaths().length , 2);
         assertEquals(builder2.getBucketsPaths()[0], "_count1");
         assertEquals(builder2.getBucketsPaths()[1], "_count2");
@@ -99,7 +101,8 @@ public void testParseBucketPath() throws IOException  {
                 .field("lang", "expression")
                .endObject()
             .endObject();
-        BucketScriptPipelineAggregationBuilder builder3 = BucketScriptPipelineAggregationBuilder.parse("count", createParser(content));
+        BucketScriptPipelineAggregationBuilder builder3 = BucketScriptPipelineAggregationBuilder.PARSER.parse(
+                createParser(content), "count");
         assertEquals(builder3.getBucketsPaths().length , 2);
         assertEquals(builder3.getBucketsPaths()[0], "_count1");
         assertEquals(builder3.getBucketsPaths()[1], "_count2");

x-pack/plugin/analytics/src/main/java/org/elasticsearch/xpack/analytics/AnalyticsPlugin.java

@@ -52,7 +52,7 @@ public List<PipelineAggregationSpec> getPipelineAggregations() {
                 CumulativeCardinalityPipelineAggregationBuilder.NAME,
                 CumulativeCardinalityPipelineAggregationBuilder::new,
                 CumulativeCardinalityPipelineAggregator::new,
-                CumulativeCardinalityPipelineAggregationBuilder::parse)
+                (name, p) -> CumulativeCardinalityPipelineAggregationBuilder.PARSER.parse(p, name))
         );
     }