Parse EvluationMetrics as named Objects

modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/EvaluationMetric.java

@@ -19,16 +19,12 @@
 
 package org.elasticsearch.index.rankeval;
 
-import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.io.stream.NamedWriteable;
 import org.elasticsearch.common.xcontent.ToXContent;
-import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.common.xcontent.XContentParser.Token;
 import org.elasticsearch.index.rankeval.RatedDocument.DocumentKey;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.SearchHits;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -58,35 +54,6 @@ public interface EvaluationMetric extends ToXContent, NamedWriteable {
      */
     EvalQueryQuality evaluate(String taskId, SearchHit[] hits, List<RatedDocument> ratedDocs);
 
-    static EvaluationMetric fromXContent(XContentParser parser) throws IOException {
-        EvaluationMetric rc;
-        Token token = parser.nextToken();
-        if (token != XContentParser.Token.FIELD_NAME) {
-            throw new ParsingException(parser.getTokenLocation(), "[_na] missing required metric name");
-        }
-        String metricName = parser.currentName();
-
-        // TODO switch to using a plugable registry
-        switch (metricName) {
-        case PrecisionAtK.NAME:
-            rc = PrecisionAtK.fromXContent(parser);
-            break;
-        case MeanReciprocalRank.NAME:
-            rc = MeanReciprocalRank.fromXContent(parser);
-            break;
-        case DiscountedCumulativeGain.NAME:
-            rc = DiscountedCumulativeGain.fromXContent(parser);
-            break;
-        default:
-            throw new ParsingException(parser.getTokenLocation(), "[_na] unknown query metric name [{}]", metricName);
-        }
-        if (parser.currentToken() == XContentParser.Token.END_OBJECT) {
-            // if we are at END_OBJECT, move to the next one...
-            parser.nextToken();
-        }
-        return rc;
-    }
-
     /**
      * join hits with rated documents using the joint _index/_id document key
      */

modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalPlugin.java

@@ -23,11 +23,13 @@ import org.elasticsearch.action.ActionRequest;
 import org.elasticsearch.action.ActionResponse;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
+import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.settings.ClusterSettings;
 import org.elasticsearch.common.settings.IndexScopedSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsFilter;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.plugins.ActionPlugin;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.rest.RestController;
@@ -64,4 +66,16 @@ public class RankEvalPlugin extends Plugin implements ActionPlugin {
                 .add(new NamedWriteableRegistry.Entry(MetricDetails.class, MeanReciprocalRank.NAME, MeanReciprocalRank.Breakdown::new));
         return namedWriteables;
     }
+
+    @Override
+    public List<NamedXContentRegistry.Entry> getNamedXContent() {
+        List<NamedXContentRegistry.Entry> namedXContent = new ArrayList<>();
+        namedXContent.add(
+                new NamedXContentRegistry.Entry(EvaluationMetric.class, new ParseField(PrecisionAtK.NAME), PrecisionAtK::fromXContent));
+        namedXContent.add(new NamedXContentRegistry.Entry(EvaluationMetric.class, new ParseField(MeanReciprocalRank.NAME),
+                MeanReciprocalRank::fromXContent));
+        namedXContent.add(new NamedXContentRegistry.Entry(EvaluationMetric.class, new ParseField(DiscountedCumulativeGain.NAME),
+                DiscountedCumulativeGain::fromXContent));
+        return namedXContent;
+    }
 }

modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalSpec.java

@@ -29,6 +29,7 @@ import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentParserUtils;
 import org.elasticsearch.script.Script;
 
 import java.io.IOException;
@@ -169,22 +170,21 @@ public class RankEvalSpec implements Writeable, ToXContentObject {
             a -> new RankEvalSpec((List<RatedRequest>) a[0], (EvaluationMetric) a[1], (Collection<ScriptWithId>) a[2]));
 
     static {
-        PARSER.declareObjectArray(ConstructingObjectParser.constructorArg(), (p, c) -> {
+        PARSER.declareObjectArray(ConstructingObjectParser.constructorArg(), (p, c) -> RatedRequest.fromXContent(p), REQUESTS_FIELD);
-            return RatedRequest.fromXContent(p);
+        PARSER.declareObject(ConstructingObjectParser.constructorArg(), (p, c) -> parseMetric(p), METRIC_FIELD);
-        }, REQUESTS_FIELD);
+        PARSER.declareObjectArray(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> ScriptWithId.fromXContent(p),
-        PARSER.declareObject(ConstructingObjectParser.constructorArg(), (p, c) -> {
+                TEMPLATES_FIELD);
-            try {
-                return EvaluationMetric.fromXContent(p);
-            } catch (IOException ex) {
-                throw new ParsingException(p.getTokenLocation(), "error parsing rank request", ex);
-            }
-        }, METRIC_FIELD);
-        PARSER.declareObjectArray(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> {
-            return ScriptWithId.fromXContent(p);
-        }, TEMPLATES_FIELD);
         PARSER.declareInt(RankEvalSpec::setMaxConcurrentSearches, MAX_CONCURRENT_SEARCHES_FIELD);
     }
 
+    private static EvaluationMetric parseMetric(XContentParser parser) throws IOException {
+        XContentParserUtils.ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.currentToken(), parser::getTokenLocation);
+        XContentParserUtils.ensureExpectedToken(XContentParser.Token.FIELD_NAME, parser.nextToken(), parser::getTokenLocation);
+        EvaluationMetric metric = parser.namedObject(EvaluationMetric.class, parser.currentName(), null);
+        XContentParserUtils.ensureExpectedToken(XContentParser.Token.END_OBJECT, parser.nextToken(), parser::getTokenLocation);
+        return metric;
+    }
+
     public static RankEvalSpec parse(XContentParser parser) {
         return PARSER.apply(parser, null);
     }

modules/rank-eval/src/test/java/org/elasticsearch/index/rankeval/MeanReciprocalRankTests.java

@@ -166,7 +166,7 @@ public class MeanReciprocalRankTests extends ESTestCase {
         return hits;
     }
 
-    private static MeanReciprocalRank createTestItem() {
+    static MeanReciprocalRank createTestItem() {
         return new MeanReciprocalRank(randomIntBetween(0, 20));
     }
 

modules/rank-eval/src/test/java/org/elasticsearch/index/rankeval/RankEvalSpecTests.java

@@ -20,6 +20,7 @@
 package org.elasticsearch.index.rankeval;
 
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
@@ -49,6 +50,12 @@ import static org.elasticsearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashC
 
 public class RankEvalSpecTests extends ESTestCase {
 
+    @SuppressWarnings("resource")
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        return new NamedXContentRegistry(new RankEvalPlugin().getNamedXContent());
+    }
+
     private static <T> List<T> randomList(Supplier<T> randomSupplier) {
         List<T> result = new ArrayList<>();
         int size = randomIntBetween(1, 20);
@@ -59,12 +66,10 @@ public class RankEvalSpecTests extends ESTestCase {
     }
 
     private static RankEvalSpec createTestItem() throws IOException {
-        EvaluationMetric metric;
+        Supplier<EvaluationMetric> metric = randomFrom(Arrays.asList(
-        if (randomBoolean()) {
+                () -> PrecisionAtKTests.createTestItem(),
-            metric = PrecisionAtKTests.createTestItem();
+                () -> MeanReciprocalRankTests.createTestItem(),
-        } else {
+                () -> DiscountedCumulativeGainTests.createTestItem()));
-            metric = DiscountedCumulativeGainTests.createTestItem();
-        }
 
         List<RatedRequest> ratedRequests = null;
         Collection<ScriptWithId> templates = null;
@@ -92,7 +97,7 @@ public class RankEvalSpecTests extends ESTestCase {
                     new SearchSourceBuilder());
             ratedRequests = Arrays.asList(ratedRequest);
         }
-        RankEvalSpec spec = new RankEvalSpec(ratedRequests, metric, templates);
+        RankEvalSpec spec = new RankEvalSpec(ratedRequests, metric.get(), templates);
         maybeSet(spec::setMaxConcurrentSearches, randomInt(100));
         List<String> indices = new ArrayList<>();
         int size = randomIntBetween(0, 20);
@@ -105,7 +110,6 @@ public class RankEvalSpecTests extends ESTestCase {
 
     public void testXContentRoundtrip() throws IOException {
         RankEvalSpec testItem = createTestItem();
-
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS));
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, shuffled.bytes())) {
 

modules/rank-eval/src/test/java/org/elasticsearch/index/rankeval/RatedRequestsTests.java

@@ -53,9 +53,6 @@ public class RatedRequestsTests extends ESTestCase {
 
     private static NamedXContentRegistry xContentRegistry;
 
-    /**
-     * setup for the whole base test class
-     */
     @BeforeClass
     public static void init() {
         xContentRegistry = new NamedXContentRegistry(