Wrap up building parametrized TypeParsers (#59977)

The TypeParser implementations of all ParametrizedFieldMapper descendant classes are
essentially the same - stateless, requiring the construction of a Builder object, and calling
parse on it before returning it. We can make this easier (and less error-prone) to
implement by wrapping the logic up into a final class, which takes a function to produce
the Builder from a name and parser context.

server/src/main/java/org/elasticsearch/index/mapper/BinaryFieldMapper.java

@@ -82,15 +82,7 @@ public class BinaryFieldMapper extends ParametrizedFieldMapper {
         }
     }
 
-    public static class TypeParser implements Mapper.TypeParser {
+    public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n));
-        @Override
-        public BinaryFieldMapper.Builder parse(String name, Map<String, Object> node, ParserContext parserContext)
-                throws MapperParsingException {
-            BinaryFieldMapper.Builder builder = new BinaryFieldMapper.Builder(name);
-            builder.parse(name, parserContext, node);
-            return builder;
-        }
-    }
 
     public static final class BinaryFieldType extends MappedFieldType {
 

server/src/main/java/org/elasticsearch/index/mapper/BooleanFieldMapper.java

@@ -102,15 +102,7 @@ public class BooleanFieldMapper extends ParametrizedFieldMapper {
         }
     }
 
-    public static class TypeParser implements Mapper.TypeParser {
+    public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n));
-        @Override
-        public BooleanFieldMapper.Builder parse(String name, Map<String, Object> node, ParserContext parserContext)
-                throws MapperParsingException {
-            BooleanFieldMapper.Builder builder = new BooleanFieldMapper.Builder(name);
-            builder.parse(name, parserContext, node);
-            return builder;
-        }
-    }
 
     public static final class BooleanFieldType extends TermBasedFieldType {
 

server/src/main/java/org/elasticsearch/index/mapper/CompletionFieldMapper.java

@@ -220,17 +220,7 @@ public class CompletionFieldMapper extends ParametrizedFieldMapper {
     public static final Set<String> ALLOWED_CONTENT_FIELD_NAMES = Sets.newHashSet(Fields.CONTENT_FIELD_NAME_INPUT,
             Fields.CONTENT_FIELD_NAME_WEIGHT, Fields.CONTENT_FIELD_NAME_CONTEXTS);
 
-    public static class TypeParser implements Mapper.TypeParser {
+    public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n, c.getIndexAnalyzers().get("simple")));
-
-        @Override
-        public Mapper.Builder<?> parse(String name, Map<String, Object> node, ParserContext parserContext)
-                throws MapperParsingException {
-            CompletionFieldMapper.Builder builder
-                = new CompletionFieldMapper.Builder(name, parserContext.getIndexAnalyzers().get("simple"));
-            builder.parse(name, parserContext, node);
-            return builder;
-        }
-    }
 
     public static final class CompletionFieldType extends TermBasedFieldType {
 

server/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java

@@ -227,23 +227,15 @@ public final class DateFieldMapper extends ParametrizedFieldMapper {
         }
     }
 
-    public static class TypeParser implements Mapper.TypeParser {
+    public static final TypeParser MILLIS_PARSER = new TypeParser((n, c) -> {
+        boolean ignoreMalformedByDefault = IGNORE_MALFORMED_SETTING.get(c.getSettings());
+        return new Builder(n, c.indexVersionCreated(), Resolution.MILLISECONDS, c.getDateFormatter(), ignoreMalformedByDefault);
+    });
 
-        private final Resolution resolution;
+    public static final TypeParser NANOS_PARSER = new TypeParser((n, c) -> {
-
+        boolean ignoreMalformedByDefault = IGNORE_MALFORMED_SETTING.get(c.getSettings());
-        public TypeParser(Resolution resolution) {
+        return new Builder(n, c.indexVersionCreated(), Resolution.NANOSECONDS, c.getDateFormatter(), ignoreMalformedByDefault);
-            this.resolution = resolution;
+    });
-        }
-
-        @Override
-        public Mapper.Builder<?> parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
-            boolean ignoreMalformedByDefault = IGNORE_MALFORMED_SETTING.get(parserContext.getSettings());
-            Builder builder = new Builder(name, parserContext.indexVersionCreated(), resolution,
-                parserContext.getDateFormatter(), ignoreMalformedByDefault);
-            builder.parse(name, parserContext, node);
-            return builder;
-        }
-    }
 
     public static final class DateFieldType extends MappedFieldType {
         protected final DateFormatter dateTimeFormatter;

server/src/main/java/org/elasticsearch/index/mapper/ParametrizedFieldMapper.java

@@ -41,6 +41,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -504,4 +505,27 @@ public abstract class ParametrizedFieldMapper extends FieldMapper {
             return DEPRECATED_PARAMS.contains(propName);
         }
     }
+
+    /**
+     * TypeParser implementation that automatically handles parsing
+     */
+    public static final class TypeParser implements Mapper.TypeParser {
+
+        private final BiFunction<String, ParserContext, Builder> builderFunction;
+
+        /**
+         * Creates a new TypeParser
+         * @param builderFunction a function that produces a Builder from a name and parsercontext
+         */
+        public TypeParser(BiFunction<String, ParserContext, Builder> builderFunction) {
+            this.builderFunction = builderFunction;
+        }
+
+        @Override
+        public Builder parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
+            Builder builder = builderFunction.apply(name, parserContext);
+            builder.parse(name, parserContext, node);
+            return builder;
+        }
+    }
 }

server/src/main/java/org/elasticsearch/indices/IndicesModule.java

@@ -119,18 +119,18 @@ public class IndicesModule extends AbstractModule {
         for (RangeType type : RangeType.values()) {
             mappers.put(type.typeName(), new RangeFieldMapper.TypeParser(type));
         }
-        mappers.put(BooleanFieldMapper.CONTENT_TYPE, new BooleanFieldMapper.TypeParser());
+        mappers.put(BooleanFieldMapper.CONTENT_TYPE, BooleanFieldMapper.PARSER);
-        mappers.put(BinaryFieldMapper.CONTENT_TYPE, new BinaryFieldMapper.TypeParser());
+        mappers.put(BinaryFieldMapper.CONTENT_TYPE, BinaryFieldMapper.PARSER);
         DateFieldMapper.Resolution milliseconds = DateFieldMapper.Resolution.MILLISECONDS;
-        mappers.put(milliseconds.type(), new DateFieldMapper.TypeParser(milliseconds));
+        mappers.put(milliseconds.type(), DateFieldMapper.MILLIS_PARSER);
         DateFieldMapper.Resolution nanoseconds = DateFieldMapper.Resolution.NANOSECONDS;
-        mappers.put(nanoseconds.type(), new DateFieldMapper.TypeParser(nanoseconds));
+        mappers.put(nanoseconds.type(), DateFieldMapper.NANOS_PARSER);
         mappers.put(IpFieldMapper.CONTENT_TYPE, new IpFieldMapper.TypeParser());
         mappers.put(TextFieldMapper.CONTENT_TYPE, new TextFieldMapper.TypeParser());
         mappers.put(KeywordFieldMapper.CONTENT_TYPE, new KeywordFieldMapper.TypeParser());
         mappers.put(ObjectMapper.CONTENT_TYPE, new ObjectMapper.TypeParser());
         mappers.put(ObjectMapper.NESTED_CONTENT_TYPE, new ObjectMapper.TypeParser());
-        mappers.put(CompletionFieldMapper.CONTENT_TYPE, new CompletionFieldMapper.TypeParser());
+        mappers.put(CompletionFieldMapper.CONTENT_TYPE, CompletionFieldMapper.PARSER);
         mappers.put(FieldAliasMapper.CONTENT_TYPE, new FieldAliasMapper.TypeParser());
         mappers.put(GeoPointFieldMapper.CONTENT_TYPE, new GeoPointFieldMapper.TypeParser());
 

server/src/test/java/org/elasticsearch/index/mapper/ParametrizedMapperTests.java

@@ -198,7 +198,7 @@ public class ParametrizedMapperTests extends ESSingleNodeTestCase {
                 return new KeywordFieldMapper.TypeParser();
             }
             if (Objects.equals("binary", s)) {
-                return new BinaryFieldMapper.TypeParser();
+                return BinaryFieldMapper.PARSER;
             }
             return null;
         }, version, () -> null, null);