1 files changed, 29 insertions, 7 deletions

diff --git a/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java b/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java
index ddd736e0d0..8e3c298270 100644
--- a/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java
+++ b/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java
@@ -29,6 +29,7 @@ import org.elasticsearch.common.xcontent.yaml.YamlXContent;
 
 import java.io.IOException;
 import java.util.Locale;
+import java.util.Objects;
 
 /**
  * The content type of {@link org.elasticsearch.common.xcontent.XContent}.
@@ -40,7 +41,7 @@ public enum XContentType implements Writeable {
      */
     JSON(0) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/json";
         }
 
@@ -64,7 +65,7 @@ public enum XContentType implements Writeable {
      */
     SMILE(1) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/smile";
         }
 
@@ -83,7 +84,7 @@ public enum XContentType implements Writeable {
      */
     YAML(2) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/yaml";
         }
 
@@ -102,7 +103,7 @@ public enum XContentType implements Writeable {
      */
     CBOR(3) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/cbor";
         }
 
@@ -117,12 +118,18 @@ public enum XContentType implements Writeable {
         }
     };
 
+    /**
+     * Accepts either a format string, which is equivalent to {@link XContentType#shortName()} or a media type that optionally has
+     * parameters and attempts to match the value to an {@link XContentType}. The comparisons are done in lower case format and this method
+     * also supports a wildcard accept for {@code application/*}. This method can be used to parse the {@code Accept} HTTP header or a
+     * format query string parameter. This method will return {@code null} if no match is found
+     */
     public static XContentType fromMediaTypeOrFormat(String mediaType) {
         if (mediaType == null) {
             return null;
         }
         for (XContentType type : values()) {
-            if (isSameMediaTypeAs(mediaType, type)) {
+            if (isSameMediaTypeOrFormatAs(mediaType, type)) {
                 return type;
             }
         }
@@ -133,7 +140,22 @@ public enum XContentType implements Writeable {
         return null;
     }
 
-    private static boolean isSameMediaTypeAs(String stringType, XContentType type) {
+    /**
+     * Attempts to match the given media type with the known {@link XContentType} values. This match is done in a case-insensitive manner.
+     * The provided media type should not include any parameters. This method is suitable for parsing part of the {@code Content-Type}
+     * HTTP header. This method will return {@code null} if no match is found
+     */
+    public static XContentType fromMediaType(String mediaType) {
+        final String lowercaseMediaType = Objects.requireNonNull(mediaType, "mediaType cannot be null").toLowerCase(Locale.ROOT);
+        for (XContentType type : values()) {
+            if (type.mediaTypeWithoutParameters().equals(lowercaseMediaType)) {
+                return type;
+            }
+        }
+        return null;
+    }
+
+    private static boolean isSameMediaTypeOrFormatAs(String stringType, XContentType type) {
         return type.mediaTypeWithoutParameters().equalsIgnoreCase(stringType) ||
                 stringType.toLowerCase(Locale.ROOT).startsWith(type.mediaTypeWithoutParameters().toLowerCase(Locale.ROOT) + ";") ||
                 type.shortName().equalsIgnoreCase(stringType);
@@ -157,7 +179,7 @@ public enum XContentType implements Writeable {
 
     public abstract XContent xContent();
 
-    protected abstract String mediaTypeWithoutParameters();
+    public abstract String mediaTypeWithoutParameters();
 
     public static XContentType readFrom(StreamInput in) throws IOException {
         int index = in.readVInt();