JAVA-2093: Add overloaded eq method to Filters to filter by the value of the _id field

Author: jyemin

driver-core/src/main/com/mongodb/client/model/Filters.java

@@ -53,6 +53,21 @@ public final class Filters {
     private Filters() {
     }
 
+    /**
+     * Creates a filter that matches all documents where the value of _id field equalss the specified value. Note that this does
+     * actually generate a $eq operator, as the query language doesn't require it.
+     *
+     * @param value     the value
+     * @param <TItem>   the value type
+     * @return the filter
+     * @mongodb.driver.manual reference/operator/query/eq $eq
+     *
+     * @since 3.4
+     */
+    public static <TItem> Bson eq(final TItem value) {
+        return eq("_id", value);
+    }
+
     /**
      * Creates a filter that matches all documents where the value of the field name equals the specified value. Note that this does
      * actually generate a $eq operator, as the query language doesn't require it.

driver-core/src/test/functional/com/mongodb/client/model/FiltersFunctionalSpecification.groovy

@@ -78,6 +78,7 @@ class FiltersFunctionalSpecification extends OperationFunctionalSpecification {
     def 'eq'() {
         expect:
         find(eq('x', 1)) == [a]
+        find(eq(2)) == [b]
     }
 
     def '$ne'() {

driver-core/src/test/unit/com/mongodb/client/model/FiltersSpecification.groovy

@@ -80,6 +80,7 @@ class FiltersSpecification extends Specification {
         expect:
         toBson(eq('x', 1)) == parse('{x : 1}')
         toBson(eq('x', null)) == parse('{x : null}')
+        toBson(eq(1)) == parse('{_id : 1}')
     }
 
     def 'should render $ne'() {