Add support for the Querydsl IN operator in LdapSerializer.

src/main/java/org/springframework/data/ldap/repository/support/LdapSerializer.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.ldap.repository.support;
 
+import java.util.Collection;
+
 import org.springframework.ldap.filter.AndFilter;
 import org.springframework.ldap.filter.EqualsFilter;
 import org.springframework.ldap.filter.Filter;
@@ -33,6 +35,7 @@
  *
  * @author Mattias Hellborg Arthursson
  * @author Eddu Melendez
+ * @author Ashish Vaghela
  */
 class LdapSerializer implements Visitor<Object, Void> {
 
@@ -94,11 +97,35 @@ public Object visit(Operation<?> expr, Void context) {
 			return new GreaterThanOrEqualsFilter(attribute(expr), value(expr));
 		} else if (operator == Ops.LOE) {
 			return new LessThanOrEqualsFilter(attribute(expr), value(expr));
+		} else if (operator == Ops.IN) {
+			return inFilter(expr);
 		}
 
 		throw new UnsupportedOperationException("Unsupported operator " + operator.toString());
 	}
 
+	private Filter inFilter(Operation<?> expr) {
+
+		if (expr.getArg(1) instanceof Path) {
+			String attribute = odm.attributeFor(entityType, (String) expr.getArg(1).accept(this, null));
+			return new EqualsFilter(attribute, (String) expr.getArg(0).accept(this, null));
+		}
+
+		if (expr.getArg(1) instanceof Constant<?> constant && constant.getConstant() instanceof Collection<?> values) {
+
+			String attribute = attribute(expr);
+			OrFilter filter = new OrFilter();
+
+			for (Object value : values) {
+				filter.or(new EqualsFilter(attribute, value.toString()));
+			}
+
+			return filter;
+		}
+
+		throw new UnsupportedOperationException("Unsupported operand for IN operator: " + expr.getArg(1));
+	}
+
 	private String value(Operation<?> expr) {
 		return (String) expr.getArg(1).accept(this, null);
 	}

src/test/java/org/springframework/data/ldap/repository/support/QuerydslFilterGeneratorTests.java

@@ -27,6 +27,7 @@
 /**
  * @author Mattias Hellborg Arthursson
  * @author Eddu Melendez
+ * @author Ashish Vaghela
  */
 class QuerydslFilterGeneratorTests {
 
@@ -134,4 +135,31 @@ void testNull() {
 
 		assertThat(result).hasToString("(!(cn=*))");
 	}
+
+	@Test // GH-82
+	void testCollectionContains() {
+
+		Expression<?> expression = person.description.contains("test");
+		Filter result = tested.handle(expression);
+
+		assertThat(result).hasToString("(description=test)");
+	}
+
+	@Test // GH-82
+	void testIn() {
+
+		Expression<?> expression = person.fullName.in("John Doe", "Jane Doe");
+		Filter result = tested.handle(expression);
+
+		assertThat(result).hasToString("(|(cn=John Doe)(cn=Jane Doe))");
+	}
+
+	@Test // GH-82
+	void testInWithSingleValue() {
+
+		Expression<?> expression = person.fullName.in("John Doe");
+		Filter result = tested.handle(expression);
+
+		assertThat(result).hasToString("(cn=John Doe)");
+	}
 }