DATALDAP-65 - Fix query execution without predicates using Querydsl.

Query execution without a predicate now no longer fails but falls back to LdapOperations.findAll(…). Previously, we did not initialize the filter of LdapQuery which caused an IllegalStateException in LdapOperations.find(…).

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

@@ -20,6 +20,7 @@ import static org.springframework.ldap.query.LdapQueryBuilder.*;
 import java.util.List;
 
 import org.springframework.ldap.core.LdapOperations;
+import org.springframework.ldap.filter.AbsoluteTrueFilter;
 import org.springframework.ldap.query.LdapQuery;
 import org.springframework.util.Assert;
 
@@ -75,25 +76,32 @@ public class QuerydslLdapQuery<K> implements FilteredClause<QuerydslLdapQuery<K>
 	 */
 	@Override
 	public QuerydslLdapQuery<K> where(Predicate... o) {
+
+		if (o == null) {
+			return this;
+		}
+
 		return queryMixin.where(o);
 	}
 
 	@SuppressWarnings("unchecked")
 	public List<K> list() {
-		return (List<K>) ldapOperations.find(buildQuery(), entityType);
+
+		LdapQuery ldapQuery = buildQuery();
+		if (ldapQuery.filter() instanceof AbsoluteTrueFilter) {
+			return (List<K>) ldapOperations.findAll(entityType);
+		}
+
+		return (List<K>) ldapOperations.find(ldapQuery, entityType);
 	}
 
 	public K uniqueResult() {
 		return ldapOperations.findOne(buildQuery(), entityType);
 	}
 
-	private LdapQuery buildQuery() {
+	LdapQuery buildQuery() {
 
 		Predicate where = queryMixin.getMetadata().getWhere();
-		if (where != null) {
-			return query().filter(filterGenerator.handle(where));
-		}
-
-		return query();
+		return where != null ? query().filter(filterGenerator.handle(where)) : query().filter(new AbsoluteTrueFilter());
 	}
 }

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

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.ldap.repository.support;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.ldap.core.LdapOperations;
+import org.springframework.ldap.filter.AbsoluteTrueFilter;
+import org.springframework.ldap.filter.EqualsFilter;
+import org.springframework.ldap.odm.core.impl.DefaultObjectDirectoryMapper;
+import org.springframework.ldap.query.LdapQuery;
+
+/**
+ * Unit tests for {@link QuerydslLdapQuery}.
+ *
+ * @author Mark Paluch
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class QuerydslLdapQueryUnitTests {
+
+	@Mock LdapOperations ldapOperations;
+
+	@Before
+	public void before() {
+		when(ldapOperations.getObjectDirectoryMapper()).thenReturn(new DefaultObjectDirectoryMapper());
+	}
+
+	@Test // DATALDAP-65
+	public void shouldCreateFilter() {
+
+		QuerydslLdapQuery<UnitTestPerson> query = new QuerydslLdapQuery<>(ldapOperations, UnitTestPerson.class);
+
+		LdapQuery ldapQuery = query.where(QPerson.person.fullName.eq("foo")).buildQuery();
+
+		assertThat(ldapQuery.filter()).isInstanceOf(EqualsFilter.class);
+	}
+
+	@Test // DATALDAP-65
+	public void shouldCreateEmptyFilter() {
+
+		QuerydslLdapQuery<UnitTestPerson> query = new QuerydslLdapQuery<>(ldapOperations, UnitTestPerson.class);
+
+		LdapQuery ldapQuery = query.buildQuery();
+
+		assertThat(ldapQuery.filter()).isInstanceOf(AbsoluteTrueFilter.class);
+	}
+
+	@Test // DATALDAP-65
+	public void shouldCreateEmptyFilterFromWhereNull() {
+
+		QuerydslLdapQuery<UnitTestPerson> query = new QuerydslLdapQuery<>(ldapOperations, QPerson.person);
+
+		LdapQuery ldapQuery = query.where(null).buildQuery();
+
+		assertThat(ldapQuery.filter()).isInstanceOf(AbsoluteTrueFilter.class);
+	}
+}