DATACOUCH-156 - Make generated N1QL queries filter on the type field.

The generated N1QL queries currently don't filter on the type at all.

Add a criteria to the WHERE clause that checks the field holding type information is matching the entity fully qualified class name.

Add a placeholder for inline N1QL queries that can be replaced by the same type information criteria.

src/main/java/org/springframework/data/couchbase/core/convert/CouchbaseConverter.java

@@ -51,4 +51,9 @@ public interface CouchbaseConverter
    * @see #convertForWriteIfNeeded(Object)
    */
   Class<?> getWriteClassFor(Class<?> clazz);
+
+  /**
+   * @return the name of the field that will hold type information.
+   */
+  String getTypeKey();
 }

src/main/java/org/springframework/data/couchbase/core/convert/MappingCouchbaseConverter.java

@@ -130,9 +130,7 @@ public class MappingCouchbaseConverter extends AbstractCouchbaseConverter
     return mappingContext;
   }
 
-  /**
-   * @return the name of the field that will hold type information.
-   */
+  @Override
   public String getTypeKey() {
     return typeMapper.getTypeKey();
   }

src/main/java/org/springframework/data/couchbase/repository/query/N1qlQueryCreator.java

@@ -16,6 +16,7 @@
 
 package org.springframework.data.couchbase.repository.query;
 
+import static com.couchbase.client.java.query.dsl.Expression.i;
 import static com.couchbase.client.java.query.dsl.Expression.s;
 import static com.couchbase.client.java.query.dsl.Expression.x;
 
@@ -93,12 +94,14 @@ public class N1qlQueryCreator extends AbstractQueryCreator<LimitPath, Expression
 
   private final WherePath selectFrom;
   private final CouchbaseConverter converter;
+  private final CouchbaseQueryMethod queryMethod;
 
   public N1qlQueryCreator(PartTree tree, ParameterAccessor parameters, WherePath selectFrom,
-                          CouchbaseConverter converter) {
+                          CouchbaseConverter converter, CouchbaseQueryMethod queryMethod) {
     super(tree, parameters);
     this.selectFrom = selectFrom;
     this.converter = converter;
+    this.queryMethod = queryMethod;
   }
 
   @Override
@@ -122,6 +125,16 @@ public class N1qlQueryCreator extends AbstractQueryCreator<LimitPath, Expression
 
   @Override
   protected LimitPath complete(Expression criteria, Sort sort) {
+    //add part that filters on type key
+    String typeKey = converter.getTypeKey();
+    String typeValue = queryMethod.getEntityInformation().getJavaType().getName();
+    Expression typeSelector = i(typeKey).eq(s(typeValue));
+    if (criteria == null) {
+      criteria = typeSelector;
+    } else {
+      criteria = criteria.and(typeSelector);
+    }
+
     OrderByPath selectFromWhere = selectFrom.where(criteria);
 
     if (sort != null) {

src/main/java/org/springframework/data/couchbase/repository/query/PartTreeN1qlBasedQuery.java

@@ -61,7 +61,8 @@ public class PartTreeN1qlBasedQuery extends AbstractN1qlBasedQuery {
     }
     WherePath selectFrom = select.from(bucket);
 
-    N1qlQueryCreator queryCreator = new N1qlQueryCreator(partTree, accessor, selectFrom, getCouchbaseOperations().getConverter());
+    N1qlQueryCreator queryCreator = new N1qlQueryCreator(partTree, accessor, selectFrom,
+        getCouchbaseOperations().getConverter(), getQueryMethod());
     LimitPath selectFromWhereOrderBy = queryCreator.createQuery();
 
     if (partTree.isLimiting()) {

src/main/java/org/springframework/data/couchbase/repository/query/StringN1qlBasedQuery.java

@@ -52,18 +52,29 @@ public class StringN1qlBasedQuery extends AbstractN1qlBasedQuery {
    */
   public static final String PLACEHOLDER_ENTITY = "$ENTITY$";
 
+  /**
+   * Use this placeholder in a {@link org.springframework.data.couchbase.core.view.Query @Query} annotation's inline
+   * statement WHERE clause. This will be replaced by the expression allowing to only select documents matching the
+   * entity's class.
+   */
+  public static final String PLACEHOLDER_FILTER_TYPE = "$FILTER_TYPE$";
+
   private final Statement statement;
 
   public StringN1qlBasedQuery(String statement, CouchbaseQueryMethod queryMethod, CouchbaseOperations couchbaseOperations) {
     super(queryMethod, couchbaseOperations);
-    this.statement = prepare(statement, couchbaseOperations.getCouchbaseBucket().name());
+    String typeField = getCouchbaseOperations().getConverter().getTypeKey();
+    Class<?> typeValue = getQueryMethod().getEntityInformation().getJavaType();
+    this.statement = prepare(statement, couchbaseOperations.getCouchbaseBucket().name(), typeField, typeValue);
   }
 
-  protected static Statement prepare(String statement, String bucketName) {
+  protected static Statement prepare(String statement, String bucketName, String typeField, Class<?> typeValue) {
     String b = "`" + bucketName + "`";
     String entity = "META(" + b + ").id AS " + CouchbaseOperations.SELECT_ID +
         ", META(" + b + ").cas AS " + CouchbaseOperations.SELECT_CAS;
     String selectEntity = "SELECT " + entity + ", " + b + ".* FROM " + b;
+    String typeSelection = "`" + typeField + "` = \"" + typeValue.getName() + "\"";
+
     String result = statement;
     if (statement.contains(PLACEHOLDER_SELECT_FROM)) {
       result = result.replaceFirst("\\$SELECT_ENTITY\\$", selectEntity);
@@ -75,6 +86,11 @@ public class StringN1qlBasedQuery extends AbstractN1qlBasedQuery {
         result = result.replaceFirst("\\$ENTITY\\$", entity);
       }
     }
+
+    if (statement.contains(PLACEHOLDER_FILTER_TYPE)) {
+      result = result.replaceFirst("\\$FILTER_TYPE\\$", typeSelection);
+    }
+
     return Query.simple(result).statement();
   }