[GitHub] [ignite] akuznetsov-gridgain commented on a change in pull request #7912: IGNITE-13133: Add support of QuerydslPredicateExecutor for ignite-spring-data

[GitBox <gi...@apache.org>]

akuznetsov-gridgain commented on a change in pull request #7912:
URL: https://github.com/apache/ignite/pull/7912#discussion_r437840896



##########
File path: modules/spring-data-2.0/src/main/java/org/apache/ignite/springdata20/repository/support/QueryPredicateExecutorImpl.java
##########
@@ -0,0 +1,205 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.ignite.springdata20.repository.support;
+
+import com.querydsl.core.types.OrderSpecifier;
+import com.querydsl.core.types.Predicate;
+import com.querydsl.sql.Configuration;
+import com.querydsl.sql.SQLSerializer;
+import com.querydsl.sql.SQLTemplates;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.query.QueryCursor;
+import org.apache.ignite.cache.query.SqlFieldsQuery;
+import org.apache.ignite.springdata20.repository.query.IgniteQuery;
+import org.apache.ignite.springdata20.repository.query.IgniteQueryGenerator;
+import org.apache.ignite.springdata20.repository.query.ReturnStrategy;
+import org.apache.ignite.springdata20.repository.query.QueryUtils;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageImpl;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.querydsl.QuerydslPredicateExecutor;
+import org.springframework.data.repository.core.RepositoryMetadata;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+
+import static java.util.stream.Collectors.toList;
+
+/**
+ * General Apache Ignite query predicate executor implementation.
+ * This bean shouldn't ever be loaded by context directly, only via {@link IgniteRepositoryFactory}
+ */
+public class QueryPredicateExecutorImpl<T> implements QuerydslPredicateExecutor<T> {
+    /** Config for SQL serializer. */
+    private final Configuration conf = new Configuration(SQLTemplates.DEFAULT);
+
+    /** Underlying cache to execute SQL queries. */
+    private final IgniteCache cache;
+
+    /** Result type. */
+    private final Class<?> type;
+
+    /**
+     * @param cache Cache.
+     * @param metadata Metadata.
+     */
+    public QueryPredicateExecutorImpl(IgniteCache cache, RepositoryMetadata metadata) {
+        this.cache = cache;
+        this.type = metadata.getDomainType();
+    }
+
+    /** {@inheritDoc} */
+    @Override public Optional<T> findOne(Predicate pred) {
+        return executeQuery(prepareSelectQuery(pred), PageRequest.of(0, 1)).stream().findFirst();
+    }
+
+    /** {@inheritDoc} */
+    @Override public Iterable<T> findAll(Predicate pred) {
+        return executeQuery(prepareSelectQuery(pred));
+    }
+
+    /** {@inheritDoc} */
+    @Override public Iterable<T> findAll(Predicate pred, Sort sort) {
+        return executeQuery(prepareSelectQuery(pred), sort);
+    }
+
+    /** {@inheritDoc} */
+    @Override public Iterable<T> findAll(Predicate pred, OrderSpecifier<?>... orders) {
+        Sort sort = Sort.by(mapQryDslOrderSpecifiersToOrders(orders));
+
+        return executeQuery(prepareSelectQuery(pred), sort);
+    }
+
+    /** {@inheritDoc} */
+    @Override public Iterable<T> findAll(OrderSpecifier<?>... orders) {
+        Sort sort = Sort.by(mapQryDslOrderSpecifiersToOrders(orders));
+
+        return executeQuery(prepareSqlQuery("SELECT * FROM " + type.getSimpleName()), sort);
+    }
+
+    /** {@inheritDoc} */
+    @Override public Page<T> findAll(Predicate pred, Pageable pageable) {
+        return new PageImpl<>(executeQuery(prepareSelectQuery(pred), pageable), pageable, 0);
+    }
+
+    /** {@inheritDoc} */
+    @Override public long count(Predicate pred) {
+        SQLSerializer ser = prepareSqlQuery("SELECT COUNT(*) FROM " + type.getSimpleName() + " WHERE ", pred);
+
+        SqlFieldsQuery qry = new SqlFieldsQuery(ser.toString());
+        qry.setArgs(ser.getConstants().toArray());
+
+        List<List<?>> res = cache.query(qry).getAll();
+
+        return (Long) res.get(0).get(0);
+    }
+
+    /** {@inheritDoc} */
+    @Override public boolean exists(Predicate pred) {
+        return !executeQuery(prepareSelectQuery(pred), PageRequest.of(0, 1)).isEmpty();
+    }
+
+    /**
+     * @param pred Predicate.
+     * @return Prepared sql serializer.
+     */
+    private SQLSerializer prepareSelectQuery(Predicate pred) {
+        return prepareSqlQuery(
+            "SELECT * FROM " + type.getSimpleName() + " WHERE ",
+            pred
+        );
+    }
+
+    /**
+     * @param selectPart Select part.
+     * @return Prepared sql serializer.
+     */
+    private SQLSerializer prepareSqlQuery(String selectPart) {
+        return prepareSqlQuery(selectPart, null);
+    }
+
+    /**
+     * @param selectPart Select partition.
+     * @param pred Predicate.
+     * @return Prepared sql serializer.
+     */
+    private SQLSerializer prepareSqlQuery(String selectPart, Predicate pred) {
+        SQLSerializer res = new SQLSerializer(conf).append(selectPart + " ");
+
+        if (pred != null)
+            return res.handle(pred);
+
+        return res;
+    }
+
+    /**
+     * @param ser Serializable.
+     * @param additionalParams Additional params.
+     * @return List of results.
+     */
+    @SuppressWarnings({"unchecked", "rawtypes"})
+    private List<T> executeQuery(SQLSerializer ser, Object... additionalParams) {
+        List<Object> params = ser.getConstants();
+        params.addAll(Arrays.asList(additionalParams));
+
+        Object[] arrParams = params.toArray();
+
+        IgniteQuery qry = IgniteQueryGenerator.prepareQuery(type, ser.toString(), arrParams);
+
+        QueryCursor qryCursor = cache.query(QueryUtils.prepareQuery(qry, arrParams));
+
+        return (List<T>) QueryUtils.transformQueryCursor(qryCursor, arrParams, false, ReturnStrategy.LIST_OF_VALUES);

Review comment:
       I think you qryCursor should be wrapped with try-with-resource in order to close cursor after query execution.




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