/*
* Copyright 2014-2016 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.keyvalue.core;
import java.io.Serializable;
import java.util.Collection;
import org.springframework.data.keyvalue.core.query.KeyValueQuery;
/**
* Base implementation for accessing and executing {@link KeyValueQuery} against a {@link KeyValueAdapter}.
*
* @author Christoph Strobl
* @param <ADAPTER>
* @param <CRITERIA>
* @param <SORT>
*/
public abstract class QueryEngine<ADAPTER extends KeyValueAdapter, CRITERIA, SORT> {
private final CriteriaAccessor<CRITERIA> criteriaAccessor;
private final SortAccessor<SORT> sortAccessor;
private ADAPTER adapter;
public QueryEngine(CriteriaAccessor<CRITERIA> criteriaAccessor, SortAccessor<SORT> sortAccessor) {
this.criteriaAccessor = criteriaAccessor;
this.sortAccessor = sortAccessor;
}
/**
* Extract query attributes and delegate to concrete execution.
*
* @param query
* @param keyspace
* @return
*/
public Collection<?> execute(KeyValueQuery<?> query, Serializable keyspace) {
CRITERIA criteria = this.criteriaAccessor != null ? this.criteriaAccessor.resolve(query) : null;
SORT sort = this.sortAccessor != null ? this.sortAccessor.resolve(query) : null;
return execute(criteria, sort, query.getOffset(), query.getRows(), keyspace);
}
/**
* Extract query attributes and delegate to concrete execution.
*
* @param query
* @param keyspace
* @return
*/
public <T> Collection<T> execute(KeyValueQuery<?> query, Serializable keyspace, Class<T> type) {
CRITERIA criteria = this.criteriaAccessor != null ? this.criteriaAccessor.resolve(query) : null;
SORT sort = this.sortAccessor != null ? this.sortAccessor.resolve(query) : null;
return execute(criteria, sort, query.getOffset(), query.getRows(), keyspace, type);
}
/**
* Extract query attributes and delegate to concrete execution.
*
* @param query
* @param keyspace
* @return
*/
public long count(KeyValueQuery<?> query, Serializable keyspace) {
CRITERIA criteria = this.criteriaAccessor != null ? this.criteriaAccessor.resolve(query) : null;
return count(criteria, keyspace);
}
/**
* @param criteria
* @param sort
* @param offset
* @param rows
* @param keyspace
* @return
*/
public abstract Collection<?> execute(CRITERIA criteria, SORT sort, long offset, int rows, Serializable keyspace);
/**
* @param criteria
* @param sort
* @param offset
* @param rows
* @param keyspace
* @param type
* @return
* @since 1.1
*/
public <T> Collection<T> execute(CRITERIA criteria, SORT sort, long offset, int rows, Serializable keyspace,
Class<T> type) {
return (Collection<T>) execute(criteria, sort, offset, rows, keyspace);
}
/**
* @param criteria
* @param keyspace
* @return
*/
public abstract long count(CRITERIA criteria, Serializable keyspace);
/**
* Get the {@link KeyValueAdapter} used.
*
* @return
*/
protected ADAPTER getAdapter() {
return this.adapter;
}
/**
* @param adapter
*/
@SuppressWarnings("unchecked")
public void registerAdapter(KeyValueAdapter adapter) {
if (this.adapter == null) {
this.adapter = (ADAPTER) adapter;
} else {
throw new IllegalArgumentException("Cannot register more than one adapter for this QueryEngine.");
}
}
}