/*
* Copyright 2011-2015 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.hadoop.hive;
import java.sql.SQLException;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.InvalidDataAccessResourceUsageException;
import org.springframework.dao.TypeMismatchDataAccessException;
import org.springframework.dao.UncategorizedDataAccessException;
import org.springframework.dao.support.DataAccessUtils;
import org.springframework.util.Assert;
import org.springframework.util.ResourceUtils;
/**
* Helper class that simplifies Hive data access code. Automatically handles the creation of a {@link HiveClient}
* and converts Hive exceptions into DataAccessExceptions.
*
* @author Costin Leau
* @author Thomas Risberg
*/
public class HiveTemplate implements InitializingBean, HiveOperations, ResourceLoaderAware {
private HiveClientFactory hiveClientFactory;
private ResourceLoader resourceLoader;
/**
* Constructs a new <code>HiveClient</code> instance.
* Expects {@link #setHiveClientFactory(HiveClientFactory)} to be called before using it.
*/
public HiveTemplate() {
}
/**
* Constructs a new <code>HiveTemplate</code> instance.
*
* @param hiveClientFactory HiveClient factory
*/
public HiveTemplate(HiveClientFactory hiveClientFactory) {
this.hiveClientFactory = hiveClientFactory;
afterPropertiesSet();
}
@Override
public void afterPropertiesSet() {
Assert.notNull(hiveClientFactory, "non-null hive client factory required");
}
/**
* Executes the action specified by the given callback object within an active connection.
*
* @param action callback object that specifies the Hive action
* @return the action result object
* @throws DataAccessException exception
*/
@Override
public <T> T execute(HiveClientCallback<T> action) throws DataAccessException {
Assert.notNull(action, "a valid callback is required");
HiveClient hiveClient = createHiveClient();
try {
return action.doInHive(hiveClient);
} catch (Exception ex) {
throw convertHiveAccessException(ex);
} finally {
try {
hiveClient.shutdown();
} catch (Exception ex) {
throw new InvalidDataAccessResourceUsageException("Error while closing client connection", ex);
}
}
}
/**
* Converts the given Hive exception to an appropriate exception from the <tt>org.springframework.dao</tt> hierarchy.
*
* @param ex hive exception
* @return a corresponding DataAccessException
*/
protected DataAccessException convertHiveAccessException(Exception ex) {
return HiveUtils.convert(ex);
}
/**
* Executes the given HiveQL that results in a list of objects.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @return list of values returned by the query
* @throws DataAccessException exception
*/
@Override
public List<String> query(String query) throws DataAccessException {
return query(query, null);
}
/**
* Executes the given HiveQL using the list of arguments, expecting a list of objects.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @param arguments query arguments
* @return list of values returned by the query
* @throws DataAccessException exception
*/
@Override
public List<String> query(String query, Map<?, ?> arguments) throws DataAccessException {
Assert.hasText(query, "a script is required");
Resource res = null;
if (ResourceUtils.isUrl(query)) {
if (resourceLoader != null) {
res = resourceLoader.getResource(query);
}
}
else {
res = new ByteArrayResource(query.getBytes());
}
return executeScript(new HiveScript(res, arguments));
}
/**
* Executes the given HiveQL that results in a single object.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @return query result
* @throws DataAccessException exception
*/
@Override
public String queryForString(String query) throws DataAccessException {
return queryForString(query, null);
}
/**
* Executes the given HiveQL using the list of arguments, that results in a single object.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @param arguments query arguments
* @return query result
* @throws DataAccessException exception
*/
@Override
public String queryForString(String query, Map<?, ?> arguments) throws DataAccessException {
return DataAccessUtils.singleResult(query(query, arguments));
}
/**
* Executes the given HiveQL that results in a single int value.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @return query int result
* @throws DataAccessException exception
*/
@Override
public Integer queryForInt(String query) throws DataAccessException {
return queryForInt(query, null);
}
/**
* Executes the given HiveQL using the list of arguments, that results in a single int value.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @param arguments query arguments
* @return query int result
* @throws DataAccessException exception
*/
@Override
public Integer queryForInt(String query, Map<?, ?> arguments) throws DataAccessException {
String result = queryForString(query, arguments);
if (result != null) {
try {
return Integer.valueOf(result);
} catch (NumberFormatException ex) {
throw new TypeMismatchDataAccessException("Invalid int result found [" + result + "]", ex);
}
}
return null;
}
/**
* Executes the given HiveQL that results in a single long value.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @return query long result
* @throws DataAccessException exception
*/
@Override
public Long queryForLong(String query) throws DataAccessException {
return queryForLong(query, null);
}
/**
* Executes the given HiveQL using the list of arguments, that results in a single long value.
* The script is interpreted as a URL or if that fails, as a HiveQL statement.
*
* @param query HiveQL
* @param arguments query arguments
* @return query long result
* @throws DataAccessException exception
*/
@Override
public Long queryForLong(String query, Map<?, ?> arguments) throws DataAccessException {
String result = queryForString(query, arguments);
if (result != null) {
try {
return Long.valueOf(result);
} catch (NumberFormatException ex) {
throw new TypeMismatchDataAccessException("Invalid long result found [" + result + "]", ex);
}
}
return null;
}
/**
* Executes a Hive script.
*
* @param script script resource and arguments
* @return script result
* @throws DataAccessException exception
*/
@Override
public List<String> executeScript(HiveScript script) throws DataAccessException {
return executeScript(Collections.singleton(script));
}
/**
* Executes multiple Hive scripts.
*
* @param scripts scripts resources and arguments
* @return scripts results
* @throws DataAccessException exception
*/
@Override
public List<String> executeScript(final Iterable<HiveScript> scripts) throws DataAccessException {
return execute(new HiveClientCallback<List<String>>() {
@Override
public List<String> doInHive(HiveClient hiveClient) throws Exception {
return HiveUtils.run(hiveClient, scripts);
}
});
}
protected HiveClient createHiveClient() {
return hiveClientFactory.getHiveClient();
}
/**
* Sets the {@link HiveClient} factory.
*
* @param hiveClientFactory hive client factory to set
*/
public void setHiveClientFactory(HiveClientFactory hiveClientFactory) {
this.hiveClientFactory = hiveClientFactory;
}
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
}