package com.ctp.cdi.query.builder;
import java.text.MessageFormat;
import java.util.List;
import javax.persistence.LockModeType;
import javax.persistence.Query;
import com.ctp.cdi.query.handler.QueryInvocationContext;
import com.ctp.cdi.query.param.Parameters;
import java.lang.reflect.Method;
/**
* Query builder factory. Delegates to concrete implementations.
*
* @author thomashug
*/
public abstract class QueryBuilder {
public static final String QUERY_SELECT = "select e from {0} e";
public static final String QUERY_COUNT = "select count(e) from {0} e";
public static final String ENTITY_NAME = "e";
public static String selectQuery(String entityName) {
return MessageFormat.format(QUERY_SELECT, entityName);
}
public static String countQuery(String entityName) {
return MessageFormat.format(QUERY_COUNT, entityName);
}
public abstract Object execute(QueryInvocationContext ctx) throws Exception;
protected boolean returnsList(Method method) {
return method.getReturnType().isAssignableFrom(List.class);
}
protected LockModeType extractLockMode(Method method) {
Class<com.ctp.cdi.query.Query> query = com.ctp.cdi.query.Query.class;
if (method.isAnnotationPresent(query) &&
method.getAnnotation(query).lock() != LockModeType.NONE) {
return method.getAnnotation(query).lock();
}
return null;
}
protected boolean hasLockMode(Method method) {
return extractLockMode(method) != null;
}
protected Query applyRestrictions(QueryInvocationContext context, Query query) {
Parameters params = context.getParams();
Method method = context.getMethod();
if (params.hasSizeRestriction()) {
query.setMaxResults(params.getSizeRestriciton());
}
if (params.hasFirstResult()) {
query.setFirstResult(params.getFirstResult());
}
if (hasLockMode(method)) {
query.setLockMode(extractLockMode(method));
}
return query;
}
}