/*
* 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.jena.arq.querybuilder.handlers;
import java.io.ByteArrayInputStream ;
import java.util.List ;
import java.util.Map ;
import org.apache.jena.arq.querybuilder.Order;
import org.apache.jena.arq.querybuilder.rewriters.ExprRewriter ;
import org.apache.jena.graph.Node ;
import org.apache.jena.query.Query ;
import org.apache.jena.query.SortCondition ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.core.VarExprList ;
import org.apache.jena.sparql.expr.Expr ;
import org.apache.jena.sparql.expr.ExprList ;
import org.apache.jena.sparql.expr.ExprVar ;
import org.apache.jena.sparql.lang.sparql_11.ParseException ;
import org.apache.jena.sparql.lang.sparql_11.SPARQLParser11 ;
/**
* The Solution Modifier handler.
*
*/
public class SolutionModifierHandler implements Handler {
// the query to modify
private final Query query;
/**
* Constructor
* @param query The query to modify.
*/
public SolutionModifierHandler(Query query) {
this.query = query;
}
/**
* Copy all the modifications from the Solution Modifier argument
* @param solutionModifier The solution modifier to copy from.
*/
public void addAll(SolutionModifierHandler solutionModifier) {
List<SortCondition> lst = solutionModifier.query.getOrderBy();
if (lst != null) {
for (SortCondition sc : lst) {
query.addOrderBy(sc);
}
}
query.getGroupBy().addAll(solutionModifier.query.getGroupBy());
query.getHavingExprs().addAll(solutionModifier.query.getHavingExprs());
query.setLimit(solutionModifier.query.getLimit());
query.setOffset(solutionModifier.query.getOffset());
}
/**
* Add an order by clause
* @param condition The SortCondition to add to the order by.
*/
public void addOrderBy(SortCondition condition) {
query.addOrderBy(condition);
}
/**
* Add an expression to the order by clause.
* Sorts in Default order.
* @param expr The expression to add.
*/
public void addOrderBy(Expr expr) {
query.addOrderBy(expr, Query.ORDER_DEFAULT);
}
/**
* Add an expression to the order by clause.
* @param expr The expression to add.
* @param order The direction of the ordering.
*/
public void addOrderBy(Expr expr, Order order) {
query.addOrderBy(expr, order == Order.ASCENDING ? Query.ORDER_ASCENDING
: Query.ORDER_DESCENDING);
}
/**
* Add a var to the order by clause.
* Sorts in default order
* @param var The var to use for sorting
*/
public void addOrderBy(Var var) {
query.addOrderBy(var, Query.ORDER_DEFAULT);
}
/**
* Add a var to the order by clause.
* @param var The var to sort by.
* @param order The direction of the ordering.
*/
public void addOrderBy(Var var, Order order) {
query.addOrderBy(var, order == Order.ASCENDING ? Query.ORDER_ASCENDING
: Query.ORDER_DESCENDING);
}
/**
* Add an expression to the group by clause.
* @param expr The expression to add.
*/
public void addGroupBy(Expr expr) {
query.addGroupBy(expr);
}
/**
* Add a node to the group by clause.
* @param var The variable to add.
*/
public void addGroupBy(Var var) {
query.addGroupBy(var);
}
/**
* Add var and expression to the group by clause.
* @param var The variable to add.
* @param expr The expression to add.
*/
public void addGroupBy(Var var, Expr expr) {
query.addGroupBy(var, expr);
}
/**
* Add a having expression.
* @param expression The expression to add
* @throws ParseException If the expression can not be parsed.
*/
public void addHaving(String expression) throws ParseException {
String havingClause = "HAVING (" + expression + " )";
SPARQLParser11 parser = new SPARQLParser11(new ByteArrayInputStream(
havingClause.getBytes()));
parser.setQuery(query);
parser.HavingClause();
}
/**
* Add a variable to the having clause.
* @param var The variable to add.
*/
public void addHaving(Var var) {
query.addHavingCondition(new ExprVar(var));
}
/**
* Add an expression to the having clause.
* @param expr The expression to add.
*/
public void addHaving(Expr expr) {
query.addHavingCondition(expr);
}
/**
* Set the limit for the number of results to return.
* Setting the limit to zero (0) or removes the limit.
* @param limit THe limit to set.
*/
public void setLimit(int limit) {
query.setLimit(limit < 1 ? Query.NOLIMIT : limit);
}
/**
* Set the offset for the results to return.
* Setting the offset to zero (0) or removes the offset.
* @param offset THe offset to set.
*/
public void setOffset(int offset) {
query.setOffset(offset < 1 ? Query.NOLIMIT : offset);
}
@Override
public void setVars(Map<Var, Node> values) {
if (values.isEmpty()) {
return;
}
ExprRewriter exprRewriter = new ExprRewriter(values);
ExprList having = exprRewriter.rewrite(new ExprList(query
.getHavingExprs()));
List<SortCondition> orderBy = exprRewriter
.rewriteSortConditionList(query.getOrderBy());
VarExprList groupBy = exprRewriter.rewrite(query.getGroupBy());
query.getHavingExprs().clear();
query.getHavingExprs().addAll(having.getList());
if (orderBy != null) {
if (query.getOrderBy() == null) {
for (SortCondition sc : orderBy) {
query.addOrderBy(sc);
}
} else {
query.getOrderBy().clear();
query.getOrderBy().addAll(orderBy);
}
}
query.getGroupBy().clear();
query.getGroupBy().addAll(groupBy);
}
@Override
public void build() {
// no special commands.
}
}