/*
* Copyright 2014 Red Hat, Inc. and/or its affiliates.
*
* 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.dashbuilder.dataset.engine.sort;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import org.dashbuilder.comparator.ComparatorUtils;
import org.dashbuilder.dataset.DataColumn;
import org.dashbuilder.dataset.sort.SortOrder;
/**
* A comparator of data set rows.
*/
public class DataSetRowComparator implements Comparator<Integer> {
protected List<DataColumn> columns = new ArrayList<DataColumn>();
protected List<SortOrder> orders = new ArrayList<SortOrder>();
public DataSetRowComparator criteria(DataColumn column, SortOrder order) {
columns.add(column);
orders.add(order);
return this;
}
public int compare(Integer row1, Integer row2) {
// Check criteria.
if (columns.isEmpty()) return 0;
// Objects must be not null arrays.
if (row1 == null && row2 != null) return -1;
else if (row1 != null && row2 == null) return 1;
else if (row1 == null) return 0;
// Compare the two rows.
for (int i=0; i<columns.size(); i++) {
DataColumn column = columns.get(i);
SortOrder order = orders.get(i);
Comparable value1 = (Comparable) column.getValues().get(row1);
Comparable value2 = (Comparable) column.getValues().get(row2);
int comp = ComparatorUtils.compare(value1, value2, order.asInt());
if (comp != 0) return comp;
}
return 0;
}
}