querystring parser.

QS.java

package dev.kishibashi.common.module.querystring;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 *
 * @author kishibashi
 */
public class QS {

    private final Map<String, Object> map = new LinkedHashMap<>();

    public QS(final String query) {
        final Map<String, List<String>> tempMap = new LinkedHashMap<>();

        for (String keyValue: query.replaceFirst("^\\?", "").split("&")) {
            final String[] sp_1 = keyValue.split("=");
            final String key = sp_1[0];
            final String value = (sp_1.length >= 1) ? sp_1[1] : null;

            final String[] sp_2 = key.split("\\[|\\]");
            final String keyName = sp_2[0];
            final Integer index = (sp_2.length >= 1) ? Integer.parseInt(sp_2[1]) : null;
            if (!tempMap.containsKey(keyName)) {
                tempMap.put(keyName, new ArrayList<>());
            }
            final List<String> valueList = tempMap.get(keyName);
            if (index == null) {
                valueList.add(value);
                continue;
            }
            while (valueList.size() < index) {
                valueList.add(null);
            }
            valueList.add(index, value);
        }
        for (Map.Entry<String, List<String>> entry: tempMap.entrySet()) {
            final List<String> valueList = entry.getValue();
            final Object value = (valueList.size() >= 2) ? valueList : valueList.get(0);
            map.put(entry.getKey(), value);
        }
    }

    public Map<String, Object> toMap() {
        return map;
    }
}