core/src/main/java/de/ids_mannheim/korap/web/utils/FormRequestWrapper.java

package de.ids_mannheim.korap.web.utils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.ws.rs.core.MultivaluedMap;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

/**
 * Helper class to wrapp multivaluedmap into a hashmap. Depending on
 * the strict parameter,
 * list values are retained in the resulting wrapper map.
 * 
 * @author hanl
 * @date 25/04/2015
 */
public class FormRequestWrapper extends HttpServletRequestWrapper {

    private MultivaluedMap<String, Object> form;


    /**
     * Constructs a request object wrapping the given request.
     * 
     * @param request
     * @throws IllegalArgumentException
     *             if the request is null
     */
    public FormRequestWrapper (HttpServletRequest request,
                               MultivaluedMap<String, Object> form) {
        super(request);
        this.form = form;
    }


    @Override
    public String getParameter (String name) {
        String value = super.getParameter(name);
        if (value == null)
            value = String.valueOf(form.getFirst(name));
        return value;
    }


    @Override
    public String[] getParameterValues (String name) {
        String[] values = super.getParameterValues(name);
        if (values == null && form.get(name) != null) {
            values = new String[form.get(name).size()];
            values = form.get(name).toArray(values);
        }
        return values;
    }


    public Map<String, Object> singleValueMap () {
        return toMap(this.form, false);
    }


    /**
     * @param strict
     *            returns only values with size equal to one. If false
     *            pairs key to first value
     *            in value list and returns the result
     * @return key/value map
     */
    public static Map<String, Object> toMap (
            MultivaluedMap<String, Object> form, boolean strict) {
        if (form == null)
            return null;
        HashMap<String, Object> map = new HashMap<>();
        for (String key : form.keySet()) {
            if (strict && form.get(key).size() > 1)
                continue;
            map.put(key, form.getFirst(key));

        }
        return map;
    }


    public void put (String key, String value) {
        this.form.putSingle(key, value);
    }


    public void put (String key, String ... values) {
        this.form.put(key, Arrays.<Object> asList(values));
    }

}