org.silverpeas.servlet.RequestParameterDecoder.java Source code

Introduction

Here is the source code for org.silverpeas.servlet.RequestParameterDecoder.java

Source

/*
 * Copyright (C) 2000 - 2014 Silverpeas
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * As a special exception to the terms and conditions of version 3.0 of
 * the GPL, you may redistribute this Program in connection with Free/Libre
 * Open Source Software ("FLOSS") applications as described in Silverpeas's
 * FLOSS exception. You should have recieved a copy of the text describing
 * the FLOSS exception, and it is also available here:
 * "http://www.silverpeas.org/docs/core/legal/floss_exception.html"
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.silverpeas.servlet;

import com.silverpeas.util.StringUtil;
import org.apache.commons.lang.NotImplementedException;

import javax.servlet.ServletRequest;
import javax.ws.rs.FormParam;
import java.lang.reflect.Field;
import java.util.Date;

/**
 * This class decodes the request parameters in order to set them to a simple specified POJO which
 * attributes are annotated by {@link javax.ws.rs.FormParam} annotation.
 * WARNING : for now, the decoder is not compatible with Inner Classes.
 * @author: Yohann Chastagnier
 */
public class RequestParameterDecoder {

    // Singleton (Could be useful for Unit Tests)
    private static final RequestParameterDecoder decoder = new RequestParameterDecoder();

    /**
     * Gets the singleton instance.
     * @return
     */
    protected static RequestParameterDecoder getInstance() {
        return decoder;
    }

    /**
     * Decodes the request parameters in order to return an object filled with their values.
     * @param request the {@link ServletRequest} that will be wrapped by {@link HttpRequest}
     * @param objectClass the class of the requested returned instance.
     * @param <OBJECT> the type of the requested returned instance.
     * @return
     */
    public static <OBJECT> OBJECT decode(ServletRequest request, Class<OBJECT> objectClass) {
        return decode(HttpRequest.decorate(request), objectClass);
    }

    /**
     * Decodes the request parameters in order to return an object filled with their values.
     * @param request the {@link HttpRequest} wrapper that handle efficiently all parameters,
     * included
     * those of multipart request type.
     * @param objectClass the class of the requested returned instance.
     * @param <OBJECT> the type of the requested returned instance.
     * @return
     */
    public static <OBJECT> OBJECT decode(HttpRequest request, Class<OBJECT> objectClass) {
        return getInstance()._decode(request, objectClass);
    }

    /**
     * The private implementation.
     */
    private <OBJECT> OBJECT _decode(HttpRequest request, Class<OBJECT> objectClass) {
        try {

            // New instance
            OBJECT newInstance = objectClass.newInstance();

            // Reading all class fields.
            for (Field field : objectClass.getDeclaredFields()) {
                // Is existing the FormParam annotation ?
                FormParam param = field.getAnnotation(FormParam.class);
                if (param != null) {
                    boolean isAccessible = field.isAccessible();
                    if (!isAccessible) {
                        field.setAccessible(true);
                    }
                    field.set(newInstance,
                            getParameterValue(request,
                                    StringUtil.isDefined(param.value()) ? param.value() : field.getName(),
                                    field.getType()));
                    if (!isAccessible) {
                        field.setAccessible(false);
                    }
                }
            }

            // Instance is set.
            // Returning it.
            return newInstance;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Gets the parameter value according to the type of the specified field.
     * @param request
     * @param parameterName
     * @param parameterClass
     * @return
     * @throws Exception
     */
    private Object getParameterValue(HttpRequest request, String parameterName, Class<?> parameterClass)
            throws Exception {
        final Object value;
        if (parameterClass.isAssignableFrom(RequestFile.class)) {
            value = request.getParameterAsRequestFile(parameterName);
        } else if (parameterClass.isAssignableFrom(String.class)) {
            value = request.getParameter(parameterName);
        } else if (parameterClass.isAssignableFrom(Long.class)) {
            value = request.getParameterAsLong(parameterName);
        } else if (parameterClass.getName().equals("long")) {
            value = request.getParameterAsLong(parameterName);
        } else if (parameterClass.isAssignableFrom(Integer.class)) {
            value = request.getParameterAsInteger(parameterName);
        } else if (parameterClass.getName().equals("int")) {
            value = request.getParameterAsInteger(parameterName);
        } else if (parameterClass.isAssignableFrom(Date.class)) {
            value = request.getParameterAsDate(parameterName);
        } else if (parameterClass.isAssignableFrom(Boolean.class)) {
            value = request.getParameterAsBoolean(parameterName);
        } else if (parameterClass.getName().equals("boolean")) {
            value = request.getParameterAsBoolean(parameterName);
        } else {
            throw new NotImplementedException("The type " + parameterClass.getName() + " is not handled...");
        }
        return value;
    }
}