QueryBuilder.java

/*
 * QueryBuilder.java October 2002
 *
 * Copyright (C) 2002, Niall Gallagher <niallg@users.sf.net>
 *
 * 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.simpleframework.http.core;

import static org.simpleframework.http.Protocol.APPLICATION;
import static org.simpleframework.http.Protocol.URL_ENCODED;

import org.simpleframework.http.ContentType;
import org.simpleframework.http.Query;
import org.simpleframework.http.Request;
import org.simpleframework.http.message.Entity;
import org.simpleframework.http.message.Header;

/**
 * The <code>QueryBuilder</code> object is used to create the query. It is
 * created using the request URI query and a form post body if sent. The
 * application/x-www-form-urlencoded conent type identifies the body as contain
 * form data. If there are duplicates then they both are available from the
 * query that is built.
 * 
 * @author Niall Gallagher
 */
class QueryBuilder {

    /**
     * This is the request that is used to acquire the data.
     */
    private final Request request;

    /**
     * This is the header that is used to acquire the data.
     */
    private final Header header;

    /**
     * Constructor for the <code>QueryBuilder</code> object. This will create an
     * object that can be used to construct a single query from the multiple
     * sources of data within the request entity.
     * 
     * @param request
     *            this is the request to build a query for
     * @param entity
     *            this is the entity that contains the data
     */
    public QueryBuilder(Request request, Entity entity) {
        this.header = entity.getHeader();
        this.request = request;
    }

    /**
     * This method is used to acquire the query part from the HTTP request URI
     * target and a form post if it exists. Both the query and the form post are
     * merge together in a single query.
     * 
     * @return the query associated with the HTTP target URI
     */
    public Query build() {
        ;
        Query query = this.header.getQuery();

        if (!this.isFormPost()) return query;
        return this.getQuery(query);
    }

    /**
     * This method is used to acquire the query part from the HTTP request URI
     * target and a form post if it exists. Both the query and the form post are
     * merge together in a single query.
     * 
     * @param query
     *            this is the URI query string to be used
     * 
     * @return the query associated with the HTTP target URI
     */
    private Query getQuery(Query query) {
        String body = this.getContent();

        if (body == null) return query;
        return new QueryCombiner(query, body);
    }

    /**
     * This method attempts to acquire the content of the request body. If there
     * is an <code>IOException</code> acquiring the content of the body then
     * this will simply return a null value without reporting the exception.
     * 
     * @return the content of the body, or null on error
     */
    private String getContent() {
        try {
            return this.request.getContent();
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * This is used to determine if the content type is a form POST of type
     * application/x-www-form-urlencoded. Such a type is used when a HTML form
     * is used to post data to the server.
     * 
     * @return this returns true if content type is a form post
     */
    private boolean isFormPost() {
        ContentType type = this.request.getContentType();

        if (type == null) return false;
        return this.isFormPost(type);
    }

    /**
     * This is used to determine if the content type is a form POST of type
     * application/x-www-form-urlencoded. Such a type is used when a HTML form
     * is used to post data to the server.
     * 
     * @param type
     *            the type to determine if its a form post
     * 
     * @return this returns true if content type is a form post
     */
    private boolean isFormPost(ContentType type) {
        String primary = type.getPrimary();
        String secondary = type.getSecondary();

        if (!primary.equals(APPLICATION)) return false;
        return secondary.equals(URL_ENCODED);
    }
}