QueryCombiner.java

/*
 * QueryCombiner.java May 2003
 *
 * Copyright (C) 2003, 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 java.util.List;
import java.util.Set;

import org.simpleframework.http.Query;
import org.simpleframework.http.parse.QueryParser;

/**
 * The <code>QueryCombimer</code> is used to parse several strings as a complete
 * URL encoded parameter string. This will do the following concatenations.
 * 
 * <pre>
 * null + "a=b&c=d&e=f" = "a=b&c=d&e=f"
 * "a=b" + "e=f&g=h" = "a=b&e=f&g=h";
 * "a=b&c=d&e=f" + "" = "a=b&c=d&e=f"
 * </pre>
 * 
 * This ensures that the <code>QueryForm</code> can parse the list of strings as
 * a single URL encoded parameter string. This can parse any number of parameter
 * strings.
 * 
 * @author Niall Gallagher
 */
class QueryCombiner extends QueryParser {

    /**
     * Constructor that allows a list of string objects to be parsed as a single
     * parameter string. This will check each string to see if it is empty, that
     * is, is either null or the zero length string.
     * 
     * @param list
     *            this is a list of query values to be used
     */
    public QueryCombiner(String... list) {
        this.parse(list);
    }

    /**
     * Constructor that allows an array of string objects to be parsed as a
     * single parameter string. This will check each string to see if it is
     * empty, that is, is either null or the zero length string.
     * 
     * @param query
     *            this is the query from the HTTP header
     * @param list
     *            this is the list of strings to be parsed
     */
    public QueryCombiner(Query query, String... list) {
        this.add(query);
        this.parse(list);
    }

    /**
     * Constructor that allows an array of string objects to be parsed as a
     * single parameter string. This will check each string to see if it is
     * empty, that is, is either null or the zero length string.
     * 
     * @param query
     *            this is the query from the HTTP header
     * @param post
     *            this is the query from the HTTP post body
     */
    public QueryCombiner(Query query, Query post) {
        this.add(query);
        this.add(post);
    }

    /**
     * This will concatenate the list of parameter strings as a single parameter
     * string, before handing it to be parsed by the <code>parse(String)</code>
     * method. This method will ignore any null or zero length strings in the
     * array.
     * 
     * @param list
     *            this is the list of strings to be parsed
     */
    public void parse(String[] list) {
        StringBuilder text = new StringBuilder();

        for (int i = 0; i < list.length; i++) {
            if (list[i] == null) {
                continue;
            } else if (list[i].length() == 0) {
                continue;
            } else if (text.length() > 0) {
                text.append("&");
            }
            text.append(list[i]);
        }
        this.parse(text);
    }

    /**
     * This is used to perform a parse of the form data that is in the provided
     * string builder. This will simply convert the data in to a string and
     * parse it in the normal fashion.
     * 
     * @param text
     *            this is the buffer to be converted to a string
     */
    private void parse(StringBuilder text) {
        if (text != null) {
            this.ensureCapacity(text.length());
            this.count = text.length();
            text.getChars(0, this.count, this.buf, 0);
            this.parse();
        }
    }

    /**
     * This method is used to insert a collection of tokens into the parsers
     * map. This is used when another source of tokens is required to populate
     * the connection currently maintained within this parsers internal map. Any
     * tokens that currently exist with similar names will be overwritten by
     * this.
     * 
     * @param query
     *            this is the collection of tokens to be added
     */
    private void add(Query query) {
        Set<String> keySet = query.keySet();

        for (String key : keySet) {
            List<String> list = query.getAll(key);
            String first = query.get(key);

            if (first != null) {
                this.all.put(key, list);
                this.map.put(key, first);
            }
        }
    }
}