Commons FileUpload example source code file (ParameterParser.java)

This example Commons FileUpload source code file (ParameterParser.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons FileUpload tags/keywords

hashmap, hashmap, map, map, parameterparser, parameterparser, string, string, util

The Commons FileUpload ParameterParser.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.commons.fileupload;

import java.util.HashMap;
import java.util.Map;

/**
 * A simple parser intended to parse sequences of name/value pairs.
 * Parameter values are exptected to be enclosed in quotes if they
 * contain unsafe characters, such as '=' characters or separators.
 * Parameter values are optional and can be omitted.
 *
 * <p>
 *  <code>param1 = value; param2 = "anything goes; really"; param3
 * </p>
 *
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski
 */

public class ParameterParser {
    /**
     * String to be parsed.
     */
    private char[] chars = null;

    /**
     * Current position in the string.
     */
    private int pos = 0;

    /**
     * Maximum position in the string.
     */
    private int len = 0;

    /**
     * Start of a token.
     */
    private int i1 = 0;

    /**
     * End of a token.
     */
    private int i2 = 0;

    /**
     * Whether names stored in the map should be converted to lower case.
     */
    private boolean lowerCaseNames = false;

    /**
     * Default ParameterParser constructor.
     */
    public ParameterParser() {
        super();
    }

    /**
     * Are there any characters left to parse?
     *
     * @return <tt>true if there are unparsed characters,
     *         <tt>false otherwise.
     */
    private boolean hasChar() {
        return this.pos < this.len;
    }

    /**
     * A helper method to process the parsed token. This method removes
     * leading and trailing blanks as well as enclosing quotation marks,
     * when necessary.
     *
     * @param quoted <tt>true if quotation marks are expected,
     *               <tt>false otherwise.
     * @return the token
     */
    private String getToken(boolean quoted) {
        // Trim leading white spaces
        while ((i1 < i2) && (Character.isWhitespace(chars[i1]))) {
            i1++;
        }
        // Trim trailing white spaces
        while ((i2 > i1) && (Character.isWhitespace(chars[i2 - 1]))) {
            i2--;
        }
        // Strip away quotation marks if necessary
        if (quoted) {
            if (((i2 - i1) >= 2)
                && (chars[i1] == '"')
                && (chars[i2 - 1] == '"')) {
                i1++;
                i2--;
            }
        }
        String result = null;
        if (i2 > i1) {
            result = new String(chars, i1, i2 - i1);
        }
        return result;
    }

    /**
     * Tests if the given character is present in the array of characters.
     *
     * @param ch the character to test for presense in the array of characters
     * @param charray the array of characters to test against
     *
     * @return <tt>true if the character is present in the array of
     *   characters, <tt>false otherwise.
     */
    private boolean isOneOf(char ch, final char[] charray) {
        boolean result = false;
        for (int i = 0; i < charray.length; i++) {
            if (ch == charray[i]) {
                result = true;
                break;
            }
        }
        return result;
    }

    /**
     * Parses out a token until any of the given terminators
     * is encountered.
     *
     * @param terminators the array of terminating characters. Any of these
     * characters when encountered signify the end of the token
     *
     * @return the token
     */
    private String parseToken(final char[] terminators) {
        char ch;
        i1 = pos;
        i2 = pos;
        while (hasChar()) {
            ch = chars[pos];
            if (isOneOf(ch, terminators)) {
                break;
            }
            i2++;
            pos++;
        }
        return getToken(false);
    }

    /**
     * Parses out a token until any of the given terminators
     * is encountered outside the quotation marks.
     *
     * @param terminators the array of terminating characters. Any of these
     * characters when encountered outside the quotation marks signify the end
     * of the token
     *
     * @return the token
     */
    private String parseQuotedToken(final char[] terminators) {
        char ch;
        i1 = pos;
        i2 = pos;
        boolean quoted = false;
        boolean charEscaped = false;
        while (hasChar()) {
            ch = chars[pos];
            if (!quoted && isOneOf(ch, terminators)) {
                break;
            }
            if (!charEscaped && ch == '"') {
                quoted = !quoted;
            }
            charEscaped = (!charEscaped && ch == '\\');
            i2++;
            pos++;

        }
        return getToken(true);
    }

    /**
     * Returns <tt>true if parameter names are to be converted to lower
     * case when name/value pairs are parsed.
     *
     * @return <tt>true if parameter names are to be
     * converted to lower case when name/value pairs are parsed.
     * Otherwise returns <tt>false
     */
    public boolean isLowerCaseNames() {
        return this.lowerCaseNames;
    }

    /**
     * Sets the flag if parameter names are to be converted to lower case when
     * name/value pairs are parsed.
     *
     * @param b <tt>true if parameter names are to be
     * converted to lower case when name/value pairs are parsed.
     * <tt>false otherwise.
     */
    public void setLowerCaseNames(boolean b) {
        this.lowerCaseNames = b;
    }

    /**
     * Extracts a map of name/value pairs from the given string. Names are
     * expected to be unique.
     *
     * @param str the string that contains a sequence of name/value pairs
     * @param separator the name/value pairs separator
     *
     * @return a map of name/value pairs
     */
    public Map parse(final String str, char separator) {
        if (str == null) {
            return new HashMap();
        }
        return parse(str.toCharArray(), separator);
    }

    /**
     * Extracts a map of name/value pairs from the given array of
     * characters. Names are expected to be unique.
     *
     * @param chars the array of characters that contains a sequence of
     * name/value pairs
     * @param separator the name/value pairs separator
     *
     * @return a map of name/value pairs
     */
    public Map parse(final char[] chars, char separator) {
        if (chars == null) {
            return new HashMap();
        }
        return parse(chars, 0, chars.length, separator);
    }

    /**
     * Extracts a map of name/value pairs from the given array of
     * characters. Names are expected to be unique.
     *
     * @param chars the array of characters that contains a sequence of
     * name/value pairs
     * @param offset - the initial offset.
     * @param length - the length.
     * @param separator the name/value pairs separator
     *
     * @return a map of name/value pairs
     */
    public Map parse(
        final char[] chars,
        int offset,
        int length,
        char separator) {

        if (chars == null) {
            return new HashMap();
        }
        HashMap params = new HashMap();
        this.chars = chars;
        this.pos = offset;
        this.len = length;

        String paramName = null;
        String paramValue = null;
        while (hasChar()) {
            paramName = parseToken(new char[] {
                    '=', separator });
            paramValue = null;
            if (hasChar() && (chars[pos] == '=')) {
                pos++; // skip '='
                paramValue = parseQuotedToken(new char[] {
                        separator });
            }
            if (hasChar() && (chars[pos] == separator)) {
                pos++; // skip separator
            }
            if ((paramName != null) && (paramName.length() > 0)) {
                if (this.lowerCaseNames) {
                    paramName = paramName.toLowerCase();
                }
                params.put(paramName, paramValue);
            }
        }
        return params;
    }
}