tokenfilter.java

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        /**
         * Filter a string 'line' replacing from with to
         * (C&P from the Replace task)
         * @param line the string to be filtered
         * @return the filtered line
         */
        public String filter(String line) {
            if (from == null) {
                throw new BuildException("Missing from in stringreplace");
            }
            StringBuffer ret = new StringBuffer();
            int start = 0;
            int found = line.indexOf(from);
            while (found >= 0) {
                // write everything up to the from
                if (found > start) {
                    ret.append(line.substring(start, found));
                }

                // write the replacement to
                if (to != null) {
                    ret.append(to);
                }

                // search again
                start = found + from.length();
                found = line.indexOf(from, start);
            }

            // write the remaining characters
            if (line.length() > start) {
                ret.append(line.substring(start, line.length()));
            }

            return ret.toString();
        }
    }

    /**
     * Simple filter to filter lines contains strings
     */
    public static class ContainsString extends ProjectComponent
        implements Filter {
        private String contains;

        /**
         * the contains attribute
         * @param contains the string that the token should contain
         */
        public void setContains(String contains) {
            this.contains = contains;
        }

        /**
         * Filter strings that contain the contains attribute
         *
         * @param string the string to be filtered
         * @return null if the string does not contain "contains",
         *              string otherwise
         */
        public String filter(String string) {
            if (contains == null) {
                throw new BuildException("Missing contains in containsstring");
            }
            if (string.indexOf(contains) > -1) {
                return string;
            }
            return null;
        }
    }

    /**
     * filter to replace regex.
     */
    public static class ReplaceRegex extends ChainableReaderFilter {
        private String             from;
        private String             to;
        private RegularExpression  regularExpression;
        private Substitution       substitution;
        private boolean            initialized = false;
        private String             flags = "";
        private int                options;
        private Regexp             regexp;

        /**
         * the from attribute
         * @param from the regex string
         */
        public void setPattern(String from) {
            this.from = from;
        }
        /**
         * the to attribute
         * @param to the replacement string
         */
        public void setReplace(String to) {
            this.to = to;
        }

        /**
         * @param flags the regex flags
         */
        public void setFlags(String flags) {
            this.flags = flags;
        }

        private void initialize() {
            if (initialized) {
                return;
            }
            options = convertRegexOptions(flags);
            if (from == null) {
                throw new BuildException("Missing pattern in replaceregex");
            }
            regularExpression = new RegularExpression();
            regularExpression.setPattern(from);
            regexp = regularExpression.getRegexp(getProject());
            if (to == null) {
                to = "";
            }
            substitution = new Substitution();
            substitution.setExpression(to);
        }

        /**
         * @param line the string to modify
         * @return the modified string
         */
        public String filter(String line) {
            initialize();

            if (!regexp.matches(line, options)) {
                return line;
            }
            return regexp.substitute(
                line, substitution.getExpression(getProject()), options);
        }
    }

    /**
     * filter to filter tokens matching regular expressions.
     */
    public static class ContainsRegex extends ChainableReaderFilter {
        private String             from;
        private String             to;
        private RegularExpression  regularExpression;
        private Substitution       substitution;
        private boolean            initialized = false;
        private String             flags = "";
        private int                options;
        private Regexp             regexp;


        /**
         * @param from the regex pattern
         */
        public void setPattern(String from) {
            this.from = from;
        }

        /**
         * @param to the replacement string
         */
        public void setReplace(String to) {
            this.to = to;
        }

        /**
         * @param flags the regex flags
         */
        public void setFlags(String flags) {
            this.flags = flags;
        }

        private void initialize() {
            if (initialized) {
                return;
            }
            options = convertRegexOptions(flags);
            if (from == null) {
                throw new BuildException("Missing from in containsregex");
            }
            regularExpression = new RegularExpression();
            regularExpression.setPattern(from);
            regexp = regularExpression.getRegexp(getProject());
            if (to == null) {
                return;
            }
            substitution = new Substitution();
            substitution.setExpression(to);
        }

        /**
         * apply regex and substitution on a string
         * @param string the string to apply filter on
         * @return the filtered string
         */
        public String filter(String string) {
            initialize();
            if (!regexp.matches(string, options)) {
                return null;
            }
            if (substitution == null) {
                return string;
            }
            return regexp.substitute(
                string, substitution.getExpression(getProject()), options);
        }
    }

    /** Filter to trim white space */
    public static class Trim extends ChainableReaderFilter {
        /**
         * @param line the string to be trimmed
         * @return the trimmed string
         */
        public String filter(String line) {
            return line.trim();
        }
    }



    /** Filter remove empty tokens */
    public static class IgnoreBlank extends ChainableReaderFilter {
        /**
         * @param line the line to modify
         * @return the trimmed line
         */
        public String filter(String line) {
            if (line.trim().length() == 0) {
                return null;
            }
            return line;
        }
    }

    /**
     * Filter to delete characters
     */
    public static class DeleteCharacters extends ProjectComponent
        implements Filter, ChainableReader {
        // Attributes
        /** the list of characters to remove from the input */
        private String deleteChars = "";

        /**
         * Set the list of characters to delete
         * @param deleteChars the list of characters
         */
        public void setChars(String deleteChars) {
            this.deleteChars = resolveBackSlash(deleteChars);
        }

        /**
         * remove characters from a string
         * @param string the string to remove the characters from
         * @return the converted string
         */
        public String filter(String string) {
            StringBuffer output = new StringBuffer(string.length());
            for (int i = 0; i < string.length(); ++i) {
                char ch = string.charAt(i);
                if (!(isDeleteCharacter(ch))) {
                    output.append(ch);
                }
            }
            return output.toString();
        }

        /**
         * factory method to provide a reader that removes
         * the characters from a reader as part of a filter
         * chain
         * @param reader the reader object
         * @return the chained reader object
         */
        public Reader chain(Reader reader) {
            return new BaseFilterReader(reader) {
                /**
                 * @return the next non delete character
                 */
                public int read()
                    throws IOException {
                    while (true) {
                        int c = in.read();
                        if (c == -1) {
                            return c;
                        }
                        if (!(isDeleteCharacter((char) c))) {
                            return c;
                        }
                    }
                }
            };
        }

        /**
         *  check if the character c is to be deleted
         *
         * @param c char to test
         * @return true if the supplied char is in the list to be stripped.
         */
        private boolean isDeleteCharacter(char c) {
            for (int d = 0; d < deleteChars.length(); ++d) {
                if (deleteChars.charAt(d) ==  c) {
                    return true;
                }
            }
            return false;
        }
    }

    // --------------------------------------------------------
    //  static utility methods - could be placed somewhere else
    // --------------------------------------------------------

    /**
     * xml does not do "c" like interpretation of strings.
     * i.e. \n\r\t etc.
     * this method processes \n, \r, \t, \f, \\
     * also subs \s -> " \n\r\t\f"
     * a trailing '\' will be ignored
     *
     * @param input raw string with possible embedded '\'s
     * @return converted string
     */
    public static String resolveBackSlash(String input) {
        return StringUtils.resolveBackSlash(input);
    }

    /**
     * convert regex option flag characters to regex options
     * <dl>
     *   <li>g -  Regexp.REPLACE_ALL</li>
     *   <li>i -  Regexp.MATCH_CASE_INSENSITIVE</li>
     *   <li>m -  Regexp.MATCH_MULTILINE</li>
     *   <li>s -  Regexp.MATCH_SINGLELINE</li>
     * </dl>
     * @param flags the string containing the flags
     * @return the Regexp option bits
     */
    public static int convertRegexOptions(String flags) {
        if (flags == null) {
            return 0;
        }
        int options = 0;
        if (flags.indexOf('g') != -1) {
            options |= Regexp.REPLACE_ALL;
        }
        if (flags.indexOf('i') != -1) {
            options |= Regexp.MATCH_CASE_INSENSITIVE;
        }
        if (flags.indexOf('m') != -1) {
            options |= Regexp.MATCH_MULTILINE;
        }
        if (flags.indexOf('s') != -1) {
            options |= Regexp.MATCH_SINGLELINE;
        }
        return options;
    }
}