com.linkedin.urls.detection.CharUtils.java Source code

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Here is the source code for com.linkedin.urls.detection.CharUtils.java

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/**
 * Copyright 2015 LinkedIn Corp. All rights reserved.
 * 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 athttp://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.
 *
 */
package com.linkedin.urls.detection;

import java.util.ArrayList;
import org.apache.commons.lang3.StringUtils;

public class CharUtils {

    /**
     * Checks if character is a valid hex character.
     */
    public static boolean isHex(char a) {
        return (a >= '0' && a <= '9') || (a >= 'a' && a <= 'f') || (a >= 'A' && a <= 'F');
    }

    /**
     * Checks if character is a valid alphabetic character.
     */
    public static boolean isAlpha(char a) {
        return ((a >= 'a' && a <= 'z') || (a >= 'A' && a <= 'Z'));
    }

    /**
     * Checks if character is a valid numeric character.
     */
    public static boolean isNumeric(char a) {
        return a >= '0' && a <= '9';
    }

    /**
     * Checks if character is a valid alphanumeric character.
     */
    public static boolean isAlphaNumeric(char a) {
        return isAlpha(a) || isNumeric(a);
    }

    /**
     * Checks if character is a valid unreserved character. This is defined by the RFC 3986 ABNF
     */
    public static boolean isUnreserved(char a) {
        return isAlphaNumeric(a) || a == '-' || a == '.' || a == '_' || a == '~';
    }

    /**
     * Checks if character is a dot. Heres the doc:
     * http://docs.oracle.com/javase/6/docs/api/java/net/IDN.html#toASCII%28java.lang.String,%20int%29
     */
    public static boolean isDot(char a) {
        return (a == '.' || a == '\u3002' || a == '\uFF0E' || a == '\uFF61');
    }

    public static boolean isWhiteSpace(char a) {
        return (a == '\n' || a == '\t' || a == '\r' || a == ' ');
    }

    /**
     * Splits a string without the use of a regex, which could split either by isDot() or %2e
     * @param input the input string that will be split by dot
     * @return an array of strings that is a partition of the original string split by dot
     */
    public static String[] splitByDot(String input) {
        ArrayList<String> splitList = new ArrayList<String>();
        StringBuilder section = new StringBuilder();
        if (StringUtils.isEmpty(input)) {
            return new String[] { "" };
        }
        InputTextReader reader = new InputTextReader(input);
        while (!reader.eof()) {
            char curr = reader.read();
            if (isDot(curr)) {
                splitList.add(section.toString());
                section.setLength(0);
            } else if (curr == '%' && reader.canReadChars(2) && reader.peek(2).equalsIgnoreCase("2e")) {
                reader.read();
                reader.read(); //advance past the 2e
                splitList.add(section.toString());
                section.setLength(0);
            } else {
                section.append(curr);
            }
        }
        splitList.add(section.toString());
        return splitList.toArray(new String[splitList.size()]);
    }

    private CharUtils() {
    }
}