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Polaris Common Model JAR
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/*
 * Tencent is pleased to support the open source community by making Polaris available.
 *
 * Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the BSD 3-Clause License (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/BSD-3-Clause
 *
 * 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 com.tencent.polaris.api.utils;

import java.util.Objects;

public class StringUtils {

    public static boolean isBlank(String str) {
        int strLen;
        if (str != null && (strLen = str.length()) != 0) {
            for (int i = 0; i < strLen; ++i) {
                if (!Character.isWhitespace(str.charAt(i))) {
                    return false;
                }
            }
        }
        return true;
    }

    public static String defaultString(String value) {
        if (null == value) {
            return "";
        }
        return value;
    }

    public static boolean isNotBlank(String str) {
        return !isBlank(str);
    }

    public static boolean equals(String str1, String str2) {
        return Objects.equals(str1, str2);
    }

    public static boolean isEmpty(String str) {
        return str == null || str.length() == 0;
    }

    public static boolean isNotEmpty(String str) {
        return !isEmpty(str);
    }

    public static String replace(String text, String searchString, String replacement) {
        return replace(text, searchString, replacement, -1);
    }

    /**
     * 替换字符串
     *
     * @param text text
     * @param searchString searchString
     * @param replacement replacement
     * @param max max
     * @return 结果
     */
    public static String replace(String text, String searchString, String replacement, int max) {
        if (!isEmpty(text) && !isEmpty(searchString) && replacement != null && max != 0) {
            int start = 0;
            int end = text.indexOf(searchString, start);
            if (end == -1) {
                return text;
            } else {
                int replLength = searchString.length();
                int increase = replacement.length() - replLength;
                increase = increase < 0 ? 0 : increase;
                increase *= max < 0 ? 16 : (max > 64 ? 64 : max);

                StringBuilder buf = new StringBuilder(text.length() + increase);
                for (; end != -1; end = text.indexOf(searchString, start)) {
                    buf.append(text.substring(start, end)).append(replacement);
                    start = end + replLength;
                    --max;
                    if (max == 0) {
                        break;
                    }
                }

                buf.append(text.substring(start));
                return buf.toString();
            }
        } else {
            return text;
        }
    }

    /**
     * Test whether the given string matches the given substring
     * at the given index.
     *
     * @param str the original string (or StringBuilder)
     * @param index the index in the original string to start matching against
     * @param substring the substring to match at the given index
     */
    public static boolean substringMatch(CharSequence str, int index, CharSequence substring) {
        if (index + substring.length() > str.length()) {
            return false;
        }
        for (int i = 0; i < substring.length(); i++) {
            if (str.charAt(index + i) != substring.charAt(i)) {
                return false;
            }
        }
        return true;
    }
}