Java Regex String Replace replace(Pattern pattern, String src, Function<String, String> handler)

Description

Replace string with pattern obtaining replacement values through handler function.

License

Apache License

Parameter

Parameter	Description
pattern	pattern
src	source string
handler	function which take matched part of source string and return replacement value, must never return null

Return

result string

Declaration

public static String replace(Pattern pattern, String src, Function<String, String> handler)

Method Source Code

//package com.java2s;
/*/*from  w  w  w. j  a  va2 s.  c  o  m*/
 * Copyright 2016 Code Above Lab LLC
 *
 * 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.
 */

import java.util.function.Function;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    /**
     * Replace string with pattern obtaining replacement values through handler function. <p/>
     * Note that it differ from usual Pattern behavior when it process replacement for group references,
     * this code do nothing with replacement.
     * @param pattern pattern
     * @param src source string
     * @param handler function which take matched part of source string and return replacement value, must never return null
     * @return result string
     */
    public static String replace(Pattern pattern, String src, Function<String, String> handler) {
        StringBuilder sb = null;
        Matcher matcher = pattern.matcher(src);
        int pos = 0;
        while (matcher.find()) {
            if (sb == null) {
                // replacement can be a very rare operation, and we not need excess string buffer
                sb = new StringBuilder();
            }
            String expr = matcher.group();
            String replacement = handler.apply(expr);
            sb.append(src, pos, matcher.start());
            sb.append(replacement);
            pos = matcher.end();
        }
        if (sb == null) {
            return src;
        }
        sb.append(src, pos, src.length());
        return sb.toString();
    }
}

Java Regex String Replace replace(Pattern pattern, String src, Function handler)

Description

License

Parameter

Return

Declaration

Method Source Code

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