com.tencent.process.Util Maven / Gradle / Ivy

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/*
 * The MIT License
 *
 * Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.tencent.process;

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

// copy from jenkins 96a66619b55b3b78b86817798fe36e58b2798cd4

public class Util {
    /**
     * Convert null to "".
     */
    public static String fixNull(String s) {
        return fixNull(s, "");
    }

    /**
     * Convert {@code null} to a default value.
     *
     * @param defaultValue Default value. It may be immutable or not, depending on the implementation.
     * @since 2.144
     */
    public static  T fixNull(T s, T defaultValue) {
        return s != null ? s : defaultValue;
    }

    /**
     * Pattern for capturing variables. Either $xyz, ${xyz} or ${a.b} but not $a.b, while ignoring "$$"
     */
    private static final Pattern VARIABLE = Pattern.compile("\\$([A-Za-z0-9_]+|\\{[A-Za-z0-9_.]+\\}|\\$)");

    /**
     * Replaces the occurrence of '$key' by {@code properties.get('key')}.
     *
     * 
     * Unlike shell, undefined variables are left as-is (this behavior is the same as Ant.)
     */
    public static String replaceMacro(String s, Map properties) {
        return replaceMacro(s, new VariableResolver.ByMap<>(properties));
    }

    /**
     * Replaces the occurrence of '$key' by {@code resolver.get('key')}.
     *
     * 
     * Unlike shell, undefined variables are left as-is (this behavior is the same as Ant.)
     */
    public static String replaceMacro(String s, VariableResolver resolver) {
        if (s == null) {
            return null;
        }

        int idx = 0;
        while (true) {
            Matcher m = VARIABLE.matcher(s);
            if (!m.find(idx)) return s;

            String key = m.group().substring(1);

            // escape the dollar sign or get the key to resolve
            String value;
            if (key.charAt(0) == '$') {
                value = "$";
            } else {
                if (key.charAt(0) == '{') key = key.substring(1, key.length() - 1);
                value = resolver.resolve(key);
            }

            if (value == null)
                idx = m.end(); // skip this
            else {
                s = s.substring(0, m.start()) + value + s.substring(m.end());
                idx = m.start() + value.length();
            }
        }
    }
}