com.liferay.portal.util.JavaFieldsParser.java Source code

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Here is the source code for com.liferay.portal.util.JavaFieldsParser.java

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/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 */

package com.liferay.portal.util;

import com.liferay.portal.kernel.log.Log;
import com.liferay.portal.kernel.log.LogFactoryUtil;
import com.liferay.portal.kernel.util.StringUtil;

import java.lang.reflect.Field;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Brian Wing Shun Chan
 */
public class JavaFieldsParser {

    public static String parse(ClassLoader classLoader, String s) {
        int x = s.indexOf("${");

        if (x == -1) {
            return s;
        }

        List<String> replaceFrom = new ArrayList<>();
        List<String> replaceWith = new ArrayList<>();

        while (true) {
            if (x == -1) {
                break;
            }

            int y = s.indexOf("}", x);

            if (y == -1) {
                break;
            }

            String javaSnippet = s.substring(x + 2, y);

            if (_log.isDebugEnabled()) {
                _log.debug("Java snippet " + javaSnippet);
            }

            String className = _getClassName(javaSnippet);

            if (_log.isDebugEnabled()) {
                _log.debug("Class name " + className);
            }

            if (className == null) {
                break;
            }

            Class<?> clazz = null;

            try {
                clazz = classLoader.loadClass(className);
            } catch (Exception e) {
                _log.error("Unable to load class " + className, e);

                break;
            }

            String fieldName = _getFieldName(javaSnippet);

            if (_log.isDebugEnabled()) {
                _log.debug("Field name " + fieldName);
            }

            if (fieldName == null) {
                break;
            }

            String fieldValue = null;

            try {
                Field field = clazz.getField(fieldName);

                fieldValue = String.valueOf(field.get(null));

                if (_log.isDebugEnabled()) {
                    _log.debug("Field value " + fieldValue);
                }
            } catch (Exception e) {
                _log.error("Unable to load field " + fieldName, e);

                break;
            }

            replaceFrom.add("${".concat(javaSnippet).concat("}"));
            replaceWith.add(fieldValue);

            x = s.indexOf("${", y);
        }

        if (replaceFrom.isEmpty()) {
            return s;
        }

        return StringUtil.replace(s, replaceFrom.toArray(new String[0]), replaceWith.toArray(new String[0]));
    }

    private static String _getClassName(String javaSnippet) {
        int x = javaSnippet.lastIndexOf(".");

        if (x == -1) {
            return null;
        }

        return javaSnippet.substring(0, x);
    }

    private static String _getFieldName(String javaSnippet) {
        int x = javaSnippet.lastIndexOf(".");

        if (x == -1) {
            return null;
        }

        return javaSnippet.substring(x + 1);
    }

    private static final Log _log = LogFactoryUtil.getLog(JavaFieldsParser.class);

}