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/*
 * Copyright (c) 2008-2024 The Aspectran Project
 *
 * 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.
 */
package com.aspectran.utils;

import com.aspectran.utils.annotation.jsr305.Nullable;
import com.aspectran.utils.logging.Logger;
import com.aspectran.utils.logging.LoggerFactory;

/**
 * Helpers for java.lang.System.
 */
public abstract class SystemUtils {

    private static final Logger logger = LoggerFactory.getLogger(SystemUtils.class);

    private static final String JAVA_IO_TMPDIR_PROPERTY = "java.io.tmpdir";

    private static final String USER_HOME_PROPERTY = "user.home";

    private static final String USER_DIR_PROPERTY = "user.dir";

    /**
     * Gets a System property, defaulting to {@code null} if the property
     * cannot be read.
     * If a {@code SecurityException} is caught, the return value is {@code null}.
     * @param key the name of the system property
     * @return the system property value or {@code null} if a security problem occurs
     */
    @Nullable
    public static String getProperty(String key) {
        try {
            return System.getProperty(key);
        } catch (Exception ex) { // AccessControlException is deprecated for removal
            if (logger.isDebugEnabled()) {
                logger.debug(String.format(
                        "Caught AccessControlException when accessing system property [%s]; " +
                                "its value will be returned [null]. Reason: %s",
                        key, ex.getMessage()));
            }
            return null;
        }
    }

    public static String getProperty(String name, String defVal) {
        String val = getProperty(name);
        return (val != null ? val : defVal);
    }

    @Nullable
    public static String clearProperty(String key) {
        try {
            return System.clearProperty(key);
        } catch (Exception ex) { // AccessControlException is deprecated for removal
            if (logger.isDebugEnabled()) {
                logger.debug(String.format(
                    "Caught AccessControlException when accessing system property [%s]. Reason: %s",
                    key, ex.getMessage()));
            }
            return null;
        }
    }

    public static String getJavaIoTmpDir() {
        return getProperty(JAVA_IO_TMPDIR_PROPERTY);
    }

    public static String getUserHome() {
        return getProperty(USER_HOME_PROPERTY);
    }

    public static String getUserDir() {
        return getProperty(USER_DIR_PROPERTY);
    }

}