184 lines
5.5 KiB
Java
184 lines
5.5 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.util.internal;
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import io.netty.util.internal.logging.InternalLogger;
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import io.netty.util.internal.logging.InternalLoggerFactory;
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import java.security.AccessController;
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import java.security.PrivilegedAction;
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/**
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* A collection of utility methods to retrieve and parse the values of the Java system properties.
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*/
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public final class SystemPropertyUtil {
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private static final InternalLogger logger = InternalLoggerFactory.getInstance(SystemPropertyUtil.class);
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/**
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* Returns {@code true} if and only if the system property with the specified {@code key}
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* exists.
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*/
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public static boolean contains(String key) {
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return get(key) != null;
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}
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/**
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* Returns the value of the Java system property with the specified
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* {@code key}, while falling back to {@code null} if the property access fails.
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*
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* @return the property value or {@code null}
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*/
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public static String get(String key) {
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return get(key, null);
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}
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/**
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* Returns the value of the Java system property with the specified
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* {@code key}, while falling back to the specified default value if
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* the property access fails.
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*
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* @return the property value.
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* {@code def} if there's no such property or if an access to the
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* specified property is not allowed.
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*/
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public static String get(final String key, String def) {
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if (key == null) {
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throw new NullPointerException("key");
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}
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if (key.isEmpty()) {
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throw new IllegalArgumentException("key must not be empty.");
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}
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String value = null;
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try {
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if (System.getSecurityManager() == null) {
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value = System.getProperty(key);
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} else {
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value = AccessController.doPrivileged((PrivilegedAction<String>) () -> System.getProperty(key));
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}
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} catch (SecurityException e) {
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logger.warn("Unable to retrieve a system property '{}'; default values will be used.", key, e);
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}
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if (value == null) {
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return def;
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}
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return value;
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}
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/**
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* Returns the value of the Java system property with the specified
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* {@code key}, while falling back to the specified default value if
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* the property access fails.
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*
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* @return the property value.
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* {@code def} if there's no such property or if an access to the
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* specified property is not allowed.
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*/
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public static boolean getBoolean(String key, boolean def) {
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String value = get(key);
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if (value == null) {
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return def;
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}
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value = value.trim().toLowerCase();
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if (value.isEmpty()) {
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return def;
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}
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if ("true".equals(value) || "yes".equals(value) || "1".equals(value)) {
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return true;
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}
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if ("false".equals(value) || "no".equals(value) || "0".equals(value)) {
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return false;
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}
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logger.warn(
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"Unable to parse the boolean system property '{}':{} - using the default value: {}",
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key, value, def
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);
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return def;
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}
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/**
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* Returns the value of the Java system property with the specified
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* {@code key}, while falling back to the specified default value if
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* the property access fails.
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*
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* @return the property value.
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* {@code def} if there's no such property or if an access to the
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* specified property is not allowed.
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*/
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public static int getInt(String key, int def) {
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String value = get(key);
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if (value == null) {
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return def;
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}
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value = value.trim();
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try {
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return Integer.parseInt(value);
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} catch (Exception e) {
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// Ignore
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}
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logger.warn(
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"Unable to parse the integer system property '{}':{} - using the default value: {}",
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key, value, def
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);
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return def;
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}
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/**
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* Returns the value of the Java system property with the specified
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* {@code key}, while falling back to the specified default value if
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* the property access fails.
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*
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* @return the property value.
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* {@code def} if there's no such property or if an access to the
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* specified property is not allowed.
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*/
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public static long getLong(String key, long def) {
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String value = get(key);
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if (value == null) {
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return def;
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}
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value = value.trim();
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try {
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return Long.parseLong(value);
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} catch (Exception e) {
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// Ignore
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}
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logger.warn(
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"Unable to parse the long integer system property '{}':{} - using the default value: {}",
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key, value, def
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);
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return def;
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}
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private SystemPropertyUtil() {
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// Unused
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}
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}
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