Java tutorial
/* * Copyright (C) 2012 The Guava Authors * * 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.google.common.base; import com.google.common.annotations.Beta; import com.google.common.annotations.GwtIncompatible; import javax.annotation.CheckReturnValue; import javax.annotation.Nullable; /** * Represents a {@linkplain System#getProperties() standard system property}. * * @author Kurt Alfred Kluever * @since 15.0 */ @Beta @GwtIncompatible("java.lang.System#getProperty") @CheckReturnValue public enum StandardSystemProperty { /** Java Runtime Environment version. */ JAVA_VERSION("java.version"), /** Java Runtime Environment vendor. */ JAVA_VENDOR("java.vendor"), /** Java vendor URL. */ JAVA_VENDOR_URL("java.vendor.url"), /** Java installation directory. */ JAVA_HOME("java.home"), /** Java Virtual Machine specification version. */ JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"), /** Java Virtual Machine specification vendor. */ JAVA_VM_SPECIFICATION_VENDOR("java.vm.specification.vendor"), /** Java Virtual Machine specification name. */ JAVA_VM_SPECIFICATION_NAME("java.vm.specification.name"), /** Java Virtual Machine implementation version. */ JAVA_VM_VERSION("java.vm.version"), /** Java Virtual Machine implementation vendor. */ JAVA_VM_VENDOR("java.vm.vendor"), /** Java Virtual Machine implementation name. */ JAVA_VM_NAME("java.vm.name"), /** Java Runtime Environment specification version. */ JAVA_SPECIFICATION_VERSION("java.specification.version"), /** Java Runtime Environment specification vendor. */ JAVA_SPECIFICATION_VENDOR("java.specification.vendor"), /** Java Runtime Environment specification name. */ JAVA_SPECIFICATION_NAME("java.specification.name"), /** Java class format version number. */ JAVA_CLASS_VERSION("java.class.version"), /** Java class path. */ JAVA_CLASS_PATH("java.class.path"), /** List of paths to search when loading libraries. */ JAVA_LIBRARY_PATH("java.library.path"), /** Default temp file path. */ JAVA_IO_TMPDIR("java.io.tmpdir"), /** Name of JIT compiler to use. */ JAVA_COMPILER("java.compiler"), /** Path of extension directory or directories. */ JAVA_EXT_DIRS("java.ext.dirs"), /** Operating system name. */ OS_NAME("os.name"), /** Operating system architecture. */ OS_ARCH("os.arch"), /** Operating system version. */ OS_VERSION("os.version"), /** File separator ("/" on UNIX). */ FILE_SEPARATOR("file.separator"), /** Path separator (":" on UNIX). */ PATH_SEPARATOR("path.separator"), /** Line separator ("\n" on UNIX). */ LINE_SEPARATOR("line.separator"), /** User's account name. */ USER_NAME("user.name"), /** User's home directory. */ USER_HOME("user.home"), /** User's current working directory. */ USER_DIR("user.dir"); private final String key; private StandardSystemProperty(String key) { this.key = key; } /** * Returns the key used to lookup this system property. */ public String key() { return key; } /** * Returns the current value for this system property by delegating to * {@link System#getProperty(String)}. */ @Nullable public String value() { return System.getProperty(key); } /** * Returns a string representation of this system property. */ @Override public String toString() { return key() + "=" + value(); } }