JavaPlatformStringLookup.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.text.lookup;
import java.util.Locale;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.text.StringSubstitutor;
/**
* Looks up keys related to Java: Java version, JRE version, VM version, and so on.
* <p>
* The lookup keys with examples are:
* </p>
* <ul>
* <li><b>version</b>: "Java version 1.8.0_181"</li>
* <li><b>runtime</b>: "Java(TM) SE Runtime Environment (build 1.8.0_181-b13) from Oracle Corporation"</li>
* <li><b>vm</b>: "Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)"</li>
* <li><b>os</b>: "Windows 10 10.0, architecture: amd64-64"</li>
* <li><b>hardware</b>: "processors: 4, architecture: amd64-64, instruction sets: amd64"</li>
* <li><b>locale</b>: "default locale: en_US, platform encoding: iso-8859-1"</li>
* </ul>
*
* <p>
* Using a {@link StringLookup} from the {@link StringLookupFactory}:
* </p>
*
* <pre>
* StringLookupFactory.INSTANCE.javaPlatformStringLookup().lookup("version");
* </pre>
* <p>
* Using a {@link StringSubstitutor}:
* </p>
*
* <pre>
* StringSubstitutor.createInterpolator().replace("... ${java:version} ..."));
* </pre>
* <p>
* The above examples convert {@code "version"} to the current VM version, for example,
* {@code "Java version 1.8.0_181"}.
* </p>
*
* @since 1.3
*/
final class JavaPlatformStringLookup extends AbstractStringLookup {
/**
* Defines the singleton for this class.
*/
static final JavaPlatformStringLookup INSTANCE = new JavaPlatformStringLookup();
/** {@code hardware} key for driving {@link JavaPlatformStringLookup#lookup(String)}. */
private static final String KEY_HARDWARE = "hardware";
/** {@code locale} key for driving {@link JavaPlatformStringLookup#lookup(String)}. */
private static final String KEY_LOCALE = "locale";
/** {@code os} key for driving {@link JavaPlatformStringLookup#lookup(String)}. */
private static final String KEY_OS = "os";
/** {@code runtime} key for driving {@link JavaPlatformStringLookup#lookup(String)}. */
private static final String KEY_RUNTIME = "runtime";
/** {@code version} key for driving {@link JavaPlatformStringLookup#lookup(String)}. */
private static final String KEY_VERSION = "version";
/** {@code vm} key for driving {@link JavaPlatformStringLookup#lookup(String)}. */
private static final String KEY_VM = "vm";
/**
* The main method for running the JavaPlatformStringLookup.
*
* @param args the standard Java main method parameter which is unused for our running of this class.
*/
public static void main(final String[] args) {
System.out.println(JavaPlatformStringLookup.class);
System.out.printf("%s = %s%n", KEY_VERSION, JavaPlatformStringLookup.INSTANCE.lookup(KEY_VERSION));
System.out.printf("%s = %s%n", KEY_RUNTIME, JavaPlatformStringLookup.INSTANCE.lookup(KEY_RUNTIME));
System.out.printf("%s = %s%n", KEY_VM, JavaPlatformStringLookup.INSTANCE.lookup(KEY_VM));
System.out.printf("%s = %s%n", KEY_OS, JavaPlatformStringLookup.INSTANCE.lookup(KEY_OS));
System.out.printf("%s = %s%n", KEY_HARDWARE, JavaPlatformStringLookup.INSTANCE.lookup(KEY_HARDWARE));
System.out.printf("%s = %s%n", KEY_LOCALE, JavaPlatformStringLookup.INSTANCE.lookup(KEY_LOCALE));
}
/**
* No need to build instances for now.
*/
private JavaPlatformStringLookup() {
// empty
}
/**
* Accessible through the Lookup key {@code hardware}.
*
* @return hardware processor information.
*/
String getHardware() {
return "processors: " + Runtime.getRuntime().availableProcessors() + ", architecture: "
+ getSystemProperty("os.arch") + this.getSystemProperty("-", "sun.arch.data.model")
+ this.getSystemProperty(", instruction sets: ", "sun.cpu.isalist");
}
/**
* Accessible through the Lookup key {@code locale}.
*
* @return system locale and file encoding information.
*/
String getLocale() {
return "default locale: " + Locale.getDefault() + ", platform encoding: " + getSystemProperty("file.encoding");
}
/**
* Accessible through the Lookup key {@code os}.
*
* @return operating system information.
*/
String getOperatingSystem() {
return getSystemProperty("os.name") + " " + getSystemProperty("os.version")
+ getSystemProperty(" ", "sun.os.patch.level") + ", architecture: " + getSystemProperty("os.arch")
+ getSystemProperty("-", "sun.arch.data.model");
}
/**
* Accessible through the Lookup key {@code runtime}.
*
* @return Java Runtime Environment information.
*/
String getRuntime() {
return getSystemProperty("java.runtime.name") + " (build " + getSystemProperty("java.runtime.version")
+ ") from " + getSystemProperty("java.vendor");
}
/**
* Gets the given system property.
*
* @param name a system property name.
* @return a system property value.
*/
private String getSystemProperty(final String name) {
return StringLookupFactory.INSTANCE_SYSTEM_PROPERTIES.lookup(name);
}
/**
* Gets the given system property.
*
* @param prefix the prefix to use for the result string
* @param name a system property name.
* @return The prefix + a system property value.
*/
private String getSystemProperty(final String prefix, final String name) {
final String value = getSystemProperty(name);
if (StringUtils.isEmpty(value)) {
return StringUtils.EMPTY;
}
return prefix + value;
}
/**
* Accessible through the Lookup key {@code vm}.
*
* @return Java Virtual Machine information.
*/
String getVirtualMachine() {
return getSystemProperty("java.vm.name") + " (build " + getSystemProperty("java.vm.version") + ", "
+ getSystemProperty("java.vm.info") + ")";
}
/**
* Looks up the value of the Java platform key.
* <p>
* The lookup keys with examples are:
* </p>
* <ul>
* <li><b>version</b>: "Java version 1.8.0_181"</li>
* <li><b>runtime</b>: "Java(TM) SE Runtime Environment (build 1.8.0_181-b13) from Oracle Corporation"</li>
* <li><b>vm</b>: "Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)"</li>
* <li><b>os</b>: "Windows 10 10.0, architecture: amd64-64"</li>
* <li><b>hardware</b>: "processors: 4, architecture: amd64-64, instruction sets: amd64"</li>
* <li><b>locale</b>: "default locale: en_US, platform encoding: iso-8859-1"</li>
* </ul>
*
* @param key the key to be looked up, may be null
* @return The value of the environment variable.
*/
@Override
public String lookup(final String key) {
if (key == null) {
return null;
}
switch (key) {
case KEY_VERSION:
return "Java version " + getSystemProperty("java.version");
case KEY_RUNTIME:
return getRuntime();
case KEY_VM:
return getVirtualMachine();
case KEY_OS:
return getOperatingSystem();
case KEY_HARDWARE:
return getHardware();
case KEY_LOCALE:
return getLocale();
default:
throw new IllegalArgumentException(key);
}
}
}