org.springframework.boot.system.ApplicationTemp Maven / Gradle / Ivy
/*
* Copyright 2012-2018 the original author or 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
*
* https://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.springframework.boot.system;
import java.io.File;
import java.security.MessageDigest;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
/**
* Provides access to an application specific temporary directory. Generally speaking
* different Spring Boot applications will get different locations, however, simply
* restarting an application will give the same location.
*
* @author Phillip Webb
* @since 2.0.0
*/
public class ApplicationTemp {
private static final char[] HEX_CHARS = "0123456789ABCDEF".toCharArray();
private final Class sourceClass;
private volatile File dir;
/**
* Create a new {@link ApplicationTemp} instance.
*/
public ApplicationTemp() {
this(null);
}
/**
* Create a new {@link ApplicationTemp} instance for the specified source class.
* @param sourceClass the source class or {@code null}
*/
public ApplicationTemp(Class sourceClass) {
this.sourceClass = sourceClass;
}
@Override
public String toString() {
return getDir().getAbsolutePath();
}
/**
* Return a sub-directory of the application temp.
* @param subDir the sub-directory name
* @return a sub-directory
*/
public File getDir(String subDir) {
File dir = new File(getDir(), subDir);
dir.mkdirs();
return dir;
}
/**
* Return the directory to be used for application specific temp files.
* @return the application temp directory
*/
public File getDir() {
if (this.dir == null) {
synchronized (this) {
byte[] hash = generateHash(this.sourceClass);
this.dir = new File(getTempDirectory(), toHexString(hash));
this.dir.mkdirs();
Assert.state(this.dir.exists(),
() -> "Unable to create temp directory " + this.dir);
}
}
return this.dir;
}
private File getTempDirectory() {
String property = System.getProperty("java.io.tmpdir");
Assert.state(StringUtils.hasLength(property), "No 'java.io.tmpdir' property set");
File file = new File(property);
Assert.state(file.exists(), () -> "Temp directory " + file + " does not exist");
Assert.state(file.isDirectory(),
() -> "Temp location " + file + " is not a directory");
return file;
}
private byte[] generateHash(Class sourceClass) {
ApplicationHome home = new ApplicationHome(sourceClass);
MessageDigest digest;
try {
digest = MessageDigest.getInstance("SHA-1");
update(digest, home.getSource());
update(digest, home.getDir());
update(digest, System.getProperty("user.dir"));
update(digest, System.getProperty("java.home"));
update(digest, System.getProperty("java.class.path"));
update(digest, System.getProperty("sun.java.command"));
update(digest, System.getProperty("sun.boot.class.path"));
return digest.digest();
}
catch (Exception ex) {
throw new IllegalStateException(ex);
}
}
private void update(MessageDigest digest, Object source) {
if (source != null) {
digest.update(getUpdateSourceBytes(source));
}
}
private byte[] getUpdateSourceBytes(Object source) {
if (source instanceof File) {
return getUpdateSourceBytes(((File) source).getAbsolutePath());
}
return source.toString().getBytes();
}
private String toHexString(byte[] bytes) {
char[] hex = new char[bytes.length * 2];
for (int i = 0; i < bytes.length; i++) {
int b = bytes[i] & 0xFF;
hex[i * 2] = HEX_CHARS[b >>> 4];
hex[i * 2 + 1] = HEX_CHARS[b & 0x0F];
}
return new String(hex);
}
}