StubAgentJar.java
/*-
* #%L
* io.earcam.instrumental.agent
* %%
* Copyright (C) 2018 earcam
* %%
* SPDX-License-Identifier: (BSD-3-Clause OR EPL-1.0 OR Apache-2.0 OR MIT)
*
* You <b>must</b> choose to accept, in full - any individual or combination of
* the following licenses:
* <ul>
* <li><a href="https://opensource.org/licenses/BSD-3-Clause">BSD-3-Clause</a></li>
* <li><a href="https://www.eclipse.org/legal/epl-v10.html">EPL-1.0</a></li>
* <li><a href="https://www.apache.org/licenses/LICENSE-2.0">Apache-2.0</a></li>
* <li><a href="https://opensource.org/licenses/MIT">MIT</a></li>
* </ul>
* #L%
*/
package io.earcam.instrumental.agent;
import static io.earcam.instrumental.archive.AsAgentJar.asAgentJar;
import static io.earcam.instrumental.archive.Archive.archive;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.UUID;
import io.earcam.instrumental.reflect.Resources;
import io.earcam.unexceptional.Exceptional;
final class StubAgentJar {
static final String JAR_PREFIX = "stub-agent-";
static final String JAR_EXTENSION = ".jar";
private StubAgentJar()
{}
static Path jarForAgentClass(Class<?> agentClass)
{
Path sourceOfResource = sourceOfResource(agentClass);
if(!sourceOfResource.toFile().isFile()) {
Path stubJar = Exceptional.apply(StubAgentJar::stubAgentJar, agentClass);
Runtime.getRuntime().addShutdownHook(new Thread(() -> StubAgentJar.removeStubAgentJar(stubJar)));
sourceOfResource = stubJar;
}
return sourceOfResource;
}
private static Path sourceOfResource(Class<?> agentClass)
{
return Exceptional.apply(Path::toRealPath, Paths.get(Resources.sourceOfResource(agentClass)));
}
private static void removeStubAgentJar(Path sourceOfResource)
{
Exceptional.accept(Files::delete, sourceOfResource);
}
private static Path stubAgentJar(Class<?> agentClass)
{
return stubAgentJar(JAR_PREFIX, agentClass);
}
static Path stubAgentJar(String jarPrefix, Class<?> agentClass)
{
Path jar = Exceptional.apply(File::createTempFile, jarPrefix + UUID.randomUUID(), JAR_EXTENSION).toPath();
return archive()
.configured(
asAgentJar()
.withAgentClass(agentClass)
.canRedefineClasses()
.canRetransformClasses())
.to(jar);
}
}