net.sandius.rembulan.load.ChunkClassLoader Maven / Gradle / Ivy
/*
* Copyright 2016 Miroslav Janíček
*
* 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 net.sandius.rembulan.load;
import net.sandius.rembulan.util.ByteVector;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* Class loader for Lua chunks.
*/
public class ChunkClassLoader extends ClassLoader {
private final Map installed;
private final Set loaded;
/**
* Constructs a new {@code ChunkClassLoader} with the specified class loader {@code parent}
* as its parent in the class loading hierarchy.
*
* @param parent the parent class loader
*/
public ChunkClassLoader(ClassLoader parent) {
super(parent);
this.installed = new HashMap<>();
this.loaded = new HashSet<>();
}
/**
* Constructs a new {@code ChunkClassLoader} using the class loader that loaded
* the {@code ChunkClassLoader} class as the parent class loader.
*/
public ChunkClassLoader() {
this(ChunkClassLoader.class.getClassLoader());
}
/**
* Installs the compiled chunk {@code chunk} into this chunk class loader, returning
* the class name of the main class in {@code chunk}.
*
* Once this method returns (and not before), the returned main class may be loaded
* and instantiated.
*
* @param chunk chunk to be installed, must not be {@code null}
* @return the class name of the main class in {@code chunk}
*
* @throws NullPointerException if {@code chunk} is {@code null}
* @throws IllegalStateException if a class with the same name as a class in {@code chunk}
* has already been installed into this chunk class loader
*
*/
public String install(CompiledChunk chunk) {
Map classes = chunk.classMap();
synchronized (this) {
for (String name : classes.keySet()) {
if (installed.containsKey(name) || loaded.contains(name)) {
// class already installed
throw new IllegalStateException("Class already installed: " + name);
}
installed.put(name, classes.get(name));
}
String main = chunk.mainClassName();
assert (installed.containsKey(main));
return main;
}
}
/**
* Returns {@code true} if the Lua function class with the given {@code className}
* has been installed into this {@code ChunkClassLoader} or has already been loaded by it.
*
* @param className class name of the Lua function, must not be {@code null}
* @return {@code true} iff the class {@code className} has been installed into this
* class loader or loaded by it
* @throws NullPointerException if {@code className} is {@code null}
*/
public boolean isInstalled(String className) {
synchronized (this) {
return installed.containsKey(className) || loaded.contains(className);
}
}
@Override
protected Class findClass(String name) throws ClassNotFoundException {
synchronized (this) {
ByteVector bv = installed.remove(name);
if (bv != null) {
loaded.add(name);
return defineClass(name, bv);
}
else {
throw new ClassNotFoundException(name);
}
}
}
private Class defineClass(String name, ByteVector bytes) {
byte[] byteArray = bytes.copyToNewArray();
return defineClass(name, byteArray, 0, byteArray.length);
}
}