com.fitbur.bytebuddy.dynamic.loading.ClassLoadingStrategy Maven / Gradle / Ivy
package com.fitbur.bytebuddy.dynamic.loading;
import com.fitbur.bytebuddy.description.type.TypeDescription;
import java.io.File;
import java.lang.instrument.Instrumentation;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.ProtectionDomain;
import java.util.Map;
/**
* A strategy for loading a collection of types.
*/
public interface ClassLoadingStrategy {
/**
* Loads a given collection of classes given their binary representation.
*
* @param classLoader The class loader to used for loading the classes.
* @param types Byte array representations of the types to be loaded mapped by their descriptions,
* where an iteration order defines an order in which they are supposed to be loaded,
* if relevant.
* @return A collection of the loaded classes which will be initialized in the iteration order of the
* returned collection.
*/
Map> load(ClassLoader classLoader, Map types);
/**
* This class contains implementations of default class loading strategies.
*/
enum Default implements Configurable {
/**
* This strategy creates a new {@link com.fitbur.bytebuddy.dynamic.loading.ByteArrayClassLoader} with the given
* class loader as its parent. The byte array class loader is aware of a any dynamically created type and can
* natively load the given classes. This allows to load classes with cyclic load-time dependencies since the
* byte array class loader is queried on each encountered unknown class. Due to the encapsulation of the
* classes that were loaded by a byte array class loader, this strategy will lead to the unloading of these
* classes once this class loader, its classes or any instances of these classes become unreachable.
*/
WRAPPER(new WrappingDispatcher(ByteArrayClassLoader.PersistenceHandler.LATENT, WrappingDispatcher.PARENT_FIRST)),
/**
* The strategy is identical to {@link ClassLoadingStrategy.Default#WRAPPER} but exposes
* the byte arrays that represent a class by {@link java.lang.ClassLoader#getResourceAsStream(String)}. For
* this purpose, all class files are persisted as byte arrays withing the wrapping class loader.
*/
WRAPPER_PERSISTENT(new WrappingDispatcher(ByteArrayClassLoader.PersistenceHandler.MANIFEST, WrappingDispatcher.PARENT_FIRST)),
/**
*
* The child-first class loading strategy is a modified version of the
* {@link ClassLoadingStrategy.Default#WRAPPER} where the dynamic types are given
* priority over any types of a parent class loader with the same name.
*
*
* Important: This does not replace a type of the same name, but it makes the type invisible by
* the reach of this class loader.
*
*/
CHILD_FIRST(new WrappingDispatcher(ByteArrayClassLoader.PersistenceHandler.LATENT, WrappingDispatcher.CHILD_FIRST)),
/**
* The strategy is identical to {@link ClassLoadingStrategy.Default#CHILD_FIRST} but
* exposes the byte arrays that represent a class by {@link java.lang.ClassLoader#getResourceAsStream(String)}.
* For this purpose, all class files are persisted as byte arrays withing the wrapping class loader.
*/
CHILD_FIRST_PERSISTENT(new WrappingDispatcher(ByteArrayClassLoader.PersistenceHandler.MANIFEST, WrappingDispatcher.CHILD_FIRST)),
/**
*
* This strategy does not create a new class loader but injects all classes into the given {@link java.lang.ClassLoader}
* by reflective access. This prevents the loading of classes with cyclic load-time dependencies but avoids the
* creation of an additional class loader. The advantage of this strategy is that the loaded classes will have
* package-private access to other classes within their package of the class loader into which they are
* injected what is not permitted when the wrapper class loader is used. This strategy is implemented using a
* {@link com.fitbur.bytebuddy.dynamic.loading.ClassInjector.UsingReflection}. Note that this strategy usually yields
* a better runtime performance.
*
*
* Important: This class loader does not define packages for injected classes by default. Therefore, calls to
* {@link Class#getPackage()} might return {@code null}. Packages are only defined
*
*/
INJECTION(new InjectionDispatcher());
/**
* A convenience reference that references the default protection domain which is {@code null}.
*/
private static final ProtectionDomain DEFAULT_PROTECTION_DOMAIN = null;
/**
* The default behavior when attempting to load a type that was already loaded.
*/
private static final boolean DEFAULT_FORBID_EXISTING = true;
/**
* The dispatcher to be used when loading a class.
*/
private final Configurable dispatcher;
/**
* Creates a new default class loading strategy.
*
* @param dispatcher The dispatcher to be used when loading a class.
*/
Default(Configurable dispatcher) {
this.dispatcher = dispatcher;
}
@Override
public Map> load(ClassLoader classLoader, Map types) {
return dispatcher.load(classLoader, types);
}
@Override
public Configurable withProtectionDomain(ProtectionDomain protectionDomain) {
return dispatcher.withProtectionDomain(protectionDomain);
}
@Override
public Configurable withPackageDefinitionStrategy(PackageDefinitionStrategy packageDefinitionStrategy) {
return dispatcher.withPackageDefinitionStrategy(packageDefinitionStrategy);
}
@Override
public Configurable withAccessControlContext(AccessControlContext accessControlContext) {
return dispatcher.withAccessControlContext(accessControlContext);
}
@Override
public Configurable allowExistingTypes() {
return dispatcher.allowExistingTypes();
}
@Override
public String toString() {
return "ClassLoadingStrategy.Default." + name();
}
/**
* A class loading strategy which applies a class loader injection while applying a given
* {@link java.security.ProtectionDomain} on class injection.
*/
protected static class InjectionDispatcher implements ClassLoadingStrategy.Configurable {
/**
* The protection domain to apply.
*/
private final ProtectionDomain protectionDomain;
/**
* The access control context to use for loading classes.
*/
private final AccessControlContext accessControlContext;
/**
* The package definer to be used for querying information on package information.
*/
private final PackageDefinitionStrategy packageDefinitionStrategy;
/**
* Determines if an exception should be thrown when attempting to load a type that already exists.
*/
private final boolean forbidExisting;
/**
* Creates a new injection dispatcher.
*/
protected InjectionDispatcher() {
this(DEFAULT_PROTECTION_DOMAIN, AccessController.getContext(), PackageDefinitionStrategy.NoOp.INSTANCE, DEFAULT_FORBID_EXISTING);
}
/**
* Creates a new injection dispatcher.
*
* @param protectionDomain The protection domain to apply.
* @param accessControlContext The access control context to use for loading classes.
* @param packageDefinitionStrategy The package definer to be used for querying information on package information.
* @param forbidExisting Determines if an exception should be thrown when attempting to load a type that already exists.
*/
private InjectionDispatcher(ProtectionDomain protectionDomain,
AccessControlContext accessControlContext,
PackageDefinitionStrategy packageDefinitionStrategy,
boolean forbidExisting) {
this.protectionDomain = protectionDomain;
this.accessControlContext = accessControlContext;
this.packageDefinitionStrategy = packageDefinitionStrategy;
this.forbidExisting = forbidExisting;
}
@Override
public Map> load(ClassLoader classLoader, Map types) {
return new ClassInjector.UsingReflection(classLoader,
protectionDomain,
accessControlContext,
packageDefinitionStrategy,
forbidExisting).inject(types);
}
@Override
public Configurable withProtectionDomain(ProtectionDomain protectionDomain) {
return new InjectionDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, forbidExisting);
}
@Override
public Configurable withPackageDefinitionStrategy(PackageDefinitionStrategy packageDefinitionStrategy) {
return new InjectionDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, forbidExisting);
}
@Override
public Configurable withAccessControlContext(AccessControlContext accessControlContext) {
return new InjectionDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, forbidExisting);
}
@Override
public Configurable allowExistingTypes() {
return new InjectionDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, false);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
InjectionDispatcher that = (InjectionDispatcher) other;
return !(protectionDomain != null ? !protectionDomain.equals(that.protectionDomain) : that.protectionDomain != null)
&& accessControlContext.equals(that.accessControlContext)
&& forbidExisting == that.forbidExisting
&& packageDefinitionStrategy.equals(that.packageDefinitionStrategy);
}
@Override
public int hashCode() {
int result = protectionDomain != null ? protectionDomain.hashCode() : 0;
result = 31 * result + packageDefinitionStrategy.hashCode();
result = 31 * result + accessControlContext.hashCode();
result = 31 * result + (forbidExisting ? 1 : 0);
return result;
}
@Override
public String toString() {
return "ClassLoadingStrategy.Default.InjectionDispatcher{" +
"protectionDomain=" + protectionDomain +
", accessControlContext=" + accessControlContext +
", packageDefinitionStrategy=" + packageDefinitionStrategy +
", forbidExisting=" + forbidExisting +
'}';
}
}
/**
* A class loading strategy which creates a wrapping class loader while applying a given
* {@link java.security.ProtectionDomain} on class loading.
*/
protected static class WrappingDispatcher implements ClassLoadingStrategy.Configurable {
/**
* Indicates that a child first loading strategy should be attempted.
*/
private static final boolean CHILD_FIRST = true;
/**
* Indicates that a parent first loading strategy should be attempted.
*/
private static final boolean PARENT_FIRST = false;
/**
* The protection domain to apply.
*/
private final ProtectionDomain protectionDomain;
/**
* The access control context to use for loading classes.
*/
private final AccessControlContext accessControlContext;
/**
* The persistence handler to apply.
*/
private final ByteArrayClassLoader.PersistenceHandler persistenceHandler;
/**
* The package definer to be used for querying information on package information.
*/
private final PackageDefinitionStrategy packageDefinitionStrategy;
/**
* {@code true} if the created class loader should apply child-first semantics.
*/
private final boolean childFirst;
/**
* Determines if an exception should be thrown when attempting to load a type that already exists.
*/
private final boolean forbidExisting;
/**
* Creates a new wrapping dispatcher with a default protection domain and a default access control context.
*
* @param persistenceHandler The persistence handler to apply.
* @param childFirst {@code true} if the created class loader should apply child-first semantics.
*/
protected WrappingDispatcher(ByteArrayClassLoader.PersistenceHandler persistenceHandler, boolean childFirst) {
this(DEFAULT_PROTECTION_DOMAIN,
AccessController.getContext(),
PackageDefinitionStrategy.Trivial.INSTANCE,
persistenceHandler,
childFirst,
DEFAULT_FORBID_EXISTING);
}
/**
* Creates a new protection domain specific class loading wrapper.
*
* @param protectionDomain The protection domain to apply.
* @param accessControlContext The access control context to use for loading classes.
* @param packageDefinitionStrategy The package definer to be used for querying information on package information.
* @param persistenceHandler The persistence handler to apply.
* @param childFirst {@code true} if the created class loader should apply child-first semantics.
* @param forbidExisting Determines if an exception should be thrown when attempting to load a type that already exists.
*/
private WrappingDispatcher(ProtectionDomain protectionDomain,
AccessControlContext accessControlContext,
PackageDefinitionStrategy packageDefinitionStrategy,
ByteArrayClassLoader.PersistenceHandler persistenceHandler,
boolean childFirst,
boolean forbidExisting) {
this.protectionDomain = protectionDomain;
this.accessControlContext = accessControlContext;
this.packageDefinitionStrategy = packageDefinitionStrategy;
this.persistenceHandler = persistenceHandler;
this.childFirst = childFirst;
this.forbidExisting = forbidExisting;
}
@Override
public Map> load(ClassLoader classLoader, Map types) {
return ByteArrayClassLoader.load(classLoader,
types,
protectionDomain,
accessControlContext,
persistenceHandler,
packageDefinitionStrategy,
childFirst,
forbidExisting);
}
@Override
public Configurable withProtectionDomain(ProtectionDomain protectionDomain) {
return new WrappingDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, persistenceHandler, childFirst, forbidExisting);
}
@Override
public Configurable withPackageDefinitionStrategy(PackageDefinitionStrategy packageDefinitionStrategy) {
return new WrappingDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, persistenceHandler, childFirst, forbidExisting);
}
@Override
public Configurable withAccessControlContext(AccessControlContext accessControlContext) {
return new WrappingDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, persistenceHandler, childFirst, forbidExisting);
}
@Override
public Configurable allowExistingTypes() {
return new InjectionDispatcher(protectionDomain, accessControlContext, packageDefinitionStrategy, false);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
WrappingDispatcher that = (WrappingDispatcher) other;
return childFirst == that.childFirst
&& forbidExisting == that.forbidExisting
&& !(protectionDomain != null ? !protectionDomain.equals(that.protectionDomain) : that.protectionDomain != null)
&& persistenceHandler == that.persistenceHandler
&& accessControlContext.equals(that.accessControlContext)
&& packageDefinitionStrategy.equals(that.packageDefinitionStrategy);
}
@Override
public int hashCode() {
int result = protectionDomain != null ? protectionDomain.hashCode() : 0;
result = 31 * result + accessControlContext.hashCode();
result = 31 * result + persistenceHandler.hashCode();
result = 31 * result + packageDefinitionStrategy.hashCode();
result = 31 * result + (childFirst ? 1 : 0);
result = 31 * result + (forbidExisting ? 1 : 0);
return result;
}
@Override
public String toString() {
return "ClassLoadingStrategy.Default.WrappingDispatcher{" +
"packageDefinitionStrategy=" + packageDefinitionStrategy +
", protectionDomain=" + protectionDomain +
", accessControlContext=" + accessControlContext +
", childFirst=" + childFirst +
", persistenceHandler=" + persistenceHandler +
", forbidExisting=" + forbidExisting +
'}';
}
}
}
/**
* A {@link ClassLoadingStrategy} that allows configuring the strategy's behavior.
*/
interface Configurable extends ClassLoadingStrategy {
/**
* Overrides the implicitly set default {@link java.security.ProtectionDomain} with an explicit one.
*
* @param protectionDomain The protection domain to apply.
* @return This class loading strategy with an explicitly set {@link java.security.ProtectionDomain}.
*/
Configurable withProtectionDomain(ProtectionDomain protectionDomain);
/**
* Defines the supplied package definition strategy to be used for defining packages.
*
* @param packageDefinitionStrategy The package definer to be used.
* @return A version of this class loading strategy that applies the supplied package definition strategy.
*/
Configurable withPackageDefinitionStrategy(PackageDefinitionStrategy packageDefinitionStrategy);
/**
* Defines the supplied access control context to be used for loading classes.
*
* @param accessControlContext The access control context to use for loading classes.
* @return A version of this class loading strategy that applies the supplied access control context.
*/
Configurable withAccessControlContext(AccessControlContext accessControlContext);
/**
* Determines if this class loading strategy should not throw an exception when attempting to load a class that
* was already loaded. In this case, the already loaded class is used instead of the generated class.
*
* @return A version of this class loading strategy that does not throw an exception when a class is already loaded.
*/
Configurable allowExistingTypes();
}
/**
* A class loading strategy which allows class injection into the bootstrap class loader if
* appropriate.
*/
class ForBootstrapInjection implements ClassLoadingStrategy {
/**
* The instrumentation to use.
*/
private final Instrumentation instrumentation;
/**
* The folder to save jar files in.
*/
private final File folder;
/**
* Creates a new injector which is capable of injecting classes into the bootstrap class loader.
*
* @param instrumentation The instrumentation to use.
* @param folder The folder to save jar files in.
*/
public ForBootstrapInjection(Instrumentation instrumentation, File folder) {
this.instrumentation = instrumentation;
this.folder = folder;
}
@Override
public Map> load(ClassLoader classLoader, Map types) {
ClassInjector classInjector = classLoader == null
? ClassInjector.UsingInstrumentation.of(folder, ClassInjector.UsingInstrumentation.Target.BOOTSTRAP, instrumentation)
: new ClassInjector.UsingReflection(classLoader);
return classInjector.inject(types);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
ForBootstrapInjection that = (ForBootstrapInjection) other;
return folder.equals(that.folder)
&& instrumentation.equals(that.instrumentation);
}
@Override
public int hashCode() {
int result = instrumentation.hashCode();
result = 31 * result + folder.hashCode();
return result;
}
@Override
public String toString() {
return "ClassLoadingStrategy.ForBootstrapInjection{" +
"instrumentation=" + instrumentation +
", folder=" + folder +
'}';
}
}
}