groovy.util.ProxyGenerator Maven / Gradle / Ivy
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/*
* 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 groovy.util;
import groovy.lang.Closure;
import groovy.lang.DelegatingMetaClass;
import groovy.lang.GroovyObject;
import groovy.lang.GroovySystem;
import groovy.lang.MetaClass;
import org.codehaus.groovy.runtime.InvokerHelper;
import org.codehaus.groovy.runtime.MetaClassHelper;
import org.codehaus.groovy.runtime.ProxyGeneratorAdapter;
import org.codehaus.groovy.runtime.memoize.LRUCache;
import org.codehaus.groovy.runtime.typehandling.GroovyCastException;
import org.codehaus.groovy.transform.trait.Traits;
import java.lang.ref.WeakReference;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
/**
* Classes to generate 'Proxy' objects which implement interfaces,
* maps of closures and/or extend classes/delegates.
*/
public class ProxyGenerator {
private static final Class[] EMPTY_INTERFACE_ARRAY = MetaClassHelper.EMPTY_TYPE_ARRAY;
private static final Map EMPTY_CLOSURE_MAP = Collections.emptyMap();
private static final Set EMPTY_KEYSET = Collections.emptySet();
static {
// wrap the standard MetaClass with the delegate
setMetaClass(GroovySystem.getMetaClassRegistry().getMetaClass(ProxyGenerator.class));
}
private ClassLoader override = null;
private boolean debug = false;
private boolean emptyMethods = false;
private static final Integer GROOVY_ADAPTER_CACHE_DEFAULT_SIZE = Integer.getInteger("groovy.adapter.cache.default.size", 64);
public static final ProxyGenerator INSTANCE = new ProxyGenerator(); // TODO should we make ProxyGenerator singleton?
/**
* The adapter cache is used to cache proxy classes. When, for example, a call like:
* map as MyClass is found, then a lookup is made into the cache to find if a suitable
* adapter already exists. If so, then the class is reused, instead of generating a
* new class.
*/
private final LRUCache adapterCache = new LRUCache(GROOVY_ADAPTER_CACHE_DEFAULT_SIZE);
public boolean getDebug() {
return debug;
}
/**
* Instructs ProxyGenerator to dump generated Groovy
* source code to standard output during construction. This is useful
* for debugging purposes but should be turned off in production.
*
* @param debug true if you want generated source to be printed
*/
public void setDebug(boolean debug) {
this.debug = debug;
}
public boolean getEmptyMethods() {
return emptyMethods;
}
/**
* Changes generated methods to have empty implementations.
*
* Methods in generated aggregates not supplied in a closures map or
* base class are given 'default' implementations. The implementation
* will normally throw an UnsupportedOperationException
* but setting this boolean will leave it empty.
*
* @param emptyMethods true if you want generated methods to be empty
*/
public void setEmptyMethods(boolean emptyMethods) {
this.emptyMethods = emptyMethods;
}
public ClassLoader getOverride() {
return override;
}
public void setOverride(ClassLoader override) {
this.override = override;
}
public GroovyObject instantiateAggregateFromBaseClass(Class clazz) {
return instantiateAggregateFromBaseClass((Map) null, clazz);
}
public GroovyObject instantiateAggregateFromBaseClass(Map map, Class clazz) {
return instantiateAggregateFromBaseClass(map, clazz, null);
}
public GroovyObject instantiateAggregateFromBaseClass(Closure cl, Class clazz) {
Map m = new HashMap();
m.put("*", cl);
return instantiateAggregateFromBaseClass(m, clazz, null);
}
public GroovyObject instantiateAggregateFromBaseClass(Class clazz, Object[] constructorArgs) {
return instantiateAggregate(null, null, clazz, constructorArgs);
}
public GroovyObject instantiateAggregateFromBaseClass(Map map, Class clazz, Object[] constructorArgs) {
return instantiateAggregate(map, null, clazz, constructorArgs);
}
public GroovyObject instantiateAggregateFromInterface(Class clazz) {
return instantiateAggregateFromInterface(null, clazz);
}
public GroovyObject instantiateAggregateFromInterface(Map map, Class clazz) {
List interfaces = new ArrayList();
interfaces.add(clazz);
return instantiateAggregate(map, interfaces);
}
public GroovyObject instantiateAggregate(List interfaces) {
return instantiateAggregate(null, interfaces);
}
public GroovyObject instantiateAggregate(Map closureMap, List interfaces) {
return instantiateAggregate(closureMap, interfaces, null);
}
public GroovyObject instantiateAggregate(Map closureMap, List interfaces, Class clazz) {
return instantiateAggregate(closureMap, interfaces, clazz, null);
}
@SuppressWarnings("unchecked")
public GroovyObject instantiateAggregate(Map closureMap, List interfaces, Class clazz, Object[] constructorArgs) {
if (clazz != null && Modifier.isFinal(clazz.getModifiers())) {
throw new GroovyCastException("Cannot coerce a map to class " + clazz.getName() + " because it is a final class");
}
Map map = closureMap != null ? closureMap : EMPTY_CLOSURE_MAP;
ProxyGeneratorAdapter adapter = createAdapter(map, interfaces, null, clazz);
return adapter.proxy(map, constructorArgs);
}
public GroovyObject instantiateDelegate(Object delegate) {
return instantiateDelegate(null, delegate);
}
public GroovyObject instantiateDelegate(List interfaces, Object delegate) {
return instantiateDelegate(null, interfaces, delegate);
}
public GroovyObject instantiateDelegate(Map closureMap, List interfaces, Object delegate) {
return instantiateDelegateWithBaseClass(closureMap, interfaces, delegate, null);
}
public GroovyObject instantiateDelegateWithBaseClass(Map closureMap, List interfaces, Object delegate) {
return instantiateDelegateWithBaseClass(closureMap, interfaces, delegate, delegate.getClass());
}
public GroovyObject instantiateDelegateWithBaseClass(Map closureMap, List interfaces, Object delegate, Class baseClass) {
return instantiateDelegateWithBaseClass(closureMap, interfaces, delegate, baseClass, null);
}
/**
* Creates a proxy with a delegate object.
*
* @param closureMap the closure for methods not handled by the delegate
* @param interfaces interfaces to be implemented
* @param delegate the delegate object
* @param baseClass the base class
* @param name the name of the proxy, unused, but kept for compatibility with previous versions of Groovy.
* @return a proxy object implementing the specified interfaces, and delegating to the provided object
*/
@SuppressWarnings("unchecked")
public GroovyObject instantiateDelegateWithBaseClass(Map closureMap, List interfaces, Object delegate, Class baseClass, String name) {
Map map = closureMap != null ? closureMap : EMPTY_CLOSURE_MAP;
ProxyGeneratorAdapter adapter = createAdapter(map, interfaces, delegate.getClass(), baseClass);
return adapter.delegatingProxy(delegate, map, (Object[])null);
}
private ProxyGeneratorAdapter createAdapter(Map closureMap, List interfaces, Class delegateClass, Class baseClass) {
// According to https://shipilev.net/blog/2016/arrays-wisdom-ancients/#_conclusion
// toArray(new T[0]) seems faster, safer, and contractually cleaner, and therefore should be the default choice now.
Class[] intfs = interfaces != null ? interfaces.toArray(EMPTY_INTERFACE_ARRAY) : EMPTY_INTERFACE_ARRAY;
Class base = baseClass;
if (base == null) {
if (intfs.length > 0) {
base = intfs[0];
} else {
base = Object.class;
}
}
Set keys = closureMap == EMPTY_CLOSURE_MAP ? EMPTY_KEYSET : new HashSet();
for (Object o : closureMap.keySet()) {
keys.add(o.toString());
}
boolean useDelegate = null != delegateClass;
CacheKey key = new CacheKey(base, useDelegate ? delegateClass : Object.class, keys, intfs, emptyMethods, useDelegate);
final Class b = base;
return (ProxyGeneratorAdapter) adapterCache.getAndPut(
key,
k -> new ProxyGeneratorAdapter(closureMap, b, intfs, useDelegate
? delegateClass.getClassLoader()
: b.getClassLoader(), emptyMethods, useDelegate ? delegateClass : null
)
);
}
private static void setMetaClass(final MetaClass metaClass) {
final MetaClass newMetaClass = new DelegatingMetaClass(metaClass) {
@Override
public Object invokeStaticMethod(Object object, String methodName, Object[] arguments) {
return InvokerHelper.invokeMethod(INSTANCE, methodName, arguments);
}
};
GroovySystem.getMetaClassRegistry().setMetaClass(ProxyGenerator.class, newMetaClass);
}
private static final class CacheKey {
private static final Comparator INTERFACE_COMPARATOR = (o1, o2) -> {
// Traits order *must* be preserved
// See GROOVY-7285
if (Traits.isTrait(o1)) return -1;
if (Traits.isTrait(o2)) return 1;
return o1.getName().compareTo(o2.getName());
};
private final boolean emptyMethods;
private final boolean useDelegate;
private final Set methods;
private final ClassReference delegateClass;
private final ClassReference baseClass;
private final ClassReference[] interfaces;
private CacheKey(final Class baseClass, final Class delegateClass, final Set methods, final Class[] interfaces, final boolean emptyMethods, final boolean useDelegate) {
this.useDelegate = useDelegate;
this.baseClass = new ClassReference(baseClass);
this.delegateClass = new ClassReference(delegateClass);
this.emptyMethods = emptyMethods;
this.interfaces = interfaces == null ? null : new ClassReference[interfaces.length];
if (interfaces != null) {
Class[] interfacesCopy = new Class[interfaces.length];
System.arraycopy(interfaces, 0, interfacesCopy, 0, interfaces.length);
Arrays.sort(interfacesCopy, INTERFACE_COMPARATOR);
for (int i = 0; i < interfacesCopy.length; i++) {
Class anInterface = interfacesCopy[i];
this.interfaces[i] = new ClassReference(anInterface);
}
}
this.methods = methods;
}
@Override
public boolean equals(final Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
final CacheKey cacheKey = (CacheKey) o;
if (emptyMethods != cacheKey.emptyMethods) return false;
if (useDelegate != cacheKey.useDelegate) return false;
if (!Objects.equals(baseClass, cacheKey.baseClass)) return false;
if (!Objects.equals(delegateClass, cacheKey.delegateClass)) return false;
if (!Arrays.equals(interfaces, cacheKey.interfaces)) return false;
if (!Objects.equals(methods, cacheKey.methods)) return false;
return true;
}
@Override
public int hashCode() {
int result = (emptyMethods ? 1 : 0);
result = 31 * result + (useDelegate ? 1 : 0);
result = 31 * result + (methods != null ? methods.hashCode() : 0);
result = 31 * result + (baseClass != null ? baseClass.hashCode() : 0);
result = 31 * result + (delegateClass != null ? delegateClass.hashCode() : 0);
result = 31 * result + (interfaces != null ? Arrays.hashCode(interfaces) : 0);
return result;
}
/**
* A weak reference which delegates equals and hashcode to the referent.
*/
private static class ClassReference extends WeakReference {
public ClassReference(Class referent) {
super(referent);
}
@Override
public boolean equals(final Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Class thisClass = this.get();
ClassReference that = (ClassReference) o;
if (thisClass == null) return false;
return thisClass.equals(that.get());
}
@Override
public int hashCode() {
Class thisClass = this.get();
if (thisClass == null) return 0;
return thisClass.hashCode();
}
}
}
}