groovy.util.ProxyGenerator Maven / Gradle / Ivy
/*
* Copyright 2003-2013 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
*
* 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.*;
import org.codehaus.groovy.runtime.*;
import org.codehaus.groovy.runtime.memoize.LRUCache;
import java.lang.ref.WeakReference;
import java.util.*;
/**
* Classes to generate 'Proxy' objects which implement interfaces,
* maps of closures and/or extend classes/delegates.
*
* @author Paul King
* @author Guillaume Laforge
* @author Cedric Champeau
*/
public class ProxyGenerator {
private static final Class[] EMPTY_INTERFACE_ARRAY = new Class[0];
private static final Map EMPTY_CLOSURE_MAP = Collections.emptyMap();
private static final Set EMPTY_KEYSET = Collections.emptySet();
public static final ProxyGenerator INSTANCE = new ProxyGenerator();
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;
/**
* 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(16);
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) {
Map map = closureMap!=null?closureMap: EMPTY_CLOSURE_MAP;
Class[] intfs = interfaces!=null? interfaces.toArray(new Class[interfaces.size()]): EMPTY_INTERFACE_ARRAY;
Class base = clazz;
if (base==null) {
if (intfs.length>0) {
base=intfs[0];
} else {
base = Object.class;
}
}
Set keys = map==EMPTY_CLOSURE_MAP?EMPTY_KEYSET:new HashSet();
for (Object o : map.keySet()) {
keys.add(o.toString());
}
CacheKey key = new CacheKey(base, keys, intfs, emptyMethods, false);
ProxyGeneratorAdapter adapter = (ProxyGeneratorAdapter) adapterCache.get(key);
if (adapter==null) {
adapter = new ProxyGeneratorAdapter(map, base, intfs, base.getClassLoader(), emptyMethods, null);
adapterCache.put(key, adapter);
}
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;
Class[] intfs = interfaces!=null? interfaces.toArray(new Class[interfaces.size()]): EMPTY_INTERFACE_ARRAY;
Class base = baseClass;
if (base==null) {
if (intfs.length>0) {
base=intfs[0];
} else {
base = Object.class;
}
}
Set keys = map==EMPTY_CLOSURE_MAP?EMPTY_KEYSET:new HashSet();
for (Object o : map.keySet()) {
keys.add(o.toString());
}
CacheKey key = new CacheKey(base, keys, intfs, emptyMethods, true);
ProxyGeneratorAdapter adapter = (ProxyGeneratorAdapter) adapterCache.get(key);
if (adapter==null) {
adapter = new ProxyGeneratorAdapter(map, base, intfs, delegate.getClass().getClassLoader(), emptyMethods, delegate.getClass());
adapterCache.put(key, adapter);
}
return adapter.delegatingProxy(delegate, map, (Object[])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 class CacheKey {
private static final Comparator CLASSNAME_COMPARATOR = new Comparator() {
public int compare(final Class o1, final Class o2) {
return o1.getName().compareTo(o2.getName());
}
};
private final boolean emptyMethods;
private final boolean useDelegate;
private final Set methods;
private final ClassReference baseClass;
private final ClassReference[] interfaces;
private CacheKey(final Class baseClass, final Set methods, final Class[] interfaces, final boolean emptyMethods, final boolean useDelegate) {
this.useDelegate = useDelegate;
this.baseClass = new ClassReference(baseClass);
this.emptyMethods = emptyMethods;
this.interfaces = interfaces == null ? null : new ClassReference[interfaces.length];
if (interfaces != null) {
Arrays.sort(interfaces, CLASSNAME_COMPARATOR);
for (int i = 0; i < interfaces.length; i++) {
Class anInterface = interfaces[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 (baseClass != null ? !baseClass.equals(cacheKey.baseClass) : cacheKey.baseClass != null) return false;
if (!Arrays.equals(interfaces, cacheKey.interfaces)) return false;
if (methods != null ? !methods.equals(cacheKey.methods) : cacheKey.methods != null) 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 + (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();
}
}
}
}