org.codehaus.groovy.runtime.metaclass.ClosureMetaClass Maven / Gradle / Ivy
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/*
* Copyright 2003-2007 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 org.codehaus.groovy.runtime.metaclass;
import groovy.lang.*;
import org.codehaus.groovy.reflection.CachedClass;
import org.codehaus.groovy.reflection.CachedField;
import org.codehaus.groovy.reflection.CachedMethod;
import org.codehaus.groovy.reflection.FastArray;
import org.codehaus.groovy.runtime.InvokerHelper;
import org.codehaus.groovy.runtime.MetaClassHelper;
import org.codehaus.groovy.runtime.wrappers.Wrapper;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.*;
import java.util.logging.Level;
/**
* A Metaclass for closures generated by the Groovy compiler. These classes
* have special characteristics this MetaClass uses. One of these is that a
* generated Closure has only additional doCall methods, all other methods
* are in the Closure class as well. To use this fact this MetaClass uses
* a MetaClass for Closure as static field And delegates calls to this
* MetaClass if needed. This allows a lean implementation for this MetaClass.
* Multiple generated closures will then use the same MetaClass for Closure.
* For static dispatching this class uses the MetaClass of Class, again
* all isntances of this class will share that MetaClass. The Class MetaClass
* is initialized lazy, because most operations do not need this MetaClass.
*
* The Closure and Class MetaClasses are not replaceable.
*
* This MetaClass is for internal usage only!
*
* @author Jochen Theodorou
* @since 1.1
*/
public final class ClosureMetaClass extends MetaClassImpl {
private boolean initialized;
private final FastArray closureMethods = new FastArray(3);
private Map attributes = new HashMap();
private MethodChooser chooser;
private volatile boolean attributeInitDone = false;
private static final MetaClassImpl CLOSURE_METACLASS;
private static MetaClassImpl classMetaClass;
private static final Object[] EMPTY_ARGUMENTS = {};
private static final String CLOSURE_CALL_METHOD = "call";
private static final String CLOSURE_DO_CALL_METHOD = "doCall";
private static final String CLOSURE_CURRY_METHOD = "curry";
static {
CLOSURE_METACLASS = new MetaClassImpl(Closure.class);
CLOSURE_METACLASS.initialize();
}
private static synchronized MetaClass getStaticMetaClass() {
if (classMetaClass == null) {
classMetaClass = new MetaClassImpl(Class.class);
classMetaClass.initialize();
}
return classMetaClass;
}
private static interface MethodChooser {
Object chooseMethod(Class[] arguments, boolean coerce);
}
private static class StandardClosureChooser implements MethodChooser {
private final MetaMethod doCall0;
private final MetaMethod doCall1;
StandardClosureChooser(MetaMethod m0, MetaMethod m1) {
doCall0 = m0;
doCall1 = m1;
}
public Object chooseMethod(Class[] arguments, boolean coerce) {
if (arguments.length == 0) return doCall0;
if (arguments.length == 1) return doCall1;
return null;
}
}
private static class NormalMethodChooser implements MethodChooser {
private final FastArray methods;
final Class theClass;
NormalMethodChooser(Class theClass, FastArray methods) {
this.theClass = theClass;
this.methods = methods;
}
public Object chooseMethod(Class[] arguments, boolean coerce) {
if (arguments.length == 0) {
return MetaClassHelper.chooseEmptyMethodParams(methods);
} else if (arguments.length == 1 && arguments[0] == null) {
return MetaClassHelper.chooseMostGeneralMethodWith1NullParam(methods);
} else {
List matchingMethods = new ArrayList();
final int len = methods.size();
final Object[] data = methods.getArray();
for (int i = 0; i != len; ++i) {
Object method = data[i];
// making this false helps find matches
if (MetaClassHelper.isValidMethod(method, arguments, coerce)) {
matchingMethods.add(method);
}
}
if (matchingMethods.isEmpty()) {
return null;
} else if (matchingMethods.size() == 1) {
return matchingMethods.get(0);
}
return chooseMostSpecificParams(CLOSURE_DO_CALL_METHOD, matchingMethods, arguments);
}
}
private Object chooseMostSpecificParams(String name, List matchingMethods, Class[] arguments) {
long matchesDistance = -1;
LinkedList matches = new LinkedList();
for (Iterator iter = matchingMethods.iterator(); iter.hasNext();) {
Object method = iter.next();
Class[] paramTypes = MetaClassHelper.getParameterTypes(method).getNativeParameterTypes();
if (!MetaClassHelper.parametersAreCompatible(arguments, paramTypes)) continue;
long dist = MetaClassHelper.calculateParameterDistance(arguments, paramTypes);
if (dist == 0) return method;
if (matches.isEmpty()) {
matches.add(method);
matchesDistance = dist;
} else if (dist < matchesDistance) {
matchesDistance = dist;
matches.clear();
matches.add(method);
} else if (dist == matchesDistance) {
matches.add(method);
}
}
if (matches.size() == 1) {
return matches.getFirst();
}
if (matches.isEmpty()) {
return null;
}
//more than one matching method found --> ambigous!
String msg = "Ambiguous method overloading for method ";
msg += theClass.getName() + "#" + name;
msg += ".\nCannot resolve which method to invoke for ";
msg += InvokerHelper.toString(arguments);
msg += " due to overlapping prototypes between:";
for (Iterator iter = matches.iterator(); iter.hasNext();) {
CachedClass[] types = MetaClassHelper.getParameterTypes(iter.next()).getParameterTypes();
msg += "\n\t" + InvokerHelper.toString(types);
}
throw new GroovyRuntimeException(msg);
}
}
public ClosureMetaClass(MetaClassRegistry registry, Class theClass) {
super(registry, theClass);
}
public MetaProperty getMetaProperty(String name) {
return CLOSURE_METACLASS.getMetaProperty(name);
}
private void unwrap(Object[] arguments) {
for (int i = 0; i != arguments.length; i++) {
if (arguments[i] instanceof Wrapper) {
arguments[i] = ((Wrapper) arguments[i]).unwrap();
}
}
}
private MetaMethod pickClosureMethod(Class[] argClasses) {
Object answer = chooser.chooseMethod(argClasses, false);
return (MetaMethod) answer;
}
private MetaMethod getDelegateMethod(Closure closure, Object delegate, String methodName, Class[] argClasses) {
if (delegate == closure || delegate == null) return null;
MetaClass delegateMetaClass = lookupObjectMetaClass(delegate);
return delegateMetaClass.pickMethod(methodName, argClasses);
}
public Object invokeMethod(Class sender, Object object, String methodName, Object[] originalArguments, boolean isCallToSuper, boolean fromInsideClass) {
checkInitalised();
if (object == null) {
throw new NullPointerException("Cannot invoke method: " + methodName + " on null object");
}
if (LOG.isLoggable(Level.FINER)) {
MetaClassHelper.logMethodCall(object, methodName, originalArguments);
}
final Object[] arguments = originalArguments == null ? EMPTY_ARGUMENTS : originalArguments;
final Class[] argClasses = MetaClassHelper.convertToTypeArray(arguments);
unwrap(arguments);
MetaMethod method;
final Closure closure = (Closure) object;
if (CLOSURE_DO_CALL_METHOD.equals(methodName) || CLOSURE_CALL_METHOD.equals(methodName)) {
method = pickClosureMethod(argClasses);
if (method==null && arguments.length==1 && arguments[0] instanceof List) {
Object[] newArguments = ((List) arguments[0]).toArray();
Class[] newArgClasses = MetaClassHelper.convertToTypeArray(newArguments);
method = pickClosureMethod(newArgClasses);
if (method!=null) {
method = new TransformMetaMethod(method) {
public Object invoke(Object object, Object[] arguments) {
Object firstArgument = arguments[0];
List list = (List) firstArgument;
arguments = list.toArray();
return super.invoke(object, arguments);
}
};
}
}
} else if (CLOSURE_CURRY_METHOD.equals(methodName)) {
return closure.curry(arguments);
} else {
method = CLOSURE_METACLASS.pickMethod(methodName, argClasses);
}
if (method != null) return MetaClassHelper.doMethodInvoke(object, method, arguments);
MissingMethodException last = null;
Object callObject = object;
if (method == null) {
final Object owner = closure.getOwner();
final Object delegate = closure.getDelegate();
final Object thisObject = closure.getThisObject();
final int resolveStrategy = closure.getResolveStrategy();
boolean invokeOnDelegate = false;
boolean invokeOnOwner = false;
boolean ownerFirst = true;
switch (resolveStrategy) {
case Closure.TO_SELF:
break;
case Closure.DELEGATE_ONLY:
method = getDelegateMethod(closure, delegate, methodName, argClasses);
callObject = delegate;
if (method == null) {
invokeOnDelegate = delegate != closure && (delegate instanceof GroovyObject);
}
break;
case Closure.OWNER_ONLY:
method = getDelegateMethod(closure, owner, methodName, argClasses);
callObject = owner;
if (method == null) {
invokeOnOwner = owner != closure && (owner instanceof GroovyObject);
}
break;
case Closure.DELEGATE_FIRST:
method = getDelegateMethod(closure, delegate, methodName, argClasses);
callObject = delegate;
if (method == null) {
method = getDelegateMethod(closure, owner, methodName, argClasses);
callObject = owner;
}
if (method == null) {
invokeOnDelegate = delegate != closure && (delegate instanceof GroovyObject);
invokeOnOwner = owner != closure && (owner instanceof GroovyObject);
ownerFirst = false;
}
break;
default: // owner first
// owner first means we start with the outer most owner that is not a generated closure
// this owner is equal to the this object, so we check that one first.
method = getDelegateMethod(closure, thisObject, methodName, argClasses);
callObject = thisObject;
if (method == null) {
//try finding a delegate that has that method... we start from
// outside building a stack and try each delegate
LinkedList list = new LinkedList();
for (Object current = closure; current!=thisObject; ) {
Closure currentClosure = (Closure) current;
if (currentClosure.getDelegate()!=null) list.add(current);
current=currentClosure.getOwner();
}
while (!list.isEmpty() && method==null) {
Closure closureWithDelegate = (Closure) list.removeLast();
Object currentDelegate = closureWithDelegate.getDelegate();
method = getDelegateMethod(closureWithDelegate,currentDelegate,methodName,argClasses);
callObject = currentDelegate;
}
}
if (method == null) {
invokeOnDelegate = delegate != closure && (delegate instanceof GroovyObject);
invokeOnOwner = owner != closure && (owner instanceof GroovyObject);
}
}
if (method == null && (invokeOnOwner || invokeOnDelegate)) {
try {
if (ownerFirst) {
return invokeOnDelegationObjects(invokeOnOwner, owner, invokeOnDelegate, delegate, methodName, arguments);
} else {
return invokeOnDelegationObjects(invokeOnDelegate, delegate, invokeOnOwner, owner, methodName, arguments);
}
} catch (MissingMethodException mme) {
last = mme;
}
}
}
if (method != null) {
return MetaClassHelper.doMethodInvoke(callObject, method, arguments);
} else {
// if no method was found, try to find a closure defined as a field of the class and run it
Object value = null;
try {
value = this.getProperty(object, methodName);
} catch (MissingPropertyException mpe) {
// ignore
}
if (value instanceof Closure) { // This test ensures that value != this If you ever change this ensure that value != this
Closure cl = (Closure) value;
MetaClass delegateMetaClass = cl.getMetaClass();
return delegateMetaClass.invokeMethod(cl.getClass(), closure, CLOSURE_DO_CALL_METHOD, originalArguments, false, fromInsideClass);
}
}
if (last != null) throw last;
throw new MissingMethodException(methodName, theClass, arguments, false);
}
private Object invokeOnDelegationObjects(
boolean invoke1, Object o1,
boolean invoke2, Object o2,
String methodName, Object[] args) {
MissingMethodException first = null;
if (invoke1) {
GroovyObject go = (GroovyObject) o1;
try {
return go.invokeMethod(methodName, args);
} catch (MissingMethodException mme) {
first = mme;
}
}
if (invoke2) {
GroovyObject go = (GroovyObject) o2;
try {
return go.invokeMethod(methodName, args);
} catch (MissingMethodException mme) {
if (first == null) first = mme;
}
}
throw first;
}
private synchronized void initAttributes() {
if (!attributes.isEmpty()) return;
attributes.put("!", null); // just a dummy for later
CachedField[] fieldArray = theCachedClass.getFields();
for (int i = 0; i < fieldArray.length; i++) {
MetaFieldProperty mfp = MetaFieldProperty.create(fieldArray[i]);
attributes.put(fieldArray[i].getName(), mfp);
}
attributeInitDone = !attributes.isEmpty();
}
public synchronized void initialize() {
if (!isInitialized()) {
CachedMethod[] methodArray = theCachedClass.getMethods();
for (int i = 0; i < methodArray.length; i++) {
final CachedMethod cachedMethod = methodArray[i];
Method reflectionMethod = cachedMethod.cachedMethod;
if (!reflectionMethod.getName().equals(CLOSURE_DO_CALL_METHOD)) continue;
MetaMethod method = createMetaMethod(cachedMethod);
closureMethods.add(method);
}
assignMethodChooser();
initialized = true;
}
}
private void assignMethodChooser() {
if (closureMethods.size() == 1) {
final MetaMethod doCall = (MetaMethod) closureMethods.get(0);
final CachedClass[] c = doCall.getParameterTypes();
int length = c.length;
if (length == 0) {
// no arg method
chooser = new MethodChooser() {
public Object chooseMethod(Class[] arguments, boolean coerce) {
if (arguments.length == 0) return doCall;
return null;
}
};
} else {
if (length == 1 && c[0].getCachedClass() == Object.class) {
// Object fits all, so simple dispatch rule here
chooser = new MethodChooser() {
public Object chooseMethod(Class[] arguments, boolean coerce) {
// <2, because foo() is same as foo(null)
if (arguments.length < 2) return doCall;
return null;
}
};
} else {
boolean allObject = true;
for (int i = 0; i < c.length - 1; i++) {
if (c[i].getCachedClass() != Object.class) {
allObject = false;
break;
}
}
if (allObject && c[c.length - 1].getCachedClass() == Object.class) {
// all arguments are object, so test only if argument number is correct
chooser = new MethodChooser() {
public Object chooseMethod(Class[] arguments, boolean coerce) {
if (arguments.length == c.length) return doCall;
return null;
}
};
} else {
if (allObject && c[c.length - 1].getCachedClass() == Object[].class) {
// all arguments are Object but last, which is a vargs argument, that
// will fit all, so jsut test if the number of argument is equal or
// more than the parameters we have.
final int minimumLength = c.length - 2;
chooser = new MethodChooser() {
public Object chooseMethod(Class[] arguments, boolean coerce) {
if (arguments.length > minimumLength) return doCall;
return null;
}
};
} else {
// general case for single method
chooser = new MethodChooser() {
public Object chooseMethod(Class[] arguments, boolean coerce) {
if (MetaClassHelper.isValidMethod(doCall, arguments, coerce)) {
return doCall;
}
return null;
}
};
}
}
}
}
} else if (closureMethods.size() == 2) {
MetaMethod m0 = null, m1 = null;
for (int i = 0; i != closureMethods.size(); ++i) {
MetaMethod m = (MetaMethod) closureMethods.get(i);
CachedClass[] c = m.getParameterTypes();
if (c.length == 0) {
m0 = m;
} else {
if (c.length == 1 && c[0].getCachedClass() == Object.class) {
m1 = m;
}
}
}
if (m0 != null && m1 != null) {
// standard closure (2 methods because "it" is with default null)
chooser = new StandardClosureChooser(m0, m1);
}
}
if (chooser == null) {
// standard chooser for cases if it is not a single method and if it is
// not the standard closure.
chooser = new NormalMethodChooser(theClass, closureMethods);
}
}
private MetaMethod createMetaMethod(final CachedMethod method) {
if (method.canBeCalledByReflector())
return StdMetaMethod.createStdMetaMethod(method);
else
return ReflectionMetaMethod.createReflectionMetaMethod(method);
}
private void generateReflector() {
// if (GroovySystem.isUseReflection())
// return;
//
// reflector = ((MetaClassRegistryImpl) registry).loadReflector(theClass, closureMethods);
// if (reflector == null) {
// throw new RuntimeException("Should have a reflector for " + theClass.getName());
// }
// // lets set the reflector on all the methods
// for (Iterator iter = closureMethods.iterator(); iter.hasNext();) {
// StdMetaMethod metaMethod = (StdMetaMethod) iter.next();
// metaMethod.setReflector(reflector);
// }
}
private MetaClass lookupObjectMetaClass(Object object) {
if (object instanceof GroovyObject) {
GroovyObject go = (GroovyObject) object;
return go.getMetaClass();
}
Class ownerClass = object.getClass();
if (ownerClass == Class.class) ownerClass = (Class) object;
MetaClass metaClass = registry.getMetaClass(ownerClass);
return metaClass;
}
public List getMethods() {
List answer = CLOSURE_METACLASS.getMetaMethods();
answer.addAll(closureMethods.toList());
return answer;
}
public List getMetaMethods() {
return CLOSURE_METACLASS.getMetaMethods();
}
public List getProperties() {
return CLOSURE_METACLASS.getProperties();
}
public MetaMethod pickMethod(String name, Class[] argTypes) {
if (argTypes == null) argTypes = new Class[0];
if (name.equals(CLOSURE_CALL_METHOD) || name.equals(CLOSURE_DO_CALL_METHOD)) {
return pickClosureMethod(argTypes);
}
return CLOSURE_METACLASS.getMetaMethod(name, argTypes);
}
public MetaMethod retrieveStaticMethod(String methodName, Class[] arguments) {
return null;
}
protected boolean isInitialized() {
return initialized;
}
public MetaMethod getStaticMetaMethod(String name, Object[] args) {
return CLOSURE_METACLASS.getStaticMetaMethod(name, args);
}
public MetaMethod getStaticMetaMethod(String name, Class[] argTypes) {
return CLOSURE_METACLASS.getStaticMetaMethod(name, argTypes);
}
public Object getProperty(Class sender, Object object, String name, boolean useSuper, boolean fromInsideClass) {
if (object instanceof Class) {
return getStaticMetaClass().getProperty(sender, object, name, useSuper, fromInsideClass);
} else {
return CLOSURE_METACLASS.getProperty(sender, object, name, useSuper, fromInsideClass);
}
}
public Object getAttribute(Class sender, Object object, String attribute, boolean useSuper, boolean fromInsideClass) {
if (object instanceof Class) {
return getStaticMetaClass().getAttribute(sender, object, attribute, useSuper);
} else {
if (!attributeInitDone) initAttributes();
MetaFieldProperty mfp = (MetaFieldProperty) attributes.get(attribute);
if (mfp == null) {
return CLOSURE_METACLASS.getAttribute(sender, object, attribute, useSuper);
} else {
return mfp.getProperty(object);
}
}
}
public void setAttribute(Class sender, Object object, String attribute,
Object newValue, boolean useSuper, boolean fromInsideClass) {
if (object instanceof Class) {
getStaticMetaClass().setAttribute(sender, object, attribute, newValue, useSuper, fromInsideClass);
} else {
if (!attributeInitDone) initAttributes();
MetaFieldProperty mfp = (MetaFieldProperty) attributes.get(attribute);
if (mfp == null) {
CLOSURE_METACLASS.setAttribute(sender, object, attribute, newValue, useSuper, fromInsideClass);
} else {
mfp.setProperty(object, newValue);
}
}
}
public Object invokeStaticMethod(Object object, String methodName, Object[] arguments) {
return getStaticMetaClass().invokeMethod(Class.class, object, methodName, arguments, false, false);
}
public void setProperty(Class sender, Object object, String name, Object newValue, boolean useSuper, boolean fromInsideClass) {
if (object instanceof Class) {
getStaticMetaClass().setProperty(sender, object, name, newValue, useSuper, fromInsideClass);
} else {
CLOSURE_METACLASS.setProperty(sender, object, name, newValue, useSuper, fromInsideClass);
}
}
public MetaMethod getMethodWithoutCaching(Class sender, String methodName, Class[] arguments, boolean isCallToSuper) {
throw new UnsupportedOperationException();
}
public void setProperties(Object bean, Map map) {
throw new UnsupportedOperationException();
}
private Object invokeConstructor(Class at, Object[] arguments) {
throw new UnsupportedOperationException();
}
public void addMetaBeanProperty(MetaBeanProperty mp) {
throw new UnsupportedOperationException();
}
public void addMetaMethod(MetaMethod method) {
throw new UnsupportedOperationException();
}
public void addNewInstanceMethod(Method method) {
throw new UnsupportedOperationException();
}
public void addNewStaticMethod(Method method) {
throw new UnsupportedOperationException();
}
public Constructor retrieveConstructor(Class[] arguments) {
throw new UnsupportedOperationException();
}
}