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The Adobe Experience Manager SDK
/*
* 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 javax.el;
import java.lang.ref.WeakReference;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
class Util {
private static final Class[] EMPTY_CLASS_ARRAY = new Class[0];
private static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
/**
* Checks whether the supplied Throwable is one that needs to be
* rethrown and swallows all others.
* @param t the Throwable to check
*/
static void handleThrowable(Throwable t) {
if (t instanceof ThreadDeath) {
throw (ThreadDeath) t;
}
if (t instanceof VirtualMachineError) {
throw (VirtualMachineError) t;
}
// All other instances of Throwable will be silently swallowed
}
static String message(ELContext context, String name, Object... props) {
Locale locale = null;
if (context != null) {
locale = context.getLocale();
}
if (locale == null) {
locale = Locale.getDefault();
if (locale == null) {
return "";
}
}
ResourceBundle bundle = ResourceBundle.getBundle(
"javax.el.LocalStrings", locale);
try {
String template = bundle.getString(name);
if (props != null) {
template = MessageFormat.format(template, props);
}
return template;
} catch (MissingResourceException e) {
return "Missing Resource: '" + name + "' for Locale " + locale.getDisplayName();
}
}
private static final CacheValue nullTcclFactory = new CacheValue();
private static final ConcurrentMap factoryCache =
new ConcurrentHashMap();
/**
* Provides a per class loader cache of ExpressionFactory instances without
* pinning any in memory as that could trigger a memory leak.
*/
static ExpressionFactory getExpressionFactory() {
ClassLoader tccl = getContextClassLoader();
CacheValue cacheValue = null;
ExpressionFactory factory = null;
if (tccl == null) {
cacheValue = nullTcclFactory;
} else {
CacheKey key = new CacheKey(tccl);
cacheValue = factoryCache.get(key);
if (cacheValue == null) {
CacheValue newCacheValue = new CacheValue();
cacheValue = factoryCache.putIfAbsent(key, newCacheValue);
if (cacheValue == null) {
cacheValue = newCacheValue;
}
}
}
final Lock readLock = cacheValue.getLock().readLock();
readLock.lock();
try {
factory = cacheValue.getExpressionFactory();
} finally {
readLock.unlock();
}
if (factory == null) {
final Lock writeLock = cacheValue.getLock().writeLock();
writeLock.lock();
try {
factory = cacheValue.getExpressionFactory();
if (factory == null) {
factory = ExpressionFactory.newInstance();
cacheValue.setExpressionFactory(factory);
}
} finally {
writeLock.unlock();
}
}
return factory;
}
/**
* Key used to cache default ExpressionFactory information per class
* loader. The class loader reference is never {@code null}, because
* {@code null} tccl is handled separately.
*/
private static class CacheKey {
private final int hash;
private final WeakReference ref;
public CacheKey(ClassLoader key) {
hash = key.hashCode();
ref = new WeakReference(key);
}
@Override
public int hashCode() {
return hash;
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof CacheKey)) {
return false;
}
ClassLoader thisKey = ref.get();
if (thisKey == null) {
return false;
}
return thisKey == ((CacheKey) obj).ref.get();
}
}
private static class CacheValue {
private final ReadWriteLock lock = new ReentrantReadWriteLock();
private WeakReference ref;
public CacheValue() {
}
public ReadWriteLock getLock() {
return lock;
}
public ExpressionFactory getExpressionFactory() {
return ref != null ? ref.get() : null;
}
public void setExpressionFactory(ExpressionFactory factory) {
ref = new WeakReference(factory);
}
}
/*
* This method duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
static Method findMethod(Class clazz, String methodName,
Class[] paramTypes, Object[] paramValues) {
if (clazz == null || methodName == null) {
throw new MethodNotFoundException(
message(null, "util.method.notfound", clazz, methodName,
paramString(paramTypes)));
}
if (paramTypes == null) {
paramTypes = getTypesFromValues(paramValues);
}
Method[] methods = clazz.getMethods();
List wrappers = Wrapper.wrap(methods, methodName);
Wrapper result = findWrapper(clazz, wrappers, methodName, paramTypes, paramValues);
return getMethod(clazz, (Method) result.unWrap());
}
/*
* This method duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
@SuppressWarnings("null")
private static Wrapper findWrapper(Class clazz, List wrappers,
String name, Class[] paramTypes, Object[] paramValues) {
Map candidates = new HashMap();
int paramCount = paramTypes.length;
for (Wrapper w : wrappers) {
Class[] mParamTypes = w.getParameterTypes();
int mParamCount;
if (mParamTypes == null) {
mParamCount = 0;
} else {
mParamCount = mParamTypes.length;
}
// Check the number of parameters
// Multiple tests to improve readability
if (!w.isVarArgs() && paramCount != mParamCount) {
// Method has wrong number of parameters
continue;
}
if (w.isVarArgs() && paramCount < mParamCount -1) {
// Method has wrong number of parameters
continue;
}
if (w.isVarArgs() && paramCount == mParamCount && paramValues != null &&
paramValues.length > paramCount && !paramTypes[mParamCount -1].isArray()) {
// Method arguments don't match
continue;
}
if (w.isVarArgs() && paramCount > mParamCount && paramValues != null &&
paramValues.length != paramCount) {
// Might match a different varargs method
continue;
}
if (!w.isVarArgs() && paramValues != null && paramCount != paramValues.length) {
// Might match a different varargs method
continue;
}
// Check the parameters match
int exactMatch = 0;
int assignableMatch = 0;
int coercibleMatch = 0;
boolean noMatch = false;
for (int i = 0; i < mParamCount; i++) {
// Can't be null
if (w.isVarArgs() && i == (mParamCount - 1)) {
if (i == paramCount || (paramValues != null && paramValues.length == i)) {
// Nothing is passed as varargs
assignableMatch++;
break;
}
Class varType = mParamTypes[i].getComponentType();
for (int j = i; j < paramCount; j++) {
if (isAssignableFrom(paramTypes[j], varType)) {
assignableMatch++;
} else {
if (paramValues == null) {
noMatch = true;
break;
} else {
if (isCoercibleFrom(paramValues[j], varType)) {
coercibleMatch++;
} else {
noMatch = true;
break;
}
}
}
// Don't treat a varArgs match as an exact match, it can
// lead to a varArgs method matching when the result
// should be ambiguous
}
} else {
if (mParamTypes[i].equals(paramTypes[i])) {
exactMatch++;
} else if (paramTypes[i] != null && isAssignableFrom(paramTypes[i], mParamTypes[i])) {
assignableMatch++;
} else {
if (paramValues == null) {
noMatch = true;
break;
} else {
if (isCoercibleFrom(paramValues[i], mParamTypes[i])) {
coercibleMatch++;
} else {
noMatch = true;
break;
}
}
}
}
}
if (noMatch) {
continue;
}
// If a method is found where every parameter matches exactly,
// return it
if (exactMatch == paramCount) {
return w;
}
candidates.put(w, new MatchResult(
exactMatch, assignableMatch, coercibleMatch, w.isBridge()));
}
// Look for the method that has the highest number of parameters where
// the type matches exactly
MatchResult bestMatch = new MatchResult(0, 0, 0, false);
Wrapper match = null;
boolean multiple = false;
for (Map.Entry entry : candidates.entrySet()) {
int cmp = entry.getValue().compareTo(bestMatch);
if (cmp > 0 || match == null) {
bestMatch = entry.getValue();
match = entry.getKey();
multiple = false;
} else if (cmp == 0) {
multiple = true;
}
}
if (multiple) {
if (bestMatch.getExact() == paramCount - 1) {
// Only one parameter is not an exact match - try using the
// super class
match = resolveAmbiguousWrapper(candidates.keySet(), paramTypes);
} else {
match = null;
}
if (match == null) {
// If multiple methods have the same matching number of parameters
// the match is ambiguous so throw an exception
throw new MethodNotFoundException(message(
null, "util.method.ambiguous", clazz, name,
paramString(paramTypes)));
}
}
// Handle case where no match at all was found
if (match == null) {
throw new MethodNotFoundException(message(
null, "util.method.notfound", clazz, name,
paramString(paramTypes)));
}
return match;
}
private static final String paramString(Class[] types) {
if (types != null) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < types.length; i++) {
if (types[i] == null) {
sb.append("null, ");
} else {
sb.append(types[i].getName()).append(", ");
}
}
if (sb.length() > 2) {
sb.setLength(sb.length() - 2);
}
return sb.toString();
}
return null;
}
/*
* This method duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
private static Wrapper resolveAmbiguousWrapper(Set candidates,
Class[] paramTypes) {
// Identify which parameter isn't an exact match
Wrapper w = candidates.iterator().next();
int nonMatchIndex = 0;
Class nonMatchClass = null;
for (int i = 0; i < paramTypes.length; i++) {
if (w.getParameterTypes()[i] != paramTypes[i]) {
nonMatchIndex = i;
nonMatchClass = paramTypes[i];
break;
}
}
if (nonMatchClass == null) {
// Null will always be ambiguous
return null;
}
for (Wrapper c : candidates) {
if (c.getParameterTypes()[nonMatchIndex] ==
paramTypes[nonMatchIndex]) {
// Methods have different non-matching parameters
// Result is ambiguous
return null;
}
}
// Can't be null
Class superClass = nonMatchClass.getSuperclass();
while (superClass != null) {
for (Wrapper c : candidates) {
if (c.getParameterTypes()[nonMatchIndex].equals(superClass)) {
// Found a match
return c;
}
}
superClass = superClass.getSuperclass();
}
// Treat instances of Number as a special case
Wrapper match = null;
if (Number.class.isAssignableFrom(nonMatchClass)) {
for (Wrapper c : candidates) {
Class candidateType = c.getParameterTypes()[nonMatchIndex];
if (Number.class.isAssignableFrom(candidateType) ||
candidateType.isPrimitive()) {
if (match == null) {
match = c;
} else {
// Match still ambiguous
match = null;
break;
}
}
}
}
return match;
}
/*
* This method duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
static boolean isAssignableFrom(Class src, Class target) {
// src will always be an object
// Short-cut. null is always assignable to an object and in EL null
// can always be coerced to a valid value for a primitive
if (src == null) {
return true;
}
Class targetClass;
if (target.isPrimitive()) {
if (target == Boolean.TYPE) {
targetClass = Boolean.class;
} else if (target == Character.TYPE) {
targetClass = Character.class;
} else if (target == Byte.TYPE) {
targetClass = Byte.class;
} else if (target == Short.TYPE) {
targetClass = Short.class;
} else if (target == Integer.TYPE) {
targetClass = Integer.class;
} else if (target == Long.TYPE) {
targetClass = Long.class;
} else if (target == Float.TYPE) {
targetClass = Float.class;
} else {
targetClass = Double.class;
}
} else {
targetClass = target;
}
return targetClass.isAssignableFrom(src);
}
/*
* This method duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
private static boolean isCoercibleFrom(Object src, Class target) {
// TODO: This isn't pretty but it works. Significant refactoring would
// be required to avoid the exception.
try {
getExpressionFactory().coerceToType(src, target);
} catch (ELException e) {
return false;
}
return true;
}
private static Class[] getTypesFromValues(Object[] values) {
if (values == null) {
return EMPTY_CLASS_ARRAY;
}
Class result[] = new Class[values.length];
for (int i = 0; i < values.length; i++) {
if (values[i] == null) {
result[i] = null;
} else {
result[i] = values[i].getClass();
}
}
return result;
}
/*
* This method duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
static Method getMethod(Class type, Method m) {
if (m == null || Modifier.isPublic(type.getModifiers())) {
return m;
}
Class[] inf = type.getInterfaces();
Method mp = null;
for (int i = 0; i < inf.length; i++) {
try {
mp = inf[i].getMethod(m.getName(), m.getParameterTypes());
mp = getMethod(mp.getDeclaringClass(), mp);
if (mp != null) {
return mp;
}
} catch (NoSuchMethodException e) {
// Ignore
}
}
Class sup = type.getSuperclass();
if (sup != null) {
try {
mp = sup.getMethod(m.getName(), m.getParameterTypes());
mp = getMethod(mp.getDeclaringClass(), mp);
if (mp != null) {
return mp;
}
} catch (NoSuchMethodException e) {
// Ignore
}
}
return null;
}
static Constructor findConstructor(Class clazz, Class[] paramTypes,
Object[] paramValues) {
String methodName = "";
if (clazz == null) {
throw new MethodNotFoundException(
message(null, "util.method.notfound", null, methodName,
paramString(paramTypes)));
}
if (paramTypes == null) {
paramTypes = getTypesFromValues(paramValues);
}
Constructor[] constructors = clazz.getConstructors();
List wrappers = Wrapper.wrap(constructors);
Wrapper result = findWrapper(clazz, wrappers, methodName, paramTypes, paramValues);
return getConstructor(clazz, (Constructor) result.unWrap());
}
static Constructor getConstructor(Class type, Constructor c) {
if (c == null || Modifier.isPublic(type.getModifiers())) {
return c;
}
Constructor cp = null;
Class sup = type.getSuperclass();
if (sup != null) {
try {
cp = sup.getConstructor(c.getParameterTypes());
cp = getConstructor(cp.getDeclaringClass(), cp);
if (cp != null) {
return cp;
}
} catch (NoSuchMethodException e) {
// Ignore
}
}
return null;
}
static Object[] buildParameters(Class[] parameterTypes,
boolean isVarArgs,Object[] params) {
ExpressionFactory factory = getExpressionFactory();
Object[] parameters = null;
if (parameterTypes.length > 0) {
parameters = new Object[parameterTypes.length];
int paramCount;
if (params == null) {
params = EMPTY_OBJECT_ARRAY;
}
paramCount = params.length;
if (isVarArgs) {
int varArgIndex = parameterTypes.length - 1;
// First argCount-1 parameters are standard
for (int i = 0; (i < varArgIndex); i++) {
parameters[i] = factory.coerceToType(params[i],
parameterTypes[i]);
}
// Last parameter is the varargs
Class varArgClass =
parameterTypes[varArgIndex].getComponentType();
final Object varargs = Array.newInstance(
varArgClass,
(paramCount - varArgIndex));
for (int i = (varArgIndex); i < paramCount; i++) {
Array.set(varargs, i - varArgIndex,
factory.coerceToType(params[i], varArgClass));
}
parameters[varArgIndex] = varargs;
} else {
parameters = new Object[parameterTypes.length];
for (int i = 0; i < parameterTypes.length; i++) {
parameters[i] = factory.coerceToType(params[i],
parameterTypes[i]);
}
}
}
return parameters;
}
static ClassLoader getContextClassLoader() {
ClassLoader tccl;
if (System.getSecurityManager() != null) {
PrivilegedAction pa = new PrivilegedGetTccl();
tccl = AccessController.doPrivileged(pa);
} else {
tccl = Thread.currentThread().getContextClassLoader();
}
return tccl;
}
private abstract static class Wrapper {
public static List wrap(Method[] methods, String name) {
List result = new ArrayList();
for (Method method : methods) {
if (method.getName().equals(name)) {
result.add(new MethodWrapper(method));
}
}
return result;
}
public static List wrap(Constructor[] constructors) {
List result = new ArrayList();
for (Constructor constructor : constructors) {
result.add(new ConstructorWrapper(constructor));
}
return result;
}
public abstract Object unWrap();
public abstract Class[] getParameterTypes();
public abstract boolean isVarArgs();
public abstract boolean isBridge();
}
private static class MethodWrapper extends Wrapper {
private final Method m;
public MethodWrapper(Method m) {
this.m = m;
}
@Override
public Object unWrap() {
return m;
}
@Override
public Class[] getParameterTypes() {
return m.getParameterTypes();
}
@Override
public boolean isVarArgs() {
return m.isVarArgs();
}
@Override
public boolean isBridge() {
return m.isBridge();
}
}
private static class ConstructorWrapper extends Wrapper {
private final Constructor c;
public ConstructorWrapper(Constructor c) {
this.c = c;
}
@Override
public Object unWrap() {
return c;
}
@Override
public Class[] getParameterTypes() {
return c.getParameterTypes();
}
@Override
public boolean isVarArgs() {
return c.isVarArgs();
}
@Override
public boolean isBridge() {
return false;
}
}
/*
* This class duplicates code in org.apache.el.util.ReflectionUtil. When
* making changes keep the code in sync.
*/
private static class MatchResult implements Comparable {
private final int exact;
private final int assignable;
private final int coercible;
private final boolean bridge;
public MatchResult(int exact, int assignable, int coercible, boolean bridge) {
this.exact = exact;
this.assignable = assignable;
this.coercible = coercible;
this.bridge = bridge;
}
public int getExact() {
return exact;
}
public int getAssignable() {
return assignable;
}
public int getCoercible() {
return coercible;
}
public boolean isBridge() {
return bridge;
}
@Override
public int compareTo(MatchResult o) {
if (this.getExact() < o.getExact()) {
return -1;
} else if (this.getExact() > o.getExact()) {
return 1;
} else {
if (this.getAssignable() < o.getAssignable()) {
return -1;
} else if (this.getAssignable() > o.getAssignable()) {
return 1;
} else {
if (this.getCoercible() < o.getCoercible()) {
return -1;
} else if (this.getCoercible() > o.getCoercible()) {
return 1;
} else {
// The nature of bridge methods is such that it actually
// doesn't matter which one we pick as long as we pick
// one. That said, pick the 'right' one (the non-bridge
// one) anyway.
if (o.isBridge() && !this.isBridge()) {
return 1;
} else if (!o.isBridge() && this.isBridge()) {
return -1;
} else {
return 0;
}
}
}
}
}
@Override
public boolean equals(Object o)
{
return o == this || (null != o &&
this.getClass().equals(o.getClass()) &&
((MatchResult)o).getExact() == this.getExact() &&
((MatchResult)o).getAssignable() == this.getAssignable() &&
((MatchResult)o).getCoercible() == this.getCoercible() &&
((MatchResult)o).isBridge() == this.isBridge());
}
@Override
public int hashCode()
{
return (this.isBridge() ? 1 << 24 : 0) ^
this.getExact() << 16 ^
this.getAssignable() << 8 ^
this.getCoercible();
}
}
private static class PrivilegedGetTccl implements PrivilegedAction {
@Override
public ClassLoader run() {
return Thread.currentThread().getContextClassLoader();
}
}
}