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package com.sun.jersey.core.spi.component;
import com.sun.jersey.core.reflection.AnnotatedMethod;
import com.sun.jersey.core.reflection.MethodList;
import com.sun.jersey.core.reflection.ReflectionHelper;
import com.sun.jersey.spi.inject.Injectable;
import com.sun.jersey.spi.inject.InjectableProviderContext;
import com.sun.jersey.spi.inject.Errors;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;
/**
* A constructor of a component.
*
* @param <T> the type to construct
* @author Paul.Sandoz@Sun.Com
*/
public class ComponentConstructor<T> {
/**
* A tuple of a constructor and the list of injectables associated with
* the parameters of the constructor.
*
* @param <T> the type to construct.
*/
private static class ConstructorInjectablePair<T> {
/**
* The constructor.
*/
private final Constructor<T> con;
/**
* The list of injectables associated with the parameters of the
* constructor;
*/
private final List<Injectable> is;
/**
* Create a new tuple of a constructor and list of injectables.
*
* @param con the constructor
* @param is the list of injectables.
*/
private ConstructorInjectablePair(Constructor<T> con, List<Injectable> is) {
this.con = con;
this.is = is;
}
}
private static class ConstructorComparator<T> implements Comparator<ConstructorInjectablePair<T>> {
@Override
public int compare(ConstructorInjectablePair<T> o1, ConstructorInjectablePair<T> o2) {
int p = Collections.frequency(o1.is, null) - Collections.frequency(o2.is, null);
if (p != 0)
return p;
return o2.con.getParameterTypes().length - o1.con.getParameterTypes().length;
}
}
private final InjectableProviderContext ipc;
private final Class<T> c;
private final List<Method> postConstructs;
private final ComponentInjector<T> ci;
public ComponentConstructor(InjectableProviderContext ipc, Class<T> c, ComponentInjector<T> ci) {
this.ipc = ipc;
this.c = c;
this.ci = ci;
this.postConstructs = getPostConstructMethods(c);
}
private static List<Method> getPostConstructMethods(Class c) {
Class postConstructClass = ReflectionHelper.classForName("javax.annotation.PostConstruct");
LinkedList<Method> list = new LinkedList<Method>();
HashSet<String> names = new HashSet<String>();
if (postConstructClass != null) {
MethodList methodList = new MethodList(c, true);
for (AnnotatedMethod m : methodList.
hasAnnotation(postConstructClass).
hasNumParams(0).
hasReturnType(void.class)) {
Method method = m.getMethod();
// only add method if not hidden/overridden
if (names.add(method.getName())) {
ReflectionHelper.setAccessibleMethod(method);
// methods from the superclass should go first, so inserting at the beginning
list.addFirst(method);
}
}
}
return list;
}
/**
* Get a new instance.
*
* @return a new instance.
*/
public T getInstance()
throws InstantiationException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException {
final int modifiers = c.getModifiers();
if (!Modifier.isPublic(modifiers)) {
Errors.nonPublicClass(c);
}
if (Modifier.isAbstract(modifiers)) {
if (Modifier.isInterface(modifiers)) {
Errors.interfaceClass(c);
} else {
Errors.abstractClass(c);
}
}
if (c.getEnclosingClass() != null && !Modifier.isStatic(modifiers)) {
Errors.innerClass(c);
}
if (Modifier.isPublic(modifiers) && !Modifier.isAbstract(modifiers)) {
if (c.getConstructors().length == 0) {
Errors.nonPublicConstructor(c);
}
}
final T t = _getInstance();
ci.inject(t);
for (Method postConstruct : postConstructs) {
postConstruct.invoke(t);
}
return t;
}
private T _getInstance()
throws InstantiationException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException {
ConstructorInjectablePair<T> cip = getConstructor();
if (cip == null || cip.is.isEmpty()) {
return c.newInstance();
} else {
if (cip.is.contains(null)) {
// Missing dependency
for (int i = 0; i < cip.is.size(); i++) {
if (cip.is.get(i) == null) {
Errors.missingDependency(cip.con, i);
}
}
}
Object[] params = new Object[cip.is.size()];
int i = 0;
for (Injectable injectable : cip.is) {
if (injectable != null)
params[i++] = injectable.getValue();
}
return cip.con.newInstance(params);
}
}
/**
* Get the most suitable constructor. The constructor with the most
* parameters and that has the most parameters associated with
* Injectable instances will be chosen.
*
* @param <T> The type to construct.
* @param c the class to instantiate.
* @return a list of constructor and list of injectables for the constructor
* parameters.
*/
private ConstructorInjectablePair<T> getConstructor() {
if (c.getConstructors().length == 0)
return null;
SortedSet<ConstructorInjectablePair<T>> cs = new TreeSet<ConstructorInjectablePair<T>>(
new ConstructorComparator());
AnnotatedContext aoc = new AnnotatedContext();
for (Constructor con : c.getConstructors()) {
List<Injectable> is = new ArrayList<Injectable>();
int ps = con.getParameterTypes().length;
aoc.setAccessibleObject(con);
for (int p = 0; p < ps; p++) {
Type pgtype = con.getGenericParameterTypes()[p];
Annotation[] as = con.getParameterAnnotations()[p];
aoc.setAnnotations(as);
Injectable i = null;
for (Annotation a : as) {
i = ipc.getInjectable(
a.annotationType(), aoc, a, pgtype,
ComponentScope.UNDEFINED_SINGLETON);
}
is.add(i);
}
cs.add(new ConstructorInjectablePair<T>(con, is));
}
return cs.first();
}
}