/***
* Copyright (c) 2009 Caelum - www.caelum.com.br/opensource All rights reserved.
*
* 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 br.com.caelum.vraptor.view;
import static br.com.caelum.vraptor.util.StringUtils.capitalize;
import static java.util.Arrays.fill;
import static java.util.Collections.sort;
import static javassist.CtNewMethod.abstractMethod;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
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.ReentrantLock;
import javassist.CannotCompileException;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.NotFoundException;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import javax.inject.Named;
import javax.servlet.ServletContext;
import net.vidageek.mirror.dsl.Mirror;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import br.com.caelum.vraptor.controller.BeanClass;
import br.com.caelum.vraptor.http.route.Router;
import br.com.caelum.vraptor.proxy.MethodInvocation;
import br.com.caelum.vraptor.proxy.Proxifier;
import br.com.caelum.vraptor.proxy.ProxyCreationException;
import br.com.caelum.vraptor.proxy.SuperMethod;
import br.com.caelum.vraptor.util.StringUtils;
import com.google.common.collect.ForwardingMap;
/**
* View helper for generating uris
* @author Lucas Cavalcanti
* @since 3.4.0
*
*/
@Named("linkTo")
@ApplicationScoped
public class LinkToHandler extends ForwardingMap<Class<?>, Object> {
private static final Logger logger = LoggerFactory.getLogger(LinkToHandler.class);
private final ServletContext context;
private final Router router;
private final Proxifier proxifier;
private ConcurrentMap<Class<?>, Class<?>> interfaces = new ConcurrentHashMap<>();
/**
* @deprecated CDI eyes only
*/
protected LinkToHandler() {
this(null, null, null);
}
@Inject
public LinkToHandler(ServletContext context, Router router, Proxifier proxifier) {
this.context = context;
this.router = router;
this.proxifier = proxifier;
}
@PostConstruct
public void start() {
logger.info("Registering linkTo component");
}
@Override
protected Map<Class<?>, Object> delegate() {
return Collections.emptyMap();
}
private Lock lock = new ReentrantLock();
@Override
public Object get(Object key) {
logger.debug("getting key {}", key);
BeanClass beanClass = (BeanClass) key;
final Class<?> controller = beanClass.getType();
Class<?> linkToInterface = interfaces.get(controller);
if (linkToInterface == null) {
logger.debug("interface not found, creating one {}", controller);
lock.lock();
try {
linkToInterface = interfaces.get(controller);
if (linkToInterface == null) {
String interfaceName = controller.getName() + "$linkTo";
linkToInterface = createLinkToInterface(controller, interfaceName);
interfaces.put(controller, linkToInterface);
logger.debug("created interface {} to {}", interfaceName, controller);
}
} finally {
lock.unlock();
}
}
return proxifier.proxify(linkToInterface, new MethodInvocation<Object>() {
@Override
public Object intercept(Object proxy, Method method, Object[] args, SuperMethod superMethod) {
String methodName = StringUtils.decapitalize(method.getName().replaceFirst("^get", ""));
List<Object> params = args.length == 0 ? Collections.emptyList() : Arrays.asList(args);
return new Linker(controller, methodName, params).getLink();
}
});
}
private Class<?> createLinkToInterface(final Class<?> controller, String interfaceName) {
try {
return Class.forName(interfaceName);
} catch (ClassNotFoundException e1) {
// ok, continue
}
final Set<CtMethod> used = new HashSet<>();
ClassPool pool = ClassPool.getDefault();
CtClass inter = pool.makeInterface(interfaceName);
try {
CtClass returnType = pool.get(String.class.getName());
CtClass objectType = pool.get(Object.class.getName());
for (Method m : getMethods(controller)) {
String name = m.getName();
CtClass[] params = createParameters(objectType, m.getParameterTypes().length);
CtClass[] empty = new CtClass[0];
for (int length = params.length; length >= 0; length--) {
CtMethod method = abstractMethod(returnType, m.getName(), Arrays.copyOf(params, length), empty, inter);
if (used.add(method)) {
inter.addMethod(method);
logger.debug("added method {} to interface {}", method.getName(), controller);
}
}
CtMethod getter = abstractMethod(returnType, String.format("get%s", capitalize(name)), empty, empty, inter);
if (used.add(getter)) {
inter.addMethod(getter);
logger.debug("added getter {} to interface {}", getter.getName(), controller);
}
}
return inter.toClass();
} catch (CannotCompileException | NotFoundException e) {
throw new ProxyCreationException(e);
}
}
private CtClass[] createParameters(CtClass objectType, int num) {
CtClass[] params = new CtClass[num];
fill(params, objectType);
return params;
}
private List<Method> getMethods(Class<?> controller) {
List<Method> methods = new ArrayList<>();
for (Method method : new Mirror().on(controller).reflectAll().methods()) {
if (!method.getDeclaringClass().equals(Object.class)) {
methods.add(method);
}
}
sort(methods, new SortByArgumentsLengthDesc());
return methods;
}
private final class SortByArgumentsLengthDesc implements Comparator<Method> {
@Override
public int compare(Method o1, Method o2) {
return Integer.compare(o2.getParameterTypes().length, o1.getParameterTypes().length);
}
}
class Linker {
private final List<Object> args;
private final String methodName;
private final Class<?> controller;
public Linker(Class<?> controller, String methodName, List<Object> args) {
this.controller = controller;
this.methodName = methodName;
this.args = args;
}
public String getLink() {
Method method = null;
if (countMethodsWithSameName() > 1) {
method = new Mirror().on(controller).reflect().method(methodName).withArgs(getClasses(args));
if (method == null && args.isEmpty()) {
throw new IllegalArgumentException("Ambiguous method '" + methodName + "' on " + controller + ". Try to add some parameters to resolve ambiguity, or use different method names.");
}
} else {
method = findMethodWithName(controller, methodName);
}
if(method == null) {
throw new IllegalArgumentException(
String.format("There are no methods on %s named '%s' that receives args of types %s",
controller, methodName, Arrays.toString(getClasses(args))));
}
return context.getContextPath() + router.urlFor(controller, method, getArgs(method));
}
private Object[] getArgs(Method method) {
int methodArity = method.getParameterTypes().length;
if (args.size() == methodArity) {
return args.toArray();
}
if (args.size() > methodArity) {
throw new IllegalArgumentException(String.format("linkTo param args must have the same or lower length as method param args. linkTo args: %d | method args: %d", args.size(), methodArity));
}
Object[] noMissingParamsArgs = new Object[methodArity];
System.arraycopy(args.toArray(), 0, noMissingParamsArgs, 0, args.size());
return noMissingParamsArgs;
}
private Method findMethodWithName(Class<?> type, String name) {
for (Method method : type.getDeclaredMethods()) {
if (!method.isBridge() && method.getName().equals(name)) {
return method;
}
}
if (type.getSuperclass().equals(Object.class)) {
return null;
}
return findMethodWithName(type.getSuperclass(), name);
}
private int countMethodsWithSameName() {
int amount = 0;
for (Method method : controller.getDeclaredMethods()) {
if (!method.isBridge() && method.getName().equals(methodName)) {
amount++;
}
}
return amount;
}
private Class<?>[] getClasses(List<Object> params) {
Class<?>[] classes = new Class<?>[params.size()];
for(int i = 0; i < params.size(); i ++) {
classes[i] = params.get(i).getClass();
}
return classes;
}
}
@PreDestroy
public void removeGeneratedClasses() {
ClassPool pool = ClassPool.getDefault();
for (Class<?> clazz : interfaces.values()) {
CtClass ctClass = pool.getOrNull(clazz.getName());
if (ctClass != null) {
ctClass.detach();
logger.debug("class {} is detached", clazz.getName());
}
}
}
}