/*
 * Copyright 2002-2008 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.springframework.web.bind.annotation.support;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;

import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.SessionAttributes;

/**
 * Support class for resolving web method annotations in a handler type.
 * Processes <code>@RequestMapping</code>, <code>@InitBinder</code>,
 * <code>@ModelAttribute</code> and <code>@SessionAttributes</code>.
 *
 * <p>Used by {@link org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter}
 * and {@link org.springframework.web.portlet.mvc.annotation.AnnotationMethodHandlerAdapter}.
 *
 * @author Juergen Hoeller
 * @since 2.5.2
 * @see org.springframework.web.bind.annotation.RequestMapping
 * @see org.springframework.web.bind.annotation.InitBinder
 * @see org.springframework.web.bind.annotation.ModelAttribute
 * @see org.springframework.web.bind.annotation.SessionAttributes
 */
public class HandlerMethodResolver {

	private final Set<Method> handlerMethods = new LinkedHashSet<Method>();

	private final Set<Method> initBinderMethods = new LinkedHashSet<Method>();

	private final Set<Method> modelAttributeMethods = new LinkedHashSet<Method>();

	private final RequestMapping typeLevelMapping;

	private final boolean sessionAttributesFound;

	private final Set<String> sessionAttributeNames = new HashSet<String>();

	private final Set<Class> sessionAttributeTypes = new HashSet<Class>();

	private final Set<String> actualSessionAttributeNames = Collections.synchronizedSet(new HashSet<String>(4));


	/**
	 * Create a new HandlerMethodResolver for the specified handler type.
	 * @param handlerType the handler class to introspect
	 */
	public HandlerMethodResolver(final Class<?> handlerType) {
		ReflectionUtils.doWithMethods(handlerType, new ReflectionUtils.MethodCallback() {
			public void doWith(Method method) {
				if (method.isAnnotationPresent(RequestMapping.class)) {
					handlerMethods.add(ClassUtils.getMostSpecificMethod(method, handlerType));
				}
				else if (method.isAnnotationPresent(InitBinder.class)) {
					initBinderMethods.add(ClassUtils.getMostSpecificMethod(method, handlerType));
				}
				else if (method.isAnnotationPresent(ModelAttribute.class)) {
					modelAttributeMethods.add(ClassUtils.getMostSpecificMethod(method, handlerType));
				}
			}
		});
		this.typeLevelMapping = handlerType.getAnnotation(RequestMapping.class);
		SessionAttributes sessionAttributes = handlerType.getAnnotation(SessionAttributes.class);
		this.sessionAttributesFound = (sessionAttributes != null);
		if (this.sessionAttributesFound) {
			this.sessionAttributeNames.addAll(Arrays.asList(sessionAttributes.value()));
			this.sessionAttributeTypes.addAll(Arrays.asList(sessionAttributes.types()));
		}
	}


	public final boolean hasHandlerMethods() {
		return !this.handlerMethods.isEmpty();
	}

	public final Set<Method> getHandlerMethods() {
		return this.handlerMethods;
	}

	public final Set<Method> getInitBinderMethods() {
		return this.initBinderMethods;
	}

	public final Set<Method> getModelAttributeMethods() {
		return this.modelAttributeMethods;
	}

	public boolean hasTypeLevelMapping() {
		return (this.typeLevelMapping != null);
	}

	public RequestMapping getTypeLevelMapping() {
		return this.typeLevelMapping;
	}

	public boolean hasSessionAttributes() {
		return this.sessionAttributesFound;
	}

	public boolean isSessionAttribute(String attrName, Class attrType) {
		if (this.sessionAttributeNames.contains(attrName) || this.sessionAttributeTypes.contains(attrType)) {
			this.actualSessionAttributeNames.add(attrName);
			return true;
		}
		else {
			return false;
		}
	}

	public Set<String> getActualSessionAttributeNames() {
		return this.actualSessionAttributeNames;
	}

}