/*
 * Copyright 2002-2013 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.beans;

import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Set;

import org.apache.commons.logging.LogFactory;

import org.springframework.core.BridgeMethodResolver;
import org.springframework.core.GenericTypeResolver;
import org.springframework.core.MethodParameter;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;

/**
 * Extension of the standard JavaBeans {@link PropertyDescriptor} class,
 * overriding {@code getPropertyType()} such that a generically declared
 * type variable will be resolved against the containing bean class.
 *
 * @author Juergen Hoeller
 * @since 2.5.2
 */
class GenericTypeAwarePropertyDescriptor extends PropertyDescriptor {

	private final Class<?> beanClass;

	private final Method readMethod;

	private final Method writeMethod;

	private final Class<?> propertyEditorClass;

	private volatile Set<Method> ambiguousWriteMethods;

	private Class<?> propertyType;

	private MethodParameter writeMethodParameter;


	public GenericTypeAwarePropertyDescriptor(Class<?> beanClass, String propertyName,
			Method readMethod, Method writeMethod, Class<?> propertyEditorClass)
			throws IntrospectionException {

		super(propertyName, null, null);
		this.beanClass = beanClass;
		this.propertyEditorClass = propertyEditorClass;

		Method readMethodToUse = BridgeMethodResolver.findBridgedMethod(readMethod);
		Method writeMethodToUse = BridgeMethodResolver.findBridgedMethod(writeMethod);
		if (writeMethodToUse == null && readMethodToUse != null) {
			// Fallback: Original JavaBeans introspection might not have found matching setter
			// method due to lack of bridge method resolution, in case of the getter using a
			// covariant return type whereas the setter is defined for the concrete property type.
			Method candidate = ClassUtils.getMethodIfAvailable(
					this.beanClass, "set" + StringUtils.capitalize(getName()), (Class<?>[]) null);
			if (candidate != null && candidate.getParameterTypes().length == 1) {
				writeMethodToUse = candidate;
			}
		}
		this.readMethod = readMethodToUse;
		this.writeMethod = writeMethodToUse;

		if (this.writeMethod != null && this.readMethod == null) {
			// Write method not matched against read method: potentially ambiguous through
			// several overloaded variants, in which case an arbitrary winner has been chosen
			// by the JDK's JavaBeans Introspector...
			Set<Method> ambiguousCandidates = new HashSet<Method>();
			for (Method method : beanClass.getMethods()) {
				if (method.getName().equals(writeMethodToUse.getName()) &&
						!method.equals(writeMethodToUse) && !method.isBridge()) {
					ambiguousCandidates.add(method);
				}
			}
			if (!ambiguousCandidates.isEmpty()) {
				this.ambiguousWriteMethods = ambiguousCandidates;
			}
		}
	}

	public Class<?> getBeanClass() {
		return this.beanClass;
	}

	@Override
	public Method getReadMethod() {
		return this.readMethod;
	}

	@Override
	public Method getWriteMethod() {
		return this.writeMethod;
	}

	public Method getWriteMethodForActualAccess() {
		Set<Method> ambiguousCandidates = this.ambiguousWriteMethods;
		if (ambiguousCandidates != null) {
			this.ambiguousWriteMethods = null;
			LogFactory.getLog(GenericTypeAwarePropertyDescriptor.class).warn("Invalid JavaBean property '" +
					getName() + "' being accessed! Ambiguous write methods found next to actually used [" +
					this.writeMethod + "]: " + ambiguousCandidates);
		}
		return this.writeMethod;
	}

	@Override
	public Class<?> getPropertyEditorClass() {
		return this.propertyEditorClass;
	}

	@Override
	public synchronized Class<?> getPropertyType() {
		if (this.propertyType == null) {
			if (this.readMethod != null) {
				this.propertyType = GenericTypeResolver.resolveReturnType(this.readMethod, this.beanClass);
			}
			else {
				MethodParameter writeMethodParam = getWriteMethodParameter();
				if (writeMethodParam != null) {
					this.propertyType = writeMethodParam.getParameterType();
				}
				else {
					this.propertyType = super.getPropertyType();
				}
			}
		}
		return this.propertyType;
	}

	public synchronized MethodParameter getWriteMethodParameter() {
		if (this.writeMethod == null) {
			return null;
		}
		if (this.writeMethodParameter == null) {
			this.writeMethodParameter = new MethodParameter(this.writeMethod, 0);
			GenericTypeResolver.resolveParameterType(this.writeMethodParameter, this.beanClass);
		}
		return this.writeMethodParameter;
	}

}
