/**
* 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 org.apache.camel.component.bean;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.camel.Body;
import org.apache.camel.CamelContext;
import org.apache.camel.Exchange;
import org.apache.camel.Expression;
import org.apache.camel.Header;
import org.apache.camel.Headers;
import org.apache.camel.Message;
import org.apache.camel.NoTypeConversionAvailableException;
import org.apache.camel.OutHeaders;
import org.apache.camel.Properties;
import org.apache.camel.Property;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.builder.ExpressionBuilder;
import org.apache.camel.language.LanguageAnnotation;
import org.apache.camel.spi.Registry;
import org.apache.camel.util.ObjectHelper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import static org.apache.camel.util.ExchangeHelper.convertToType;
/**
* Represents the metadata about a bean type created via a combination of
* introspection and annotations together with some useful sensible defaults
*
* @version $Revision: 707928 $
*/
public class BeanInfo {
private static final transient Log LOG = LogFactory.getLog(BeanInfo.class);
private final CamelContext camelContext;
private Class type;
private ParameterMappingStrategy strategy;
private Map<String, MethodInfo> operations = new ConcurrentHashMap<String, MethodInfo>();
private MethodInfo defaultMethod;
private List<MethodInfo> operationsWithBody = new ArrayList<MethodInfo>();
private List<MethodInfo> operationsWithCustomAnnotation = new ArrayList<MethodInfo>();
private Map<Method, MethodInfo> methodMap = new HashMap<Method, MethodInfo>();
private BeanInfo superBeanInfo;
public BeanInfo(CamelContext camelContext, Class type) {
this(camelContext, type, createParameterMappingStrategy(camelContext));
}
public BeanInfo(CamelContext camelContext, Class type, ParameterMappingStrategy strategy) {
this.camelContext = camelContext;
this.type = type;
this.strategy = strategy;
introspect(getType());
if (operations.size() == 1) {
Collection<MethodInfo> methodInfos = operations.values();
for (MethodInfo methodInfo : methodInfos) {
defaultMethod = methodInfo;
}
}
}
public Class getType() {
return type;
}
public CamelContext getCamelContext() {
return camelContext;
}
public MethodInvocation createInvocation(Method method, Object pojo, Exchange exchange)
throws RuntimeCamelException {
MethodInfo methodInfo = introspect(type, method);
if (methodInfo != null) {
return methodInfo.createMethodInvocation(pojo, exchange);
}
return null;
}
public MethodInvocation createInvocation(Object pojo, Exchange exchange) throws RuntimeCamelException,
AmbiguousMethodCallException {
MethodInfo methodInfo = null;
// TODO use some other mechanism?
String name = exchange.getIn().getHeader(BeanProcessor.METHOD_NAME, String.class);
if (name != null) {
methodInfo = operations.get(name);
}
if (methodInfo == null) {
methodInfo = chooseMethod(pojo, exchange);
}
if (methodInfo == null) {
methodInfo = defaultMethod;
}
if (methodInfo != null) {
return methodInfo.createMethodInvocation(pojo, exchange);
}
return null;
}
protected void introspect(Class clazz) {
if (LOG.isTraceEnabled()) {
LOG.trace("Introspecting class: " + clazz);
}
Method[] methods = clazz.getDeclaredMethods();
for (Method method : methods) {
if (isValidMethod(clazz, method)) {
introspect(clazz, method);
}
}
Class superclass = clazz.getSuperclass();
if (superclass != null && !superclass.equals(Object.class)) {
introspect(superclass);
}
}
protected MethodInfo introspect(Class clazz, Method method) {
if (LOG.isTraceEnabled()) {
LOG.trace("Introspecting class: " + clazz + ", method: " + method);
}
String opName = method.getName();
MethodInfo methodInfo = createMethodInfo(clazz, method);
// methods already registered should be prefered to use instead of super classes of existing methods
// we want to us the method from the sub class over super classes, so if we have already registered
// the method then use it (we are traversing upwards: sub (child) -> super (farther) )
MethodInfo existingMethodInfo = overridesExistingMethod(methodInfo);
if (existingMethodInfo != null) {
if (LOG.isTraceEnabled()) {
LOG.trace("This method is already overriden in a subclass, so the method from the sub class is prefered: " + existingMethodInfo);
}
return existingMethodInfo;
}
if (LOG.isTraceEnabled()) {
LOG.trace("Adding operation: " + opName + " for method: " + methodInfo);
}
operations.put(opName, methodInfo);
if (methodInfo.hasBodyParameter()) {
operationsWithBody.add(methodInfo);
}
if (methodInfo.isHasCustomAnnotation() && !methodInfo.hasBodyParameter()) {
operationsWithCustomAnnotation.add(methodInfo);
}
// must add to method map last otherwise we break stuff
methodMap.put(method, methodInfo);
return methodInfo;
}
/**
* Does the given method info override an existing method registered before (from a subclass)
*
* @param methodInfo the method to test
* @return the already registered method to use, null if not overriding any
*/
private MethodInfo overridesExistingMethod(MethodInfo methodInfo) {
for (MethodInfo info : methodMap.values()) {
// name test
if (!info.getMethod().getName().equals(methodInfo.getMethod().getName())) {
continue;
}
// parameter types
if (info.getMethod().getParameterTypes().length != methodInfo.getMethod().getParameterTypes().length) {
continue;
}
for (int i = 0; i < info.getMethod().getParameterTypes().length; i++) {
Class type1 = info.getMethod().getParameterTypes()[i];
Class type2 = methodInfo.getMethod().getParameterTypes()[i];
if (!type1.equals(type2)) {
continue;
}
}
// sanme name, same parameters, then its overrides an existing class
return info;
}
return null;
}
/**
* Returns the {@link MethodInfo} for the given method if it exists or null
* if there is no metadata available for the given method
*/
public MethodInfo getMethodInfo(Method method) {
MethodInfo answer = methodMap.get(method);
if (answer == null) {
// maybe the method is defined on a base class?
if (superBeanInfo == null && type != Object.class) {
Class superclass = type.getSuperclass();
if (superclass != null && superclass != Object.class) {
superBeanInfo = new BeanInfo(camelContext, superclass, strategy);
return superBeanInfo.getMethodInfo(method);
}
}
}
return answer;
}
protected MethodInfo createMethodInfo(Class clazz, Method method) {
Class[] parameterTypes = method.getParameterTypes();
Annotation[][] parametersAnnotations = method.getParameterAnnotations();
List<ParameterInfo> parameters = new ArrayList<ParameterInfo>();
List<ParameterInfo> bodyParameters = new ArrayList<ParameterInfo>();
boolean hasCustomAnnotation = false;
for (int i = 0; i < parameterTypes.length; i++) {
Class parameterType = parameterTypes[i];
Annotation[] parameterAnnotations = parametersAnnotations[i];
Expression expression = createParameterUnmarshalExpression(clazz, method, parameterType,
parameterAnnotations);
hasCustomAnnotation |= expression != null;
ParameterInfo parameterInfo = new ParameterInfo(i, parameterType, parameterAnnotations,
expression);
parameters.add(parameterInfo);
if (expression == null) {
hasCustomAnnotation |= ObjectHelper.hasAnnotation(parameterAnnotations, Body.class);
if (bodyParameters.isEmpty()) {
// lets assume its the body
if (Exchange.class.isAssignableFrom(parameterType)) {
expression = ExpressionBuilder.exchangeExpression();
} else {
expression = ExpressionBuilder.bodyExpression(parameterType);
}
parameterInfo.setExpression(expression);
bodyParameters.add(parameterInfo);
} else {
// will ignore the expression for parameter evaluation
}
}
}
// now lets add the method to the repository
// TODO allow an annotation to expose the operation name to use
/* if (method.getAnnotation(Operation.class) != null) { String name =
* method.getAnnotation(Operation.class).name(); if (name != null &&
* name.length() > 0) { opName = name; } }
*/
MethodInfo methodInfo = new MethodInfo(clazz, method, parameters, bodyParameters, hasCustomAnnotation);
return methodInfo;
}
/**
* Lets try choose one of the available methods to invoke if we can match
* the message body to the body parameter
*
* @param pojo the bean to invoke a method on
* @param exchange the message exchange
* @return the method to invoke or null if no definitive method could be
* matched
*/
protected MethodInfo chooseMethod(Object pojo, Exchange exchange) throws AmbiguousMethodCallException {
if (operationsWithBody.size() == 1) {
return operationsWithBody.get(0);
} else if (!operationsWithBody.isEmpty()) {
return chooseMethodWithMatchingBody(exchange, operationsWithBody);
} else if (operationsWithCustomAnnotation.size() == 1) {
return operationsWithCustomAnnotation.get(0);
}
return null;
}
protected MethodInfo chooseMethodWithMatchingBody(Exchange exchange, Collection<MethodInfo> operationList) throws AmbiguousMethodCallException {
// lets see if we can find a method who's body param type matches the message body
Message in = exchange.getIn();
Object body = in.getBody();
if (body != null) {
Class bodyType = body.getClass();
if (LOG.isTraceEnabled()) {
LOG.trace("Matching for method with a single parameter that matches type: " + bodyType.getCanonicalName());
}
List<MethodInfo> possibles = new ArrayList<MethodInfo>();
for (MethodInfo methodInfo : operationList) {
// TODO: AOP proxies have additioan methods - consider having a static
// method exclude list to skip all known AOP proxy methods
// TODO: This class could use some TRACE logging
// test for MEP pattern matching
boolean out = exchange.getPattern().isOutCapable();
if (out && methodInfo.isReturnTypeVoid()) {
// skip this method as the MEP is Out so the method must return someting
continue;
}
// try to match the arguments
if (methodInfo.bodyParameterMatches(bodyType)) {
possibles.add(methodInfo);
}
}
if (possibles.size() == 1) {
return possibles.get(0);
} else if (possibles.isEmpty()) {
// lets try converting
Object newBody = null;
MethodInfo matched = null;
for (MethodInfo methodInfo : operationList) {
Object value = null;
try {
value = convertToType(exchange, methodInfo.getBodyParameterType(), body);
if (value != null) {
if (newBody != null) {
throw new AmbiguousMethodCallException(exchange, Arrays.asList(matched,
methodInfo));
} else {
newBody = value;
matched = methodInfo;
}
}
} catch (NoTypeConversionAvailableException e) {
// we can safely ignore this exception as we want a behaviour similar to
// that if convertToType return null
}
}
if (matched != null) {
in.setBody(newBody);
return matched;
}
} else {
// if we only have a single method with custom annotations, lets use that one
if (operationsWithCustomAnnotation.size() == 1) {
return operationsWithCustomAnnotation.get(0);
}
return chooseMethodWithCustomAnnotations(exchange, possibles);
}
}
// no match so return null
return null;
}
protected MethodInfo chooseMethodWithCustomAnnotations(Exchange exchange, Collection<MethodInfo> possibles) throws AmbiguousMethodCallException {
// if we have only one method with custom annotations lets choose that
MethodInfo chosen = null;
for (MethodInfo possible : possibles) {
if (possible.isHasCustomAnnotation()) {
if (chosen != null) {
chosen = null;
break;
} else {
chosen = possible;
}
}
}
if (chosen != null) {
return chosen;
}
throw new AmbiguousMethodCallException(exchange, possibles);
}
/**
* Creates an expression for the given parameter type if the parameter can
* be mapped automatically or null if the parameter cannot be mapped due to
* unsufficient annotations or not fitting with the default type
* conventions.
*/
protected Expression createParameterUnmarshalExpression(Class clazz, Method method, Class parameterType,
Annotation[] parameterAnnotation) {
// TODO look for a parameter annotation that converts into an expression
for (Annotation annotation : parameterAnnotation) {
Expression answer = createParameterUnmarshalExpressionForAnnotation(clazz, method, parameterType,
annotation);
if (answer != null) {
return answer;
}
}
return strategy.getDefaultParameterTypeExpression(parameterType);
}
protected boolean isPossibleBodyParameter(Annotation[] annotations) {
if (annotations != null) {
for (Annotation annotation : annotations) {
if ((annotation instanceof Property)
|| (annotation instanceof Header)
|| (annotation instanceof Headers)
|| (annotation instanceof OutHeaders)
|| (annotation instanceof Properties)) {
return false;
}
LanguageAnnotation languageAnnotation = annotation.annotationType().getAnnotation(LanguageAnnotation.class);
if (languageAnnotation != null) {
return false;
}
}
}
return true;
}
protected Expression createParameterUnmarshalExpressionForAnnotation(Class clazz, Method method,
Class parameterType,
Annotation annotation) {
if (annotation instanceof Property) {
Property propertyAnnotation = (Property)annotation;
return ExpressionBuilder.propertyExpression(propertyAnnotation.name());
} else if (annotation instanceof Properties) {
return ExpressionBuilder.propertiesExpression();
} else if (annotation instanceof Header) {
Header headerAnnotation = (Header)annotation;
return ExpressionBuilder.headerExpression(headerAnnotation.name());
} else if (annotation instanceof Headers) {
return ExpressionBuilder.headersExpression();
} else if (annotation instanceof OutHeaders) {
return ExpressionBuilder.outHeadersExpression();
} else {
LanguageAnnotation languageAnnotation = annotation.annotationType().getAnnotation(LanguageAnnotation.class);
if (languageAnnotation != null) {
Class<?> type = languageAnnotation.factory();
Object object = camelContext.getInjector().newInstance(type);
if (object instanceof AnnotationExpressionFactory) {
AnnotationExpressionFactory expressionFactory = (AnnotationExpressionFactory) object;
return expressionFactory.createExpression(camelContext, annotation, languageAnnotation, parameterType);
} else {
LOG.error("Ignoring bad annotation: " + languageAnnotation + "on method: " + method
+ " which declares a factory: " + type.getName()
+ " which does not implement " + AnnotationExpressionFactory.class.getName());
}
}
}
return null;
}
protected boolean isValidMethod(Class clazz, Method method) {
// must be a public method
if (!Modifier.isPublic(method.getModifiers())) {
return false;
}
// return type must not be an Exchange
if (method.getReturnType() != null && Exchange.class.isAssignableFrom(method.getReturnType())) {
return false;
}
return true;
}
public static ParameterMappingStrategy createParameterMappingStrategy(CamelContext camelContext) {
Registry registry = camelContext.getRegistry();
ParameterMappingStrategy answer = registry.lookup(ParameterMappingStrategy.class.getName(),
ParameterMappingStrategy.class);
if (answer == null) {
answer = new DefaultParameterMappingStrategy();
}
return answer;
}
}