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The Core Camel Java DSL based router
/**
* 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.model.language;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
import org.apache.camel.CamelContext;
import org.apache.camel.Expression;
import org.apache.camel.ExpressionIllegalSyntaxException;
import org.apache.camel.Predicate;
import org.apache.camel.component.bean.BeanHolder;
import org.apache.camel.component.bean.BeanInfo;
import org.apache.camel.component.bean.ConstantBeanHolder;
import org.apache.camel.component.bean.ConstantStaticTypeBeanHolder;
import org.apache.camel.component.bean.MethodNotFoundException;
import org.apache.camel.component.bean.RegistryBean;
import org.apache.camel.language.bean.BeanExpression;
import org.apache.camel.spi.Metadata;
import org.apache.camel.util.ObjectHelper;
import org.apache.camel.util.OgnlHelper;
/**
* For expressions and predicates using a java bean (aka method call)
*
* @version
*/
@Metadata(firstVersion = "1.3.0", label = "language,core,java", title = "Bean method")
@XmlRootElement(name = "method")
@XmlAccessorType(XmlAccessType.FIELD)
public class MethodCallExpression extends ExpressionDefinition {
@XmlAttribute
@Deprecated
private String bean;
@XmlAttribute
private String ref;
@XmlAttribute
private String method;
@XmlAttribute(name = "beanType")
private String beanTypeName;
@XmlTransient
private Class beanType;
@XmlTransient
private Object instance;
public MethodCallExpression() {
}
public MethodCallExpression(String beanName) {
this(beanName, null);
}
public MethodCallExpression(String beanName, String method) {
super(beanName);
this.method = method;
}
public MethodCallExpression(Object instance) {
this(instance, null);
}
public MethodCallExpression(Object instance, String method) {
super(ObjectHelper.className(instance));
// must use setter as they have special logic
setInstance(instance);
setMethod(method);
}
public MethodCallExpression(Class type) {
this(type, null);
}
public MethodCallExpression(Class type, String method) {
super(type.getName());
this.beanType = type;
this.method = method;
}
public String getLanguage() {
return "bean";
}
public String getBean() {
return bean;
}
/**
* Either a reference or a class name of the bean to use
*/
public void setBean(String bean) {
this.bean = bean;
}
public String getRef() {
return ref;
}
/**
* Reference to bean to lookup in the registry
*/
public void setRef(String ref) {
this.ref = ref;
}
public String getMethod() {
return method;
}
/**
* Name of method to call
*/
public void setMethod(String method) {
this.method = method;
}
public Class getBeanType() {
return beanType;
}
public void setBeanType(Class beanType) {
this.beanType = beanType;
this.instance = null;
}
public String getBeanTypeName() {
return beanTypeName;
}
/**
* Class name of the bean to use
*/
public void setBeanTypeName(String beanTypeName) {
this.beanTypeName = beanTypeName;
}
public Object getInstance() {
return instance;
}
public void setInstance(Object instance) {
// people may by mistake pass in a class type as the instance
if (instance instanceof Class) {
this.beanType = (Class) instance;
this.instance = null;
} else {
this.beanType = null;
this.instance = instance;
}
}
@Override
public Expression createExpression(CamelContext camelContext) {
Expression answer;
if (beanType == null && beanTypeName != null) {
try {
beanType = camelContext.getClassResolver().resolveMandatoryClass(beanTypeName);
} catch (ClassNotFoundException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
}
}
BeanHolder holder;
if (beanType != null) {
// create a bean if there is a default public no-arg constructor
if (ObjectHelper.hasDefaultPublicNoArgConstructor(beanType)) {
instance = camelContext.getInjector().newInstance(beanType);
holder = new ConstantBeanHolder(instance, camelContext);
} else {
holder = new ConstantStaticTypeBeanHolder(beanType, camelContext);
}
} else if (instance != null) {
holder = new ConstantBeanHolder(instance, camelContext);
} else {
String ref = beanName();
// if its a ref then check that the ref exists
BeanHolder regHolder = new RegistryBean(camelContext, ref);
// get the bean which will check that it exists
instance = regHolder.getBean();
holder = new ConstantBeanHolder(instance, camelContext);
}
// create answer using the holder
answer = new BeanExpression(holder, getMethod());
// and do sanity check that if a method name was given, that it exists
validateHasMethod(camelContext, instance, beanType, getMethod());
return answer;
}
@Override
public Predicate createPredicate(CamelContext camelContext) {
return (BeanExpression) createExpression(camelContext);
}
/**
* Validates the given bean has the method.
*
* This implementation will skip trying to validate OGNL method name expressions.
*
* @param context camel context
* @param bean the bean instance
* @param type the bean type
* @param method the method, can be null if no method name provided
* @throws org.apache.camel.RuntimeCamelException is thrown if bean does not have the method
*/
protected void validateHasMethod(CamelContext context, Object bean, Class type, String method) {
if (method == null) {
return;
}
if (bean == null && type == null) {
throw new IllegalArgumentException("Either bean or type should be provided on " + this);
}
// do not try to validate ognl methods
if (OgnlHelper.isValidOgnlExpression(method)) {
return;
}
// if invalid OGNL then fail
if (OgnlHelper.isInvalidValidOgnlExpression(method)) {
ExpressionIllegalSyntaxException cause = new ExpressionIllegalSyntaxException(method);
throw ObjectHelper.wrapRuntimeCamelException(new MethodNotFoundException(bean != null ? bean : type, method, cause));
}
if (bean != null) {
BeanInfo info = new BeanInfo(context, bean.getClass());
if (!info.hasMethod(method)) {
throw ObjectHelper.wrapRuntimeCamelException(new MethodNotFoundException(null, bean, method));
}
} else {
BeanInfo info = new BeanInfo(context, type);
// must be a static method as we do not have a bean instance to invoke
if (!info.hasStaticMethod(method)) {
throw ObjectHelper.wrapRuntimeCamelException(new MethodNotFoundException(null, type, method, true));
}
}
}
protected String beanName() {
if (bean != null) {
return bean;
} else if (ref != null) {
return ref;
} else if (instance != null) {
return ObjectHelper.className(instance);
}
return getExpression();
}
@Override
public String toString() {
boolean isRef = bean != null || ref != null;
return "bean[" + (isRef ? "ref:" : "") + beanName() + (method != null ? " method:" + method : "") + "]";
}
}