/*
* 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.felix.ipojo.handlers.lifecycle.controller;
import java.util.Dictionary;
import org.apache.felix.ipojo.ComponentInstance;
import org.apache.felix.ipojo.ConfigurationException;
import org.apache.felix.ipojo.InstanceManager;
import org.apache.felix.ipojo.PrimitiveHandler;
import org.apache.felix.ipojo.architecture.ComponentTypeDescription;
import org.apache.felix.ipojo.metadata.Element;
import org.apache.felix.ipojo.parser.FieldMetadata;
import org.apache.felix.ipojo.parser.PojoMetadata;
/**
* Lifecycle Controller handler.
* This handler allow a POJO to vote for the instance state. By setting a boolean field to true or false, the handler state changed.
* @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
*/
public class ControllerHandler extends PrimitiveHandler {
/**
* Actual handler (i.e. field value) state
*/
private boolean m_state;
/**
* The controller field name.
*/
private String m_field;
/**
* Configure method.
* Look for the first 'controller' element.
* @param metadata : metadata
* @param configuration : configuration
* @throws ConfigurationException : the field attribute is missing or does not exist in the class.
* @see org.apache.felix.ipojo.Handler#configure(org.apache.felix.ipojo.InstanceManager, org.apache.felix.ipojo.metadata.Element, java.util.Dictionary)
*/
public void configure(Element metadata, Dictionary configuration) throws ConfigurationException {
Element[] controller = metadata.getElements("controller");
m_field = controller[0].getAttribute("field");
getInstanceManager().register(new FieldMetadata(m_field, "boolean"), this);
}
/**
* Start method.
* This methods initializes the controller value.
* @see org.apache.felix.ipojo.Handler#start()
*/
public void start() {
// On start we should ask for the value
Object o = getInstanceManager().getFieldValue(m_field);
if (o == null || ! (o instanceof Boolean)) {
m_state = true;
} else {
m_state = ((Boolean) o).booleanValue();
}
if ( ! m_state) {
setValidity(false);
}
}
/**
* Stop method.
* Nothing to do.
* @see org.apache.felix.ipojo.Handler#stop()
*/
public void stop() {
// Nothing to do.
}
/**
* GetterCallback.
* @param pojo : the pojo object on which the field is accessed
* Return the stored value.
* @param field : field name.
* @param value : value given by the previous handler.
* @return : the handler state.
*/
public Object onGet(Object pojo, String field, Object value) {
if (m_state) {
return Boolean.TRUE;
} else {
return Boolean.FALSE;
}
}
/**
* SetterCallback.
* @param pojo : the pojo object on which the field is accessed
* Store the new field value & invalidate / validate the handler is required.
* @param field : field name.
* @param value : new value.
*/
public void onSet(Object pojo, String field, Object value) {
if (value instanceof Boolean) {
boolean newValue = ((Boolean) value).booleanValue();
if (newValue != m_state) {
m_state = newValue;
if (m_state) {
((InstanceManager) getHandlerManager()).setState(ComponentInstance.VALID);
setValidity(true);
} else {
((InstanceManager) getHandlerManager()).setState(ComponentInstance.INVALID);
setValidity(false);
}
}
} else {
error("Boolean expected for the lifecycle controller");
getInstanceManager().stop();
}
}
/**
* Initialize the component factory.
* The controller field is checked to avoid configure check.
* @param desc : component description
* @param metadata : component type metadata
* @throws ConfigurationException : occurs if the controller field is not in the POJO class or is not a boolean.
* @see org.apache.felix.ipojo.Handler#initializeComponentFactory(org.apache.felix.ipojo.architecture.ComponentTypeDescription, org.apache.felix.ipojo.metadata.Element)
*/
public void initializeComponentFactory(ComponentTypeDescription desc, Element metadata) throws ConfigurationException {
String field = null;
Element[] controller = metadata.getElements("controller");
// Use only the first controller
field = controller[0].getAttribute("field");
if (field == null) {
throw new ConfigurationException("Lifecycle controller : the controller element needs to contain a field attribute");
}
PojoMetadata method = getFactory().getPojoMetadata();
FieldMetadata fieldMetadata = method.getField(field);
if (fieldMetadata == null) {
throw new ConfigurationException("Lifecycle controller : The field " + field + " does not exist in the implementation class");
}
if (!fieldMetadata.getFieldType().equalsIgnoreCase("boolean")) {
throw new ConfigurationException("Lifecycle controller : The field " + field + " must be a boolean (" + fieldMetadata.getFieldType() + " found)");
}
}
}