/*
 * 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 javax.jbi.component;

import java.util.MissingResourceException;
import java.util.logging.Logger;

import javax.jbi.JBIException;
import javax.jbi.messaging.DeliveryChannel;
import javax.jbi.messaging.MessagingException;
import javax.jbi.servicedesc.ServiceEndpoint;

import javax.xml.namespace.QName;

import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;

/**
 * This interface provides access to data needed by a JBI component
 * about the JBI environment in which it is installed, as well providing
 * the means to allow the component to inform the JBI environment about
 * services provided by this component. This interface provides methods
 * for the following functions:
 * <ul>
 *   <li>Get the <bold>DeliveryChannel</bold> for this component. This is
 *       required to allow the component to send and receive message
 *       exchanges.</li>
 *   <li><bold>Activate</bold> (and deactivate) service endpoints provided
 *       by this component.</li>
 *   <li><bold>Register</bold> (and deregister) external endpoints provided
 *       by this component.</li>
 *   <li><bold>Query</bold> available endpoints (internal and external).</li>
 *   <li><bold>Query</bold> various data about the component, as installed
 *       in the JBI environment (name, workspace root, install root, initial
 *       JNDI context, MBean Server, Transaction Manager).</li>
 *   <li><bold>Loggers</bold>. Obtain the component's logger and subloggers.</li>
 *   <li><bold>MBean name creator</bold>. Access a utility for creating
 *       custom MBean names.</li>
 *   <li><bold>EPR Resolver</bold>. Ask JBI to resolve an endpoint reference
 *       (EPR), converting it into a service endpoint.</li>
 *
 * Note: The term "NMR" (meaning Normalized Message Router) is used here to refer
 * to the messaging system of the JBI implementation. This term is used as a
 * synonym for the JBI implementation, and refers only to the logical message
 * routing functions of a JBI implementation. It is not meant to require that
 * JBI implementations literally have a subsystem named "NMR".
 *
 * @author JSR208 Expert Group
 */
public interface ComponentContext {

    /**
     * Activates the named endpoint with the NMR. Activation indicates to the NMR
     * that this component is ready to process requests sent to the named endpoint.
     *
     * Note that the JBI implementation may call this component's
     * {@link Component#getServiceDescription(ServiceEndpoint)} method before returning
     * from this method call; the component's implementation must be ready to supply
     * service description metadata before the result of this activation call (a
     * ServiceEndpoint) is known.
     *
     * @param serviceName qualified name of the service the endpoint exposes; must
     *                    be non-null.
     * @param endpointName the name of the endpoint to be activated; must be non-null
     *                     and non-empty.
     * @return a reference to the activated endpoint; must be non-null.
     * @throws JBIException if the endpoint cannot be activated.
     */
    ServiceEndpoint activateEndpoint(QName serviceName, String endpointName) throws JBIException;


    /**
     * Deactivates the given endpoint with the NMR. Deactivation indicates to the NMR
     * that this component will no longer process requests sent to the named endpoint.
     *
     * @param endpoint reference to the endpoint to be deactivated; must be non-null.
     * @throws JBIException if the endpoint cannot be deactivated.
     */
    void deactivateEndpoint(ServiceEndpoint endpoint) throws JBIException;

    /**
     * Registers the given external endpoint with the NMR. This indicates to the NMR that
     * the given endpoint is used as a proxy for external service consumers to access an
     * internal service of the same service name (but a different endpoint name).
     *
     * @param externalEndpoint the external endpoint to be registered, must be non-null.
     * @throws JBIException if an external endpoint with the same name is already registered,
     *                      by this or another component.
     */
    void registerExternalEndpoint(ServiceEndpoint externalEndpoint) throws JBIException;

    /**
     * Deregisters the given external endpoint with the NMR. This indicates to the NMR that
     * the given external endpoint can no longer be used as a proxy for external service
     * consumers to access an internal service of the same service name.
     *
     * @param externalEndpoint the external endpoint to be deregistered; must be non-null.
     * @throws JBIException if the given external endpoint was not previously registered.
     */
    void deregisterExternalEndpoint(ServiceEndpoint externalEndpoint) throws JBIException;

    /**
     * Resolve the given endpoint reference into a service endpoint. This is called by the
     * component when it has an EPR that it wants to resolve into a service endpoint.
     *
     * Note that the service endpoint returned refers to a dynamic endpoint; the endpoint
     * will exist only as long as this component retains a strong reference to the object
     * returned by this method. The endpoint may not be included in the list of "activated"
     * endpoints.
     *
     * @param epr endpoint reference as an XML fragment; must be non-null.
     * @return the service endpoint corresponding to the given endpoint reference; null if
     *         the reference cannot be resolved.
     */
    ServiceEndpoint resolveEndpointReference(DocumentFragment epr);

    /**
     * Get the unique component name of this component, ass assigned by the identification
     * section of this component's installation descriptor.
     *
     * @return the component name; must be non-null and non-empty.
     */
    String getComponentName();

    /**
     * Get a channel for this component to use to communicate with the Normalized Message
     * Router. This channel must be used by the component to send and receive message
     * exchanges.
     *
     * @return the delivery channel for this component; must be non-null.
     * @throws MessagingException if a channel has already been opened, but not yet closed.
     */
    DeliveryChannel getDeliveryChannel() throws MessagingException;

    /**
     * Get the service endpoint for the named activated endpoint, if any.
     *
     * @param service qualified-name of the endpoint's service; must be non-null.
     * @param name name of the endpoint; must be non-null.
     * @return the named endpoint, or null if the named endpoint is not activated.
     */
    ServiceEndpoint getEndpoint(QName service, String name);

    /**
     * Retrieve the service description metadata for the specified endpoint.
     *
     * Note that the result can use either the WSDL 1.1 or WSDL 2.0 description language.
     *
     * @param endpoint endpoint reference; must be non-null.
     * @return metadata describing endpoint, or null if metadata is unavailable.
     * @throws JBIException invalid endpoint reference.
     */
    Document getEndpointDescriptor(ServiceEndpoint endpoint) throws JBIException;

    /**
     * Queries the NMR for active endpoints that implement the given interface. This
     * will return the endpoints for all services and endpoints that implement the
     * named interface (portType in WSDL 1.1). This method does NOT include external
     * endpoints (those registered using {@link #registerExternalEndpoint(ServiceEndpoint)}).
     *
     * @param interfaceName qualified name of interface/portType that is implemented
     *                      by the endpoint; if null then all activated endpoints in
     *                      the JBI environment must be returned.
     * @return an array of available endpoints for the specified interface name; must
     *         be non-null; may be empty.
     */
    ServiceEndpoint[] getEndpoints(QName interfaceName);

    /**
     * Queries the NMR for active endpoints belonging to the given service. This
     * method does NOT include external endpoints (those registered using
     * {@link #registerExternalEndpoint(ServiceEndpoint)}).
     *
     * @param serviceName qualified name of the service that the endpoints are part
     *                    of; must be non-null.
     * @return an array of available endpoints for the specified service name; must
     *         be non-null; may be empty.
     */
    ServiceEndpoint[] getEndpointsForService(QName serviceName);

    /**
     * Queries the NMR for external endpoints that implement the given interface name.
     * This methods returns only registered external endpoints (see
     * {@link #registerExternalEndpoint(ServiceEndpoint)}).
     *
     * @param interfaceName qualified name of interface implemented by the endpoints;
     *                      must be non-null.
     * @return an array of available external endpoints for the specified interface name;
     *         must be non-null; may be empty.
     */
    ServiceEndpoint[] getExternalEndpoints(QName interfaceName);

    /**
     * Queries the NMR for external endpoints that are part of the given service.
     *
     * @param serviceName qualified name of service that contains the endpoints;
     *                    must be non-null.
     * @return an array of available external endpoints for the specified service name;
     *         must be non-null; may be empty.
     */
    ServiceEndpoint[] getExternalEndpointsForService(QName serviceName);

    /**
     * Get the installation root directory path for this component.
     *
     * This method MUST return the file path formatted for the underlying platform.
     *
     * @return the installation root directory path, in platform-specific form;
     *         must be non-null and non-empty.
     */
    String getInstallRoot();

    /**
     * Get a logger instance from JBI. Loggers supplied by JBI are guaranteed to have
     * unique names such that they avoid name collisions with loggers from other
     * components created using this method. The suffix parameter allows for the
     * creation of subloggers as needed. The JBI specification says nothing about
     * the exact names to be used, only that they must be unique across components
     * and the JBI implementation itself.
     *
     * @param suffix for creating subloggers; use an empty string for the base component
     *               logger; must be non-null.
     * @param resourceBundleName name of ResourceBundle to be used for localizing messages
     *                           for the logger. May be null if none of the messages require
     *                           localization. The resource, if non-null, must be loadable
     *                           using the component's class loader as the initiating loader.
     * @return a standard logger, named uniquely for this component (plus the given suffix,
     *         if applicable); must be non-null.
     * @throws java.util.MissingResourceException if the ResourceBundleName is non-null and no
     *                                            corresponding resource can be found.
     * @throws JBIException if the resourceBundleName has changed from a previous invocation
     *                      by this component of this method with the same suffix.
     */
    Logger getLogger(String suffix, String resourceBundleName) throws MissingResourceException, JBIException;

    /**
     * Get a reference to the MBeanNames creator for use in creating custom MBean names.
     *
     * @return reference to the MBeanNames creator; must be non-null.
     */
    javax.jbi.management.MBeanNames getMBeanNames();

    /**
     * Get the JMX MBean server used to register all MBeans in the JBI environment.
     *
     * @return a reference to the MBean server; must be non-null.
     */
    javax.management.MBeanServer getMBeanServer();

    /**
     * Get the JNDI naming context for this component. This context is a standard JNDI
     * InitialContext but its content will vary based on the environment in which the JBI
     * implementation is running.
     * 
     * @return the JNDI naming context; must be non-null.
     */
    javax.naming.InitialContext getNamingContext();

    /**
     * Get the TransactionManager for this implementation. The instance returned is an
     * implementation of the standard JTA interface. If none is available, this method
     * returns null.
     *
     * The object returned by this method is untyped, to allow this interface to be compiled
     * in environments that do not support JTA. If not null, the object returned must be of
     * type javax.transaction.TransactionManager.
     *
     * This downcast is necessary because JBI is used in environments that do not support
     * JTA (i.e., J2SE). Explicit use of JTA types would cause compilation failures in
     * such environments.
     *
     * @return A TransactionManager instance, or null if none is available in the
     *         execution environment.
     */
    Object getTransactionManager();

    /**
     * Get the root directory path for this component's private workspace.
     *
     * This method MUST return the file path formatted for the underlying platform.
     *
     * The returned value must indicate a valid file path that the component may use
     * to write files to, and read files from.
     *
     * @return the private workspace root path, in platform-specific form;
     *         must be non-null and non-empty.
     */
    String getWorkspaceRoot();

}