/*
 * 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.
 */

#ifndef AXIS2_HANDLER_H
#define AXIS2_HANDLER_H

/**
 * @defgroup axis2_handler handler
 * @ingroup axis2_handler
 * handler is the smallest unit of execution in the Axis2 engine's execution flow.
 * The engine could have two flows, the in-flow and out-flow. A flow is a
 * collection of phases and a phase in turn is a collection of handlers.
 * handlers are configured in relation to modules. A module is a point of
 * extension in the Axis2 engine and a module would have one or more handlers
 * defined in its configuration. The module configuration defines the phases
 * each handler is attached to. A handler is invoked when the phase within which
 * it lives is invoked. handler is stateless and it is using the message context
 * that the state information is captures across invocations.
 * @{
 */

/**
 * @file axis2_handler.h
 */

#include <axis2_defines.h>
#include <axutil_qname.h>
#include <axutil_param.h>

#ifdef __cplusplus
extern "C"
{
#endif

    /** Type name for struct axis2_handler */
    typedef struct axis2_handler axis2_handler_t;

    struct axis2_handler_desc;
    struct axis2_msg_ctx;

    typedef axis2_status_t(
        AXIS2_CALL
        * AXIS2_HANDLER_INVOKE) (
            axis2_handler_t * handler,
            const axutil_env_t * env,
            struct axis2_msg_ctx * msg_ctx);

    /**
     * Free handler struct.
     * @param handler pointer to handler
     * @param env pointer to environment struct
     * @return AXIS2_SUCCESS on success, else AXIS2_FAILURE
     */
    AXIS2_EXTERN void AXIS2_CALL
    axis2_handler_free(
        axis2_handler_t * handler,
        const axutil_env_t * env);

    /**
     * Initializes the handler with the information form handler description.
     * @param handler pointer to handler
     * @param env pointer to environment struct
     * @param handler_desc pointer to handler description related to the handler
     * @return AXIS2_SUCCESS on success, else AXIS2_FAILURE
     */
    AXIS2_EXTERN axis2_status_t AXIS2_CALL
    axis2_handler_init(
        axis2_handler_t * handler,
        const axutil_env_t * env,
        struct axis2_handler_desc *handler_desc);

    /**
     * Invoke is called to do the actual work assigned to the handler.
     * The phase that owns the handler is responsible for calling invoke
     * on top of the handler. Those structs that implement the interface 
     * of the handler should implement the logic for invoke and assign the
     * respective function pointer to invoke operation of the ops struct.
     * @param handler pointer to handler
     * @param env pointer to environment struct
     * @param msg_ctx pointer to message context
     * @return AXIS2_SUCCESS on success, else AXIS2_FAILURE
     */
    AXIS2_EXTERN axis2_status_t AXIS2_CALL
    axis2_handler_invoke(
        axis2_handler_t * handler,
        const axutil_env_t * env,
        struct axis2_msg_ctx *msg_ctx);

    /**
     * Gets QName.
     * @param handler pointer to handler
     * @param env pointer to environment struct
     * @return pointer to QName of the handler
     */
    AXIS2_EXTERN const axutil_string_t *AXIS2_CALL
    axis2_handler_get_name(
        const axis2_handler_t * handler,
        const axutil_env_t * env);

    /**
     * Gets the named parameter.
     * @param handler pointer to handler
     * @param env pointer to environment struct
     * @param name name of the parameter to be accessed
     */
    AXIS2_EXTERN axutil_param_t *AXIS2_CALL
    axis2_handler_get_param(
        const axis2_handler_t * handler,
        const axutil_env_t * env,
        const axis2_char_t * name);

    /**
      * Gets the handler description related to the handler.
      * @param handler pointer to handler
      * @param env pointer to environment struct
      * @return pointer to handler description struct related to handler    
      */
    AXIS2_EXTERN struct axis2_handler_desc *AXIS2_CALL

                axis2_handler_get_handler_desc(
                    const axis2_handler_t * handler,
                    const axutil_env_t * env);

    AXIS2_EXTERN axis2_status_t AXIS2_CALL
    axis2_handler_set_invoke(
        axis2_handler_t * handler,
        const axutil_env_t * env,
        AXIS2_HANDLER_INVOKE func);

    /**
     * Function pointer defining the creates syntax for a handler struct instance.
     * @param env pointer to environment struct
     * @param pointer to qname
     * @return pointer to newly created handler struct
     */
    typedef axis2_handler_t *(
        AXIS2_CALL
        * AXIS2_HANDLER_CREATE_FUNC)(
            const axutil_env_t * env,
            const axutil_string_t * name);

    /**
     * Creates handler struct instance.
     * @param env pointer to environment struct
     * @return pointer to newly created handler struct
     */
    AXIS2_EXTERN axis2_handler_t *AXIS2_CALL
    axis2_handler_create(
        const axutil_env_t * env);

    /**
     * Creates a handler with invoke method implemented to fill in the service 
     * and operation context information.
     * @param env pointer to environment struct
     * @param qname pointer to qname, this is cloned within create method
     * @return pointer to newly created handler struct
     */
    AXIS2_EXTERN axis2_handler_t *AXIS2_CALL
    axis2_ctx_handler_create(
        const axutil_env_t * env,
        const axutil_string_t * qname);

    /** @} */

#ifdef __cplusplus
}
#endif

#endif                          /* AXIS2_HANDLER_H */