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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.rest.annotation;

import java.io.*;
import java.util.*;
import java.util.logging.*;

import javax.servlet.*;
import javax.servlet.http.*;

import org.apache.juneau.*;
import org.apache.juneau.config.*;
import org.apache.juneau.cp.Messages;
import org.apache.juneau.dto.swagger.*;
import org.apache.juneau.http.header.*;
import org.apache.juneau.http.exception.*;
import org.apache.juneau.rest.*;

/**
 * Identifies servlet and REST call lifecycle events which cause {@link RestHook @RestHook}-annotated Java methods
 * to be called.
 *
 * <ul class='seealso'>
 *    <li class='link'>{@doc RestLifecycleHooks}
 * </ul>
 */
public enum HookEvent {

   /**
    * Identifies a method that is called immediately after the <c>HttpServlet.service(HttpServletRequest, HttpServletResponse)</c>
    * method is called.
    *
    * <p>
    * Note that you only have access to the raw request and response objects at this point.
    *
    * <p>
    * The list of valid parameter types are as follows:
    * <ul>
    *    <li>Servlet request/response objects:
    *       <ul>
    *          <li>{@link HttpServletRequest}
    *          <li>{@link HttpServletResponse}
    *       </ul>
    * </ul>
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bcode w800'>
    *    <ja>@Rest</ja>(...)
    *    <jk>public class</jk> MyResource <jk>extends</jk> BasicRestServlet {
    *
    *       <jc>// Add a request attribute to all incoming requests.</jc>
    *       <ja>@RestHook</ja>(<jsf>START_CALL</jsf>)
    *       <jk>public void</jk> onStartCall(HttpServletRequest req) {
    *          req.setAttribute(<js>"foobar"</js>, <jk>new</jk> FooBar());
    *       }
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple START_CALL methods can be defined on a class.
    *       <br>START_CALL methods on parent classes are invoked before START_CALL methods on child classes.
    *       <br>The order of START_CALL method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception.
    *       <br>{@link HttpException HttpExceptions} can be thrown to cause a particular HTTP error status code.
    *       <br>All other exceptions cause an HTTP 500 error status code.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    * </ul>
    */
   START_CALL,

   /**
    * Identifies a method that gets called immediately before the <ja>@RestMethod</ja> annotated method gets called.
    *
    * <p>
    * At this point, the {@link RestRequest} object has been fully initialized, and all {@link RestGuard} and
    * {@link RestMatcher} objects have been called.
    *
    * <p>
    * The list of valid parameter types are as follows:
    * <ul>
    *    <li>Servlet request/response objects:
    *       <ul>
    *          <li>{@link HttpServletRequest}
    *          <li>{@link HttpServletResponse}
    *       </ul>
    *    <li>Extended request/response objects:
    *       <ul>
    *          <li>{@link RestRequest}
    *          <li>{@link RestResponse}
    *       </ul>
    *    <li>Header objects:
    *       <ul>
    *          <li>{@link Accept}
    *          <li>{@link AcceptCharset}
    *          <li>{@link AcceptEncoding}
    *          <li>{@link AcceptLanguage}
    *          <li>{@link Authorization}
    *          <li>{@link CacheControl}
    *          <li>{@link Connection}
    *          <li>{@link ContentLength}
    *          <li>{@link ContentType}
    *          <li>{@link org.apache.juneau.http.header.Date}
    *          <li>{@link Expect}
    *          <li>{@link From}
    *          <li>{@link Host}
    *          <li>{@link IfMatch}
    *          <li>{@link IfModifiedSince}
    *          <li>{@link IfNoneMatch}
    *          <li>{@link IfRange}
    *          <li>{@link IfUnmodifiedSince}
    *          <li>{@link MaxForwards}
    *          <li>{@link Pragma}
    *          <li>{@link ProxyAuthorization}
    *          <li>{@link Range}
    *          <li>{@link Referer}
    *          <li>{@link TE}
    *          <li>{@link UserAgent}
    *          <li>{@link Upgrade}
    *          <li>{@link Via}
    *          <li>{@link Warning}
    *          <li>{@link TimeZone}
    *       </ul>
    *    <li>Other objects:
    *       <ul>
    *          <li>{@link ResourceBundle}
    *          <li>{@link Messages}
    *          <li>{@link InputStream}
    *          <li>{@link ServletInputStream}
    *          <li>{@link Reader}
    *          <li>{@link OutputStream}
    *          <li>{@link ServletOutputStream}
    *          <li>{@link Writer}
    *          <li>{@link RequestHeaders}
    *          <li>{@link RequestQuery}
    *          <li>{@link RequestFormData}
    *          <li>{@link Logger}
    *          <li>{@link RestContext}
    *          <li>{@link org.apache.juneau.parser.Parser}
    *          <li>{@link Locale}
    *          <li>{@link Swagger}
    *          <li>{@link RequestPath}
    *          <li>{@link RequestBody}
    *          <li>{@link Config}
    *          <li>{@link UriContext}
    *          <li>{@link UriResolver}
    *       </ul>
    * </ul>
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bcode w800'>
    *    <ja>@Rest</ja>(...)
    *    <jk>public class</jk> MyResource <jk>extends</jk> BasicRestServlet {
    *
    *       <jc>// Log the incoming request.</jc>
    *       <ja>@RestHook</ja>(<jsf>PRE_CALL</jsf>)
    *       <jk>public void</jk> onPreCall(Accept accept, Logger logger) {
    *          logger.fine(<js>"Accept {0} header found."</js>, accept);
    *       }
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple PRE_CALL methods can be defined on a class.
    *       <br>PRE_CALL methods on parent classes are invoked before PRE_CALL methods on child classes.
    *       <br>The order of PRE_CALL method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception.
    *       <br>{@link HttpException HttpExceptions} can be thrown to cause a particular HTTP error status code.
    *       <br>All other exceptions cause an HTTP 500 error status code.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    *    <li>
    *       It's advisable not to mess around with the HTTP body itself since you may end up consuming the body
    *       before the actual REST method has a chance to use it.
    * </ul>
    */
   PRE_CALL,

   /**
    * Identifies a method that gets called immediately after the <ja>@RestMethod</ja> annotated method gets called.
    *
    * <p>
    * At this point, the output object returned by the method call has been set on the response, but
    * {@link RestConverter RestConverters} have not yet been executed and the response has not yet been written.
    *
    * <p>
    * The list of valid parameter types are the same as {@link #PRE_CALL}.
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bcode w800'>
    *    <ja>@Rest</ja>(...)
    *    <jk>public class</jk> MyResource <jk>extends</jk> BasicRestServlet {
    *
    *       <jc>// Log the result of the request.</jc>
    *       <ja>@RestHook</ja>(<jsf>POST_CALL</jsf>)
    *       <jk>public void</jk> onPostCall(RestResponse res, Logger logger) {
    *          logger.fine(<js>Output {0} was set on the response."</js>, res.getOutput());
    *       }
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple POST_CALL methods can be defined on a class.
    *       <br>POST_CALL methods on parent classes are invoked before POST_CALL methods on child classes.
    *       <br>The order of POST_CALL method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception, although at this point it is too late to set an HTTP error status code.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    * </ul>
    */
   POST_CALL,

   /**
    * Identifies a method that gets called right before we exit the servlet service method.
    *
    * <p>
    * At this point, the output has been written and flushed.
    *
    * <p>
    * The list of valid parameter types are as follows:
    * <ul>
    *    <li>Servlet request/response objects:
    *       <ul>
    *          <li>{@link HttpServletRequest}
    *          <li>{@link HttpServletResponse}
    *       </ul>
    * </ul>
    *
    * <p>
    * The following attributes are set on the {@link HttpServletRequest} object that can be useful for logging purposes:
    * <ul>
    *    <li><js>"Exception"</js> - Any exceptions thrown during the request.
    *    <li><js>"ExecTime"</js> - Execution time of the request.
    * </ul>
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bcode w800'>
    *    <ja>@Rest</ja>(...)
    *    <jk>public class</jk> MyResource <jk>extends</jk> BasicRestServlet {
    *
    *       <jc>// Log the time it took to execute the request.</jc>
    *       <ja>@RestHook</ja>(<jsf>END_CALL</jsf>)
    *       <jk>public void</jk> onEndCall(HttpServletRequest req, Logger logger) {
    *          Exception e = (Exception)req.getAttribute(<js>"Exception"</js>);
    *          Long execTime = (Long)req.getAttribute(<js>"ExecTime"</js>);
    *          <jk>if</jk> (e != <jk>null</jk>)
    *             logger.warn(e, <js>"Request failed in {0}ms."</js>, execTime);
    *          <jk>else</jk>
    *             logger.fine(<js>"Request finished in {0}ms."</js>, execTime);
    *       }
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple END_CALL methods can be defined on a class.
    *       <br>END_CALL methods on parent classes are invoked before END_CALL methods on child classes.
    *       <br>The order of END_CALL method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception, although at this point it is too late to set an HTTP error status code.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    * </ul>
    */
   END_CALL,

   /**
    * Identifies a method that gets called during servlet initialization.
    *
    * <p>
    * This method is called from within the {@link Servlet#init(ServletConfig)} method after the {@link RestContextBuilder}
    * object has been created and initialized with the annotations defined on the class, but before the
    * {@link RestContext} object has been created.
    *
    * <p>
    * The only valid parameter type for this method is {@link RestContextBuilder} which can be used to configure the servlet.
    *
    * <p>
    * An example of this is the <c>PetStoreResource</c> class that uses an init method to perform initialization
    * of an internal data structure.
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bcode w800'>
    *    <ja>@Rest</ja>(...)
    *    <jk>public class</jk> PetStoreResource <jk>extends</jk> ResourceJena {
    *
    *       <jc>// Our database.</jc>
    *       <jk>private</jk> Map&lt;Integer,Pet&gt; <jf>petDB</jf>;
    *
    *       <ja>@RestHook</ja>(<jsf>INIT</jsf>)
    *       <jk>public void</jk> onInit(RestContextBuilder builder) <jk>throws</jk> Exception {
    *          <jc>// Load our database from a local JSON file.</jc>
    *          <jf>petDB</jf> = JsonParser.<jsf>DEFAULT</jsf>.parse(getClass().getResourceAsStream(<js>"PetStore.json"</js>), LinkedHashMap.<jk>class</jk>, Integer.<jk>class</jk>, Pet.<jk>class</jk>);
    *       }
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple INIT methods can be defined on a class.
    *       <br>INIT methods on parent classes are invoked before INIT methods on child classes.
    *       <br>The order of INIT method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception causing initialization of the servlet to fail.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    * </ul>
    */
   INIT,

   /**
    * Identifies a method that gets called immediately after servlet initialization.
    *
    * <p>
    * This method is called from within the {@link Servlet#init(ServletConfig)} method after the {@link RestContext}
    * object has been created.
    *
    * <p>
    * The only valid parameter type for this method is {@link RestContext} which can be used to retrieve information
    * about the servlet.
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple POST_INIT methods can be defined on a class.
    *       <br>POST_INIT methods on parent classes are invoked before POST_INIT methods on child classes.
    *       <br>The order of POST_INIT method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception causing initialization of the servlet to fail.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    * </ul>
    */
   POST_INIT,

   /**
    * Identical to {@link #POST_INIT} except the order of execution is child-resources first.
    *
    * <p>
    * Use this annotation if you need to perform any kind of initialization on child resources before the parent resource.
    *
    * <p>
    * This method is called from within the {@link Servlet#init(ServletConfig)} method after the {@link RestContext}
    * object has been created and after the {@link #POST_INIT} methods have been called.
    *
    * <p>
    * The only valid parameter type for this method is {@link RestContext} which can be used to retrieve information
    * about the servlet.
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple POST_INIT_CHILD_FIRST methods can be defined on a class.
    *       <br>POST_INIT_CHILD_FIRST methods on parent classes are invoked before POST_INIT_CHILD_FIRST methods on child classes.
    *       <br>The order of POST_INIT_CHILD_FIRST method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       The method can throw any exception causing initialization of the servlet to fail.
    * </ul>
    */
   POST_INIT_CHILD_FIRST,

   /**
    * Identifies a method that gets called during servlet destroy.
    *
    * <p>
    * This method is called from within the {@link Servlet#destroy()}.
    *
    * <p>
    * The only valid parameter type for this method is {@link RestContext}, although typically no arguments will
    * be specified.
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bcode w800'>
    *    <ja>@Rest</ja>(...)
    *    <jk>public class</jk> PetStoreResource <jk>extends</jk> ResourceJena {
    *
    *       <jc>// Our database.</jc>
    *       <jk>private</jk> Map&lt;Integer,Pet&gt; <jf>petDB</jf>;
    *
    *       <ja>@RestHook</ja>(<jsf>DESTROY</jsf>)
    *       <jk>public void</jk> onDestroy() {
    *          <jf>petDB</jf> = <jk>null</jk>;
    *       }
    *    }
    * </p>
    *
    * <ul class='notes'>
    *    <li>
    *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
    *    <li>
    *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
    *    <li>
    *       Static methods can be used.
    *    <li>
    *       Multiple DESTROY methods can be defined on a class.
    *       <br>DESTROY methods on child classes are invoked before DESTROY methods on parent classes.
    *       <br>The order of DESTROY method invocations within a class is alphabetical, then by parameter count, then by parameter types.
    *    <li>
    *       In general, destroy methods should not throw any exceptions, although if any are thrown, the stack trace will be
    *       printed to <c>System.err</c>.
    *    <li>
    *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
    *       <br>The method is still considered part of the parent class for ordering purposes even though it's
    *       overridden by the child class.
    * </ul>
    */
   DESTROY
}