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Procedure documentation Modifying the Search Page Locate the document in its SAP Library structure

Use

You must still make a few small changes to the third tutorial:

Layout

On the start page add statements to the layout for displaying error messages using the messages object:

<%@ page language="abap" %>

    <%@include file="head.htm" %>

<h3>Search</h3>

      <p>

Fill out one or more of the fields below to search for a book.

You can use the wildcard character '+' to replace just one letter and '*' to replace

any number of letters.

      <p>

<font color="red"><%= page->messages->assert_message( 'isbn' ) %></font>

<font color="red"><%= page->messages->assert_message( 'internal' ) %></font>

<font color="blue"><%= page->messages->assert_message( 'noresults' ) %></font>

  <form method="POST">

 <table>

       <tr><td width="180"> Author (last name) </td>

           <td> <input type="text" name="author" size="80"></td> </tr>

       <tr><td>Title </td>

           <td> <input type="text" name="title" size="80"></td></tr>

       <tr><td>Publisher </td>

           <td> <input type="text" name="publisher" size="40"></td></tr>

       <tr><td>Keyword </td>

           <td> <input type="text" name="keyword" size="20"</td></tr>

       <tr><td>ISBN </td>

           <td> <input type="text" name="isbn" size="13"></td></tr>

 </table>

     <p> <input type=submit name="onInputProcessing(search)"  value="Search for Book">

                 &nbsp;&nbsp;&nbsp;&nbsp;

                <input type="reset" value="Reset" name="B2">

   </form>

</body>

</html>

The following errors can occur at this point:

Note

In all error cases, the messages object outputs a message and the system navigates to the same page (this is set in the event handler OnInputProcessing), so that the customer can re-enter the data. The first two error messages are displayed in red font, the last error message is in blue.

Page Attributes

You need the additional page attribute isbn_tab for this tutorial. This is the table for the ISBNs with the reference type ISBN_TAB.

Event Handler OnInputProcessing

Create the search for using class CL_BOOK_SHOP (see also Data Models for the Bookshop Tutorialsas well as the following error cases in this event handler:

class CL_BOOK_SHOP definition load.

case event_id.

  when 'search'.

*look for matching books for user query

    CALL METHOD cl_book_shop=>search_book

      EXPORTING

        author = author

        title = title

        publisher = publisher

        ISBN = ISBN

        keyword = keyword

      IMPORTING

        isbn_tab = isbn_tab

      EXCEPTIONS

        no_search_parameter = 2

        invalid_isbn = 4.

 

* error handling

  if sy-subrc <> 0.

    case sy-subrc.

      when 4.

        page->messages->add_message(

        condition = 'isbn'

        message = 'You entered an invalid ISBN - please try again!'

          severity  = page->messages->CO_SEVERITY_ERROR ).

      when 2.

  when others.

        page->messages->add_message(

        condition = 'internal'

        message = 'An internal error occurred - please try again!'

          severity  = page->messages->CO_SEVERITY_FATAL_ERROR ).

endcase.

  else.

* no books found

*   if sy-subrc = 0.

      if isbn_tab is initial.

        page->messages->add_message(

         condition = 'noresults'

         message   = 'No books were found that match your query.'

         severity  = page->messages->CO_SEVERITY_INFO ).

* something found and no error

  else.

    navigation->next_page( 'TORESULTS' ).

  endif.

  endif.

 

    navigation->set_parameter( 'author' ).

    navigation->set_parameter( name = 'isbn_tab'

                               value = isbn_tab ).

 

  when others.

 

endcase.

Specify a message for each of the error cases stated in the layout.

If the internal return value sy-subrc does not equal 0, it can have values 2 or 4. Value 4 means that the ISBN that was entered is an incorrect ISBN and the messages object outputs a corresponding error message:

          page->messages->add_message(
          condition = 'isbn'
          message   = 'You entered an invalid ISBN - please try again!'
          severity  = page->messages->CO_SEVERITY_ERROR ).

add_message adds an individual message, below the specified condition (condition). This message or the message text itself is specified directly and not implemented as an OTR alias text. Parameter severity specifies the severity of the error: in this case it is a normal error (CO_SEVERITY_ERROR).

Note

You can find additional information about the use of message objects in the reference documentation in Using Object Messages and Class CL_BSP_MESSAGES.

Value 2 means that a serious internal error occured:

          page->messages->add_message(
          condition = 'internal'
          message   = 'An internal error occurred - please try again!'
          severity  = page->messages->CO_SEVERITY_FATAL_ERROR ).

 

If no results were found because of the user’s search query, internal value sy_subrc is set to 0 and the following message is displayed as information (this time not using the OTR):

        page->messages->add_message(
         condition = 'noresults'
         message   = 'No books were found that match your query.'
         severity  = page->messages->CO_SEVERITY_INFO ).

Only if no errors occur and the results are found for the search query is the results page displayed using navigation request TORESULTS.

This graphic is explained in the accompanying textNow modify the Title Bar on every page.

 

 

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