openjpa/openjpa-examples/openbooks/web/query.jsp

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<%--
* 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.
--%>
<%-- ==================================================================== --%>
<%-- Executes a query which is determined by the request parameter. --%>
<%-- Displays the results --%>
<%-- ==================================================================== --%>
<%@include file="header.jsp"%>
<%@page import="openbook.server.OpenBookService"%>
<%@page import="openbook.domain.Book"%>
<%@page import="openbook.domain.Author"%>
<%@page import="openbook.util.JSPUtility"%>
<%@page import="java.util.List"%>
<div id="help">
<h3>Query Result</h3>
This page is displaying the result of the Criteria query specified in the previous Search page.
<ul>
<li><B>Readability</B>: Criteria query is more powerful than JPQL but hardly as readable.
JPA specification says nothing about how a Criteria Query should be displayed.
OpenJPA implementation provides a simple
<a HREF="generated-html/openbook/server/OpenBookServiceImpl.java.html#getQuery" type="popup">
<code>toString()</code></a> method to display a Criteria query as a string that is quite
<em>similar</em> to an equivalent JPQL string. <em>Similar</em> because Criteria query can
express certain queries that has no equivalent JPQL counterpart.
</li>
<li><B>Eager Fetching</B>: The query result displays the Author names as well, though the query
had only selected the Books. But the Authors have also been fetched because
many-to-many <a href="generated-html/openbook/domain/Book.java.html#authors" type="popup">
Book-Author relationship</a> is annotated to be <em>eagerly fetched</em>.
</li>
</ul>
</div>
<div id="content" style="width: 600px; display: block">
<%!
/**
* Concatenates the names of the given list of Authors.
*
*/
public static String namesOf(List<Author> authors) {
StringBuilder names = new StringBuilder();
if (authors == null)
return names.toString();
for (Author a : authors) {
if (names.length() != 0) names.append(", ");
names.append(a.getName());
}
return names.toString();
}
%>
<%
OpenBookService service = (OpenBookService)session.getAttribute(KEY_SERVICE);
if (service == null) {
%>
<jsp:forward page="<%= PAGE_HOME %>"></jsp:forward>
<%
}
%>
<%
String title = request.getParameter(FORM_TITLE);
Double minPrice = JSPUtility.toDouble(request.getParameter(FORM_PRICE_MIN));
Double maxPrice = JSPUtility.toDouble(request.getParameter(FORM_PRICE_MAX));
String author = request.getParameter(FORM_AUTHOR);
List<Book> books = service.select(title, minPrice, maxPrice, author);
String query = service.getQuery(title, minPrice, maxPrice, author);
%>
Query : <code><%= query %></code>
<p></p>
<%
if (books.isEmpty()) {
%>
did not select any book.
<p><A HREF="<%= PAGE_SEARCH %>">Search again</A></p>
<%
return;
}
%>
<br>
<table>
<caption>Selected <%= books.size() %> Book<%= books.size() == 1 ? "" : "s" %></caption>
<thead>
<tr>
<th width="08em">ISBN</th>
<th width="10em">Title</th>
<th width="06em">Price</th>
<th width="20em">Authors</th>
<th width="16em">Add to Cart</th>
</tr>
</thead>
<tfoot>
</tfoot>
<tbody>
<%
int i = 0;
for (Book book : books) {
session.setAttribute(book.getISBN(), book);
%>
<TR class="<%= i++%2 == 0 ? ROW_STYLE_EVEN : ROW_STYLE_ODD %>">
<TD> <%= book.getISBN() %> </TD>
<TD> <%= book.getTitle() %> </TD>
<TD> <%= JSPUtility.format(book.getPrice()) %> </TD>
<TD> <%= namesOf(book.getAuthors()) %> </TD>
<TD> <A HREF="<%= JSPUtility.encodeURL(PAGE_CART,
KEY_ACTION, ACTION_ADD, KEY_ISBN, book.getISBN()) %>">
<img src="images/add-to-cart.gif" width="106px" height="22px" border="0"></A></TD>
</TR>
<%
}
%>
</tbody>
</table>
<p>
</div>
<%@include file="footer.jsp"%>