This demo allows you to edit a table of data
Person | Age | Superhero? | Actions |
---|
Name: | |
Address: | |
Age: | |
Superhero?: | |
(ID=-1) |
When the page first loads, the onload event calls the server-side
People.getSmallCrowd()
function to return an array of people
objects.
A Person is just a POJO containing an id, name and address fields along an age as an integer an boolean superhero status. Full details of the Java source are shown on the "Source" tab.
The Javascript uses the cloneNode()
feature to create a row
in a table for each returned person. So for each person we do this:
dwr.util.cloneNode("pattern", { idSuffix:person.id });
This creates a copy of the node with the id "pattern", and alters the ids of any sub-nodes to have a suffix of the current persons id, so if pattern looks like this:
<div id="pattern"><input id="edit"/></div>
Then after cloning using an idSuffix:42, you will have this:
<div id="pattern"><input id="edit"/></div> <div id="pattern42"><input id="edit42"/></div>
After cloning we then fill in the blanks in the newly cloned row. This
uses the setValue
that we looked at in the Dynamic Text demo:
dwr.util.setValue("tableName" + id, person.name); dwr.util.setValue("tableSalary" + id, person.salary); dwr.util.setValue("tableAddress" + id, person.address);
We also need to ensure that the pattern row is not visible, but the clones are. We do this by setting a style of display:none on the pattern row in the HTML, and then setting the cloned row to have display:table-row in the Javascript:
$("pattern" + id).style.display = "table-row";
We need to account for the fact that this could be a re-draw rather than
a draw on page-load, so we might need to remove old rows.
dwr.util.removeAllRows()
as been around since 1.0, but new in
2.0 is the options object which can contain a filter to be selective about
the rows we remove. In this case we want to remove everything but the
"pattern" row.
// Delete all the rows except for the "pattern" row dwr.util.removeAllRows("peoplebody", { filter:function(tr) { return (tr.id != "pattern"); }});
For the full Javascript or the HTML, see the source tab. The full Javascript does 2 extra things - it caches the people, and sorts them.
When an 'edit' button is clicked, the editClicked()
function
is called with the id of the button. We can work out the person id from this
easily because the button was created by the clone process, so the person id
is just the button id without the 'edit' prefix.
This makes the editClicked()
function really simple:
function editClicked(eleid) { // we were an id of the form "edit{id}", eg "edit42". We lookup the "42" var person = peopleCache[eleid.substring(4)]; dwr.util.setValues(person); }
The dwr.util.setValues()
function finds form fields with the
same names as the properties of the object passed in.
There is a good use of dwr.util.getValues()
in the code to
post changes back to the server:
function writePerson() { var person = { id:viewed, name:null, address:null, age:null, superhero:null }; dwr.util.getValues(person); dwr.engine.beginBatch(); People.setPerson(person); fillTable(); dwr.engine.endBatch(); }
First we create an object which is filled out by
dwr.util.getValues()
. We then post the change to the server, and
update the table. We use a batch for the last 2 operations to ensure that we
only make a single round-trip to the server.
See the source tab for full source.
<h3>All People</h3> <table border="1" class="rowed grey"> <thead> <tr> <th>Person</th> <th>Age</th> <th>Superhero?</th> <th>Actions</th> </tr> </thead> <tbody id="peoplebody"> <tr id="pattern" style="display:none;"> <td> <span id="tableName">Name</span><br/> <small> <span id="tableAddress">Address</span></small> </td> <td><span id="tableAge">Age</span></td> <td><span id="tableSuperhero">Superhero</span></td> <td> <input id="edit" type="button" value="Edit" onclick="editClicked(this.id)"/> <input id="delete" type="button" value="Delete" onclick="deleteClicked(this.id)"/> </td> </tr> </tbody> </table> <h3>Edit Person</h3> <table class="plain"> <tr> <td>Name:</td> <td><input id="name" type="text" size="30"/></td> </tr> <tr> <td>Address:</td> <td><input id="address" type="text" size="40"/></td> </tr> <tr> <td>Age:</td> <td><input id="age" type="text" size="20"/></td> </tr> <tr> <td>Superhero?:</td> <td><input id="superhero" type="checkbox" size="20"/></td> </tr> <tr> <td colspan="2" align="right"> <small>(ID=<span id="id">-1</span>)</small> <input type="button" value="Save" onclick="writePerson()"/> <input type="button" value="Clear" onclick="clearPerson()"/> </td> </tr> </table>
function init() { dwr.util.useLoadingMessage(); fillTable(); } var peopleCache = { }; var viewed = -1; function fillTable() { People.getSmallCrowd(function(people) { // Delete all the rows except for the "pattern" row dwr.util.removeAllRows("peoplebody", { filter:function(tr) { return (tr.id != "pattern"); }}); // Create a new set cloned from the pattern row var person, id; people.sort(function(p1, p2) { return p1.name.localeCompare(p2.name); }); for (var i = 0; i < people.length; i++) { person = people[i]; id = person.id; dwr.util.cloneNode("pattern", { idSuffix:id }); dwr.util.setValue("tableName" + id, person.name); dwr.util.setValue("tableAge" + id, person.age); dwr.util.setValue("tableAddress" + id, person.address); dwr.util.setValue("tableSuperhero" + id, person.superhero ? "Yes" : "No"); dwr.util.byId("pattern" + id).style.display = ""; // officially we should use table-row, but IE prefers "" for some reason peopleCache[id] = person; } }); } function editClicked(eleid) { // we were an id of the form "edit{id}", eg "edit42". We lookup the "42" var person = peopleCache[eleid.substring(4)]; dwr.util.setValues(person); } function deleteClicked(eleid) { // we were an id of the form "delete{id}", eg "delete42". We lookup the "42" var person = peopleCache[eleid.substring(6)]; if (confirm("Are you sure you want to delete " + person.name + "?")) { dwr.engine.beginBatch(); People.deletePerson(person.id); fillTable(); dwr.engine.endBatch(); } } function writePerson() { var person = { id:viewed, name:null, address:null, age:null, superhero:null }; dwr.util.getValues(person); dwr.engine.beginBatch(); People.setPerson(person); fillTable(); dwr.engine.endBatch(); } function clearPerson() { viewed = -1; dwr.util.setValues({ id:-1, name:null, address:null, salary:null }); }
public class People { public People() { smallCrowd = createCrowd(10); } public Collection<Person> getSmallCrowd() { return smallCrowd.values(); } public String setPerson(Person person) { smallCrowd.put(person.getId(), person); return "Updated values for " + person.getName(); } public String deletePerson(String id) { Person person = smallCrowd.remove(id); if (person == null) { return "Person does not exist"; } else { return "Deleted " + person.getName(); } } private final Map<String, Person> smallCrowd; // ... }
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://getahead.org/dwr/dwr20.dtd"> <dwr> <allow> <create creator="new" javascript="People" scope="script"> <param name="class" value="org.getahead.dwrdemo.people.People"/> </create> <convert match="org.getahead.dwrdemo.people.Person" converter="bean"/> </allow> </dwr>