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In the previous chapters, we saw how Tapestry can handle simple links, even links that pass information in the URL. In this chapter, we'll see how Tapestry can do the same, and quite a bit more, for HTML forms.

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Tapestry treats public fields as if they were JavaBeans properties; since the Address object is just "dumb data", there's no need to get carried away writing getters and setters. Instead, we'll define an entity that is all public fields:

Code Block

language	java
title	src/main/java/com/example/tutorial/entities/Address.java


package com.example.tutorialtutorial1.entities;

import com.example.tutorialtutorial1.data.Honorific;

public class Address
{
    public Honorific honorific;

    public String firstName;

    public String lastName;

    public String street1;

    public String street2;

    public String city;

    public String state;

    public String zip;

    public String email;

    public String phone;
}

We also need to define the enum type, Honorific:

Code Block

language	java
title	src/main/java/com/example/tutorial/data/Honorific.java


package com.example.tutorialtutorial1.data;

public enum Honorific
{
    MR, MRS, MISS, DR
}

Address Pages

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First, we'll update the Index.tml template, to create a link to the new page:

Code Block

language	XMLxml
title	src/main/resources/com/example/tutorial/pages/Index.tml (partial)XML


    <h1>Address Book</h1>

    <ul>
        <li><t:pagelink page="address/create">Create new address</t:pagelink></li>
    </ul>

Now we need the address/Create page; lets start with an empty shell, just to test our navigation.

Code Block

language	xmlXML
title	src/main/resources/com/example/tutorial/pages/address/CreateAddress.tml	XML


<html t:type="layout" title="Create New Address"
    xmlns:t="http://tapestry.apache.org/schema/tapestry_5_3.xsd">

    <em>coming soon ...</em>

</html>

(Note: for Tapestry 5.4, make that tapestry_5_4.xsd instead.)

Next, And the corresponding class:

Code Block

language	java
title	src/main/java/com/example/tutorial/pages/address/CreateAddress.java


package com.example.tutorialtutorial1.pages.address;

public class CreateAddress
{

}

So ... why is the class named "CreateAddress" and not simply "Create"? Actually, we could have named it "Create", and the application would still work, but the longer class name is equally valid. Tapestry noticed the redundancy in the class name (com.example.tutorialtutorial1.pages.address.CreateAddress) and just stripped out the redundant suffix

Wiki Markup
{footnote}Tapestry also checks for redundant prefixes. In addition, the long name, "address/CreateAddress" is also valid.{footnote}

.

Eventually, your application will probably have more entities: perhaps you'll have a "user/Create" page and a "payment/Create" page and an "account/Create" page. You could have a bunch of different classes all named Create spread across a number of different packages. That's legal Java, but it isn't ideal. You may find yourself accidentally editing the Java code for creating an Account when your really want to be editing the code for creating a Payment.

Tapestry is encouraging you to use a more descriptive name: CreateAddress, not just Create, but it isn't making you pay the cost (in terms of longer, uglier URLs). The URL to access the page will still be http://localhost:8080/tutorial1/address/create.

And remember, regardless of the name that Tapestry assigns to your page, the template file is named like the Java class itself: CreateAddress.tml.

Info

Index pages work in folders as well. A class named com.example.tutorial.pages.address.AddressIndex would be given the name "address/Index". However, Tapestry has special rules for pages named "Index" and the rendered URL would be http://localhost:8080/tutorial1/address/. In other words, you can place Index pages in any folder and Tapestry will build a short URL for that page ... and you don't have to keep naming the classes Index (it's confusing to have many classes with the same name, even across multiple packages); instead, you can name each index page after the package that contains it. Tapestry users a smart convention to keep it all straight and generate short, to the point URLs.

Using the BeanEditForm Component

Time to start putting together the logic for this form. Tapestry has a specific component for client-side Forms: the Form component, as well as components for form controls, such as Checkbox and TextField. We'll cover those in a bit more detail later .. instead, we're again going to let Tapestry do the heavy lifting for us, via the BeanEditForm component.

Add the following to the CreateAddress template (replacing the "coming soon ..." message):

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  <t:beaneditform object="address"/>

And match that up with a property in the CreateAddress class:

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  @Property
  private Address address;

.

Tapestry actually creates a bunch of aliases for you pages; any of these aliases are valid and can appear in URLs or in the page parameter of PageLink. You can see the list in the console:

Code Block

[INFO] TapestryModule.ComponentClassResolver Available pages (12):
              (blank): com.example.tutorial1.pages.Index
   ComponentLibraries: org.apache.tapestry5.corelib.pages.ComponentLibraries
             Error404: com.example.tutorial1.pages.Error404
      ExceptionReport: org.apache.tapestry5.corelib.pages.ExceptionReport
             GameOver: com.example.tutorial1.pages.GameOver
                Guess: com.example.tutorial1.pages.Guess
                Index: com.example.tutorial1.pages.Index
          PageCatalog: org.apache.tapestry5.corelib.pages.PageCatalog
PropertyDisplayBlocks: org.apache.tapestry5.corelib.pages.PropertyDisplayBlocks
   PropertyEditBlocks: org.apache.tapestry5.corelib.pages.PropertyEditBlocks
        ServiceStatus: org.apache.tapestry5.corelib.pages.ServiceStatus
          T5Dashboard: org.apache.tapestry5.corelib.pages.T5Dashboard
       address/Create: com.example.tutorial1.pages.address.CreateAddress
address/CreateAddress: com.example.tutorial1.pages.address.CreateAddress

Tapestry users the shortest alias when constructing URLs.

Eventually, your application will probably have more entities: perhaps you'll have a "user/Create" page and a "payment/Create" page and an "account/Create" page. You could have a bunch of different classes all named Create spread across a number of different packages. That's legal Java, but it isn't ideal. You may find yourself accidentally editing the Java code for creating an Account when you really want to be editing the code for creating a Payment.

Tapestry is encouraging you to use a more descriptive name: CreateAddress, not just Create, but it isn't making you pay the cost (in terms of longer, uglier URLs). The URL to access the page will still be http://localhost:8080/tutorial1/address/create.

And remember, regardless of the name that Tapestry assigns to your page, the template file is named like the Java class itself: CreateAddress.tml.

Info

Index pages work in folders as well. A class named com.example.tutorial1.pages.address.AddressIndex would be given the name "address/Index". However, Tapestry has special rules for pages named "Index" and the rendered URL would be http://localhost:8080/tutorial1/address/. In other words, you can place Index pages in any folder and Tapestry will build a short URL for that page ... and you don't have to keep naming the classes Index (it's confusing to have many classes with the same name, even across multiple packages); instead, you can name each index page after the package that contains it. Tapestry users a smart convention to keep it all straight and generate short, to the point URLs.

Using the BeanEditForm Component

Time to start putting together the logic for this form. Tapestry has a specific component for client-side Forms: the Form component, as well as components for form controls, such as Checkbox and TextField. We'll cover those in a bit more detail later .. instead, we're again going to let Tapestry do the heavy lifting for us, via the BeanEditForm component.

Add the following to the CreateAddress template (replacing the "coming soon ..." message):

Code Block

language	xml
title	CreateAddress.tml (partial)

    <t:beaneditform object="address"/>

And match that up with a property in the CreateAddress class:

Code Block

language	java
title	CreateAddress.java (partial)

    @Property
    private Address address;

When you refresh the page, you may see a warning like the following at the top of the page:

Image Added

If you see that, it means you need to invent an HMAC passphrase for your app. Just edit your AppModule.java class (in your services package), adding a couple of lines to the contributeApplicationDefaults method like the following:

Code Block
// Set the HMAC pass phrase to secure object data serialized to client configuration.add(SymbolConstants.HMAC_PASSPHRASE, "");

but, instead of an empty string, insert a long, random string of characters (like a very long and complex password, at least 30 characters) that you keep private.

After you do that, stop the app and restart it, and click on the Create new address link again, and you'll see something like this:

Image Added

Tapestry has

When you refresh the page, you'll see the following:

Image Removed

Tapestry's done quite a bit of work here. It has created a form that includes a field for each property. Further, its it has seen that the honorific property is an enumerated type, and presented that as a drop-down list.

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The BeanEditForm must guess at the right order to present the fields; for public fields, they end up in alphabetical order

Wiki Markup
{footnote}For standard JavaBeans properties, the BeanEditForm default is in the order in which the getter methods are defined in the class (it uses line number information, if available).{footnote}

up in alphabetical order. For standard JavaBeans properties, the BeanEditForm default is in the order in which the getter methods are defined in the class (it uses line number information, if available).

A better order for these fields is the order in which they are defined in the Address class:

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We can accomplish this by using the reorder parameter of the BeanEditForm component, which is a comma separated list of property (or public field) names:

Code Block

language	xml
title	CreateAddress.tml (partial)	xml


    <t:beaneditform object="address"
        reorder="honorific,firstName,lastName,street1,street2,city,state,zip,email,phone" />

Image RemovedImage Added

Customizing labels

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No Format

title	src/main/resources/com/example/tutorial/pages/address/CreateAddress.properties


street1-label=Street 1
street2-label=Street 2
email-label=E-Mail
zip-label=Zip Code
phone-label=Phone Number

Since this is a new file (and not a change to an existing file), you may have to restart Jetty to force Tapestry to pick up the change.

Image Modified
Create Address form with field labels corrected

We can also customize the options in the drop down list. All we have to do is add some more entries to the message catalog matching the enum names to the desired labels. Update CreateAddress.properties and add:

No Format
MR=Mr. MRS=Mrs. DR=Dr.

Notice that we don't have to include an option for MISS, because that is converted to "Miss" anyway. You might just want to include it for sake of consistency ... the point is, each option label is searched for separately.

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That button is a component within the BeanEditForm component. It's not a property, so we can't just put a message into the message catalog, the way we can with the fields. Fortunately, the BeanEditForm component includes a parameter expressly for re-labeling the button. Simply change the CreateAddress component template:

Code Block

XML

language	XMLxml


    <t:beaneditform submitlabel="Create Address" object="address"
        reorder="honorific,firstName,lastName,street1,street2,city,state,zip,email,phone"/>

The default for the submitlabel parameter is "Create/Update", but here we're overriding that default to a specific value.

The final result shows the reformatting and relabelingrelabelling:

Image Modified
Create Address form with proper labels

Before continuing on to validation, a side note about message catalogs. Message catalogs are not just for re-labeling fields and options; we'll see in later chapters how message catalogs are used in the context of localization and internationalization.

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In Tapestry, when binding a parameter, the value you provide may include a prefix. The prefix guides Tapestry in how to interpret the rest of the the parameter value ... is it the name of a property? The id of a component? A message key? Most fields parameters have a default prefix, usually "prop:", that is used when you fail to provide one (this helps to make the templates as terse as possible).

Here we want to reference a message from the catalog, so we use the "message:" prefix:

Code Block

XML

language	XMLxml


    <t:beaneditform object="address" submitlabel="message:submit-label"
        reorder="honorific,firstName,lastName,street1,street2,city,state,zip,email,phone" />

And then we define the submit-label key in the message catalog:

No Format
submit-label=Create Address

At then end of the dayIn the end, the exact same HTML is sent to the client, regardless of whether you include the label text directly in the template, or indirectly in the message catalog. In the long term, the latter approach will work better if you later chose to internationalize your application.

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Edit the Address entity, and update the lastName, firstName, street1, city, state and zip fields, adding a @Validate annotation to each:

Code Block

language	java

  
  @Validate("required")
    public String firstName;

What is that string, "required"? That's how you specify the desired validation. It is a series of names that identify what type of validation is desired. A number of validators are built in, such as "required", "minLength" and "maxLength". As elsewhere, Tapestry is case insensitive.

You can apply multiple validations, by separating the validator names with commas. Some validators can be configured (with an equals sign). Thus you might say "required,minLength=5" for a field that must be specified, and must be at least five characters long.

Warning
You can easily get confused when you make a change to an entity class, such as adding the @Validate annotatation, and not see the result in the browser. Only component classes, and (most) classes in the Tapestry services layer, are live-reloaded. Data and entity objects are not reloaded, so this is one area where you need to stop and restart Jetty to see the change.

Restart the application, and refresh your browser, then hit the submit button.

Image Removed

Form with client side validations visible

This is a shot just after hitting the submit button; all the fields have been validated and pop-up error bubbles are displayed. This looks a bit cluttered, but all the bubbles, except for the one for the focus field (the field the user is actively typing into), will fade out after a moment. As you tab from field to field, Tapestry will validate your input and briefly display the error bubble. And all of this is taking place on the client side, without any communication with the application.

"required", "minLength" and "maxLength". As elsewhere, Tapestry is case insensitive.

You can apply multiple validations, by separating the validator names with commas. Some validators can be configured (with an equals sign). Thus you might say "required,minLength=5" for a field that must be specified, and must be at least five characters long.

Warning
You can easily get confused when you make a change to an entity class, such as adding the @Validate annotation, and not see the result in the browser. Only component classes, and (most) classes in the Tapestry services layer, are live-reloaded. Data and entity objects are not reloaded, so this is one area where you need to stop and restart Jetty to see the change.

Restart the application, and refresh your browser, then hit the Create Address button.

Image Added

This is a shot just after hitting the Create Address button; all the fields have been validated and errors displayed. Each field in error has been highlighted in red and had an error message addedEach field in error has been highlighted (it's a bit subtle) and marked with a red "X". Further, the label for each of the fields has also been highlighted in red, to even more clearly identify what's in error. The cursor has also been moved to the first field that's in errorerror. And all of this is taking place on the client side, without any communication with the application.

Once all the errors are corrected, and the form does submit, all validations are performed on the server side as well (just in case the client has JavaScript disabled).

So ... how about some more interesting validation than just "required or not". Tapestry has built in support for validating based on field length and several variations of field value, including regular expressions. Zip codes are pretty easy to express as a regular expression.

Code Block

language	java

  
  @Validate("required,regexp=^\\d{5}(-\\d{4})?$")
    public String zip;

Let's give it a try; restart the application and enter an "abc" for the zip code.

Image Modified
Regexp validation

This is what you'll see after typing "abc" and tabbing out of the field, then tabbing back in. It's a little hard to capture all the animation effects in a still photoclicking the Create Address button.

Note
Modern browsers will automatically validate a regexp field when the form is submitted, as shown above. Older browsers do not have that automatic support, but will still validate input, using the same decorations as for the required fields in the previous screenshot.

In any case, that's the right validation behavior, but it's the wrong message. Your users are not going to know or care about regular expressions.

Fortunately, it's easy to customize validation messages. All we need to know is the name of the property ("zip") and the name of the validator ("regexp"). We can then put an entry into the CreateAddress message catalog:

No Format
zip-regexp-message=Zip Codes are five or nine digits. Example: 02134 or 90125-1655.

Refresh the page and submit again:

Image ModifiedRegexp validation with corrected message

This trick isn't limited to just the regexp validator, it works equally well with any validator.

Let's go one step further. Turns out, we can move the regexp pattern to the message catalog as well. If you only provide the name of the validator in the @Validate annotation, Tapestry will search the containing page's message catalog of the constraint value, as well as the validation message. The constraint value for the regexp validator is the regular expression to match against.

Code Block

language	java

  
  @Validate("required,regexp")
    public String zip;

Now, just put the regular expression into the CreateAddress message catalog:

No Format
zip-regexp=^\\d{5}(-\\d{4})?$ zip-regexp-message=Zip Codes are five or nine digits. Example: 02134 or 90125-1655.

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By now you are likely curious about what happens after the form submits successfully (without validation errors), so that's what we'll focus on next.

Wiki Markup
{display-footnotes}

...

Next: Using Tapestry With Hibernate

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Address Pages

Using the BeanEditForm Component

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Customizing labels

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Old Version 16

New Version Current

Key

Address Pages

Using the BeanEditForm Component

Using the BeanEditForm Component

Customizing labels