validate="person" on the Form.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!-- We need a doctype to allow us to use special characters like   
     We use a "strict" DTD to make IE follow the alignment rules. -->
     
<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_4.xsd">
<body class="container">
    <h3>Bean Validators</h3>
    Here is a second demonstration of Bean Validation, this time using a domain entity, Person, as the bean.
    <div class="eg">
            
        <t:form t:id="personForm" class="form-horizontal" validate="person">
            <div class="form-group">
                <t:label for="firstName" class="col-sm-3"/>
                <div class="col-sm-3">
                    <t:textfield t:id="firstName" value="person.firstName"/>
                </div>
                <div class="col-sm-6">
                    <p class="form-control-static">
                        ${person.firstName}
                        <span class="text-muted">
                            (not null, size max = 10)
                        </span>
                    </p>
                </div>
            </div>
            <div class="form-group">
                <t:label for="lastName" class="col-sm-3"/>
                <div class="col-sm-3">
                    <t:textfield t:id="lastName" value="person.lastName"/>
                </div>
                <div class="col-sm-6">
                    <p class="form-control-static">
                        ${person.lastName}
                        <span class="text-muted">
                            (not null, size max = 10)
                        </span>
                    </p>
                </div>
            </div>
            <div class="form-group">
                <div class="col-sm-3 col-sm-offset-3">
                    <t:submit/>
                </div>
            </div>
        </t:form>
            
    </div>
    
    Notice that we set <code>validate="person"</code> on the Form.<br/><br/>
    References: 
    <a href="http://tapestry.apache.org/bean-validation.html">Bean Validation</a>, 
    <a href="http://tapestry.apache.org/5.4/apidocs/org/apache/tapestry5/corelib/components/Form.html">Form</a>, 
    <a href="http://tapestry.apache.org/5.4/apidocs/org/apache/tapestry5/corelib/components/TextField.html">TextField</a>.
    <br/><br/>
    <t:pagelink page="Index">Home</t:pagelink><br/><br/>
        
    <t:tabgroup>
        <t:sourcecodetab src="/web/src/main/java/jumpstart/web/pages/examples/input/BeanValidators.tml"/>
        <t:sourcecodetab src="/web/src/main/java/jumpstart/web/pages/examples/input/BeanValidators.java"/>
        <t:sourcecodetab src="/web/src/main/resources/META-INF/assets/css/examples/plain.css"/>
        <t:sourcecodetab src="/business/src/main/java/jumpstart/business/domain/person/Person.java"/>
    </t:tabgroup>
</body>
</html>
package jumpstart.web.pages.examples.input;
import jumpstart.business.domain.person.Person;
import jumpstart.util.ExceptionUtil;
import org.apache.tapestry5.PersistenceConstants;
import org.apache.tapestry5.annotations.Import;
import org.apache.tapestry5.annotations.InjectComponent;
import org.apache.tapestry5.annotations.Persist;
import org.apache.tapestry5.annotations.Property;
import org.apache.tapestry5.corelib.components.Form;
@Import(stylesheet = "css/examples/plain.css")
public class BeanValidators {
    // Screen fields
    @Property
    @Persist(PersistenceConstants.FLASH)
    private Person person;
    // Generally useful bits and pieces
    @InjectComponent
    private Form personForm;
    // The code
    // PersonForm bubbles up the PREPARE_FOR_RENDER event during form render.
    void onPrepareForRender() {
        // If fresh start, make sure there's a Person object available.
        if (personForm.isValid()) {
            if (person == null) {
                // Create object for the form fields to overlay.
                person = new Person();
            }
        }
    }
    // PersonForm bubbles up the PREPARE_FOR_SUBMIT event when it is submitted
    void onPrepareForSubmit() {
        // Create object for the form fields to overlay.
        person = new Person();
    }
    // PersonForm bubbles up the VALIDATE event when it is submitted
    void onValidateFromPersonForm() {
        if (personForm.getHasErrors()) {
            // We get here only if a server-side validator detected an error.
            return;
        }
        try {
            // In a real application we might do something like create a Person here.
            // personManagerService.createPerson(person);
        }
        catch (Exception e) {
            // Display the cause. In a real system we would try harder to get a user-friendly message.
            personForm.recordError(ExceptionUtil.getRootCauseMessage(e));
        }
    }
}
.eg {
                margin: 20px 0;
                padding: 14px;
                border: 1px solid #ddd;
                border-radius: 6px;
                -webkit-border-radius: 6px;
                -mox-border-radius: 6px;
}
package jumpstart.business.domain.person;
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.PrePersist;
import javax.persistence.PreUpdate;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Version;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
/**
 * The Person entity.
 */
@Entity
@SuppressWarnings("serial")
public class Person implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(nullable = false)
    private Long id;
    @Version
    @Column(nullable = false)
    private Integer version;
    @Column(length = 10, nullable = false)
    @NotNull
    @Size(max = 10)
    private String firstName;
    @Column(length = 10, nullable = false)
    @NotNull
    @Size(max = 10)
    private String lastName;
    
    @Enumerated(EnumType.STRING)
    @NotNull
    private Regions region;
    @Temporal(TemporalType.DATE)
    @NotNull
    private Date startDate;
    public String toString() {
        final String DIVIDER = ", ";
        
        StringBuilder buf = new StringBuilder();
        buf.append(this.getClass().getSimpleName() + ": ");
        buf.append("[");
        buf.append("id=" + id + DIVIDER);
        buf.append("version=" + version + DIVIDER);
        buf.append("firstName=" + firstName + DIVIDER);
        buf.append("lastName=" + lastName + DIVIDER);
        buf.append("region=" + region + DIVIDER);
        buf.append("startDate=" + startDate);
        buf.append("]");
        return buf.toString();
    }
    // Default constructor is required by JPA.
    public Person() {
    }
    public Person(String firstName, String lastName, Regions region, Date startDate) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
        this.region = region;
        this.startDate = startDate;
    }
    // The need for an equals() method is discussed at http://www.hibernate.org/109.html
    
    @Override
    public boolean equals(Object obj) {
        return (obj == this) || (obj instanceof Person) && id != null && id.equals(((Person) obj).getId());
    }
    // The need for a hashCode() method is discussed at http://www.hibernate.org/109.html
    @Override
    public int hashCode() {
        return id == null ? super.hashCode() : id.hashCode();
    }
    @PrePersist
    @PreUpdate
    public void validate() throws ValidationException {
    }
    public Long getId() {
        return id;
    }
    public Integer getVersion() {
        return version;
    }
    public void setVersion(Integer version) {
        this.version = version;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public Regions getRegion() {
        return region;
    }
    public void setRegion(Regions region) {
        this.region = region;
    }
    public Date getStartDate() {
        return startDate;
    }
    public void setStartDate(Date startDate) {
        this.startDate = startDate;
    }
}