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The <code class="cCode">PlayerBean</code> class defines the access methods for the persistent fields as follows:
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
public abstract String getPlayerId();
public abstract void setPlayerId(String id);

public abstract String getName();
public abstract void setName(String name);

public abstract String getPosition();
public abstract void setPosition(String position);

public abstract double getSalary();
public abstract void setSalary(double salary);<a name="wp79883"> </a>
</pre></div>
<a name="wp79884"> </a><p class="pBody">
The name of an access method begins with <code class="cCode">get</code> or <code class="cCode">set</code>, followed by the capitalized name of the persistent or relationship field. For example, the accessor methods for the <code class="cCode">salary</code> field are <code class="cCode">getSalary</code> and <code class="cCode">setSalary</code>. This naming convention is similar to that of JavaBeans components.
</p>
<a name="wp79887"> </a><h5 class="pHeading4">
Access Methods for Relationship Fields
</h5>
<a name="wp79888"> </a><p class="pBody">
In the <code class="cCode">RosterApp</code> application, since a player can belong to multiple teams, a <code class="cCode">PlayerEJB</code> instance may be related to many <code class="cCode">TeamEJB</code> instances. To specify this relationship, the deployment descriptor of <code class="cCode">PlayerEJB</code> defines a relationship field named <code class="cCode">teams</code>. In the <code class="cCode">PlayerBean</code> class, the access methods for the <code class="cCode">teams</code> relationship field are as follows:
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
public abstract Collection getTeams();
public abstract void setTeams(Collection teams);<a name="wp79890"> </a>
</pre></div>
<a name="wp79891"> </a><h4 class="pHeading3">
Finder and Select Methods
</h4>
<a name="wp83215"> </a><p class="pBody">
Finder and select methods use EJB QL queries to return objects and state information of entity beans using container-managed persistence.
</p>
<a name="wp83220"> </a><p class="pBody">
A select method is similar to a finder method in the following ways:
</p>
<div class="pSmartList1"><ul class="pSmartList1">
<a name="wp79895"> </a><div class="pSmartList1"><li>A select method can return a local or remote interface (or a collection of interfaces).</li></div>
<a name="wp79896"> </a><div class="pSmartList1"><li>A select method queries a database.</li></div>
<a name="wp79898"> </a><div class="pSmartList1"><li>The deployment descriptor specifies an EJB QL query for a select method.</li></div>
<a name="wp79899"> </a><div class="pSmartList1"><li>The entity bean class does not implement the select method.</li></div>
</ul></div>
<a name="wp79900"> </a><p class="pBody">
However, a select method differs significantly from a finder method:
</p>
<div class="pSmartList1"><ul class="pSmartList1">
<a name="wp79901"> </a><div class="pSmartList1"><li>A select method can return a persistent field (or a collection thereof) of a related entity bean. A finder method can return only a local or remote interface (or a collection of interfaces).</li></div>
<a name="wp79902"> </a><div class="pSmartList1"><li>Since it is not exposed in any of the local or remote interfaces, a select method cannot be invoked by a client. It can be invoked only by the methods implemented within the entity bean class. A select method is usually invoked by either a business or home method.</li></div>
<a name="wp79903"> </a><div class="pSmartList1"><li>A select method is defined in the entity bean class. For bean-managed persistence, a finder method is defined in the entity bean class, but for container-managed persistence it is not.</li></div>
</ul></div>
<a name="wp79904"> </a><p class="pBody">
The <code class="cCode">PlayerBean</code> class defines these select methods:
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
public abstract Collection ejbSelectLeagues(LocalPlayer player)
&nbsp;&nbsp;throws FinderException;
public abstract Collection ejbSelectSports(LocalPlayer player)
&nbsp;&nbsp;throws FinderException;<a name="wp79905"> </a>
</pre></div>
<a name="wp79906"> </a><p class="pBody">
The signature for a select method must follow these rules:
</p>
<div class="pSmartList1"><ul class="pSmartList1">
<a name="wp79907"> </a><div class="pSmartList1"><li>The prefix of the method name must be <code class="cCode">ejbSelect</code>.</li></div>
<a name="wp79908"> </a><div class="pSmartList1"><li>The access control modifier must be <code class="cCode">public</code>.</li></div>
<a name="wp79909"> </a><div class="pSmartList1"><li>The method must be declared as <code class="cCode">abstract</code>.</li></div>
<a name="wp79910"> </a><div class="pSmartList1"><li>The <code class="cCode">throws</code> clause must include the <code class="cCode">javax.ejb.FinderException</code>.</li></div>
</ul></div>
<a name="wp79911"> </a><h4 class="pHeading3">
Business Methods
</h4>
<a name="wp79912"> </a><p class="pBody">
Since clients cannot invoke select methods, the <code class="cCode">PlayerBean</code> class wraps them in the <code class="cCode">getLeagues</code> and <code class="cCode">getSports</code> business methods:
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
public Collection getLeagues() throws FinderException {

&nbsp;&nbsp;LocalPlayer player = 
&nbsp;&nbsp;&nbsp;&nbsp;(team.LocalPlayer)context.getEJBLocalObject();
&nbsp;&nbsp;return ejbSelectLeagues(player);
}

public Collection getSports() throws FinderException {

&nbsp;&nbsp;LocalPlayer player = 
&nbsp;&nbsp;&nbsp;&nbsp;(team.LocalPlayer)context.getEJBLocalObject();
&nbsp;&nbsp;return ejbSelectSports(player);
}<a name="wp79914"> </a>
</pre></div>
<a name="wp79915"> </a><h4 class="pHeading3">
Entity Bean Methods
</h4>
<a name="wp79916"> </a><p class="pBody">
Because the container handles persistence, the life-cycle methods in the <code class="cCode">PlayerBean</code> class are nearly empty.
</p>
<a name="wp79918"> </a><p class="pBody">
The <code class="cCode">ejbCreate</code> method initializes the bean instance by assigning the input arguments to the persistent fields. At the end of the transaction that contains the create call, the container inserts a row into the database. Here is the source code for the <code class="cCode">ejbCreate</code> method:
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
public String ejbCreate (String id, String name, 
    String position, double salary) throws CreateException {

    setPlayerId(id);
    setName(name);
    setPosition(position);
    setSalary(salary);
    return null;
}<a name="wp79920"> </a>
</pre></div>
<a name="wp83227"> </a><p class="pBody">
The <code class="cCode">ejbPostCreate</code> method returns <code class="cCode">void</code> and it has the same input parameters as the <code class="cCode">ejbCreate</code> method. If you want to set a relationship field to initialize the bean instance, you should do so in the <code class="cCode">ejbPostCreate</code> method. You may not set a relationship field in the <code class="cCode">ejbCreate</code> method.
</p>
<a name="wp79922"> </a><p class="pBody">
Except for a debug statement, the <code class="cCode">ejbRemove</code> method in the <code class="cCode">PlayerBean</code> class is empty. The container invokes <code class="cCode">ejbRemove</code> before removing the entity object.
</p>
<a name="wp79925"> </a><p class="pBody">
The container automatically synchronizes the state of the entity bean with the database. After the container loads the bean's state from the database, it invokes the <code class="cCode">ejbLoad</code> method. In like manner, before storing the state in the database, the container invokes the <code class="cCode">ejbStore</code> method.
</p>
<a name="wp79929"> </a><h3 class="pHeading2">
Local Home Interface
</h3>
<a name="wp79931"> </a><p class="pBody">
The local home interface defines the <code class="cCode">create</code>, finder, and home methods that may be invoked by local clients. 
</p>
<a name="wp79933"> </a><p class="pBody">
The syntax rules for a <code class="cCode">create</code> method follow:
</p>
<div class="pSmartList1"><ul class="pSmartList1">
<a name="wp79934"> </a><div class="pSmartList1"><li>The name begins with <code class="cCode">create</code>.</li></div>
<a name="wp79935"> </a><div class="pSmartList1"><li>It has the same number and types of arguments as its matching <code class="cCode">ejbCreate</code> method in the entity bean class. </li></div>
<a name="wp79936"> </a><div class="pSmartList1"><li>It returns the local interface type of the entity bean. </li></div>
<a name="wp79937"> </a><div class="pSmartList1"><li>The <code class="cCode">throws</code> clause includes the exceptions specified by the <code class="cCode">throws</code> clause of the corresponding <code class="cCode">ejbCreate</code> method.</li></div>
<a name="wp79938"> </a><div class="pSmartList1"><li>The <code class="cCode">throws</code> clause contains the <code class="cCode">javax.ejb.CreateException</code>. </li></div>
</ul></div>
<a name="wp79940"> </a><p class="pBody">
These rules apply for a finder method:
</p>
<div class="pSmartList1"><ul class="pSmartList1">
<a name="wp79941"> </a><div class="pSmartList1"><li>The name begins with <code class="cCode">find</code>.</li></div>
<a name="wp79942"> </a><div class="pSmartList1"><li>The return type is the entity bean's local interface type, or a collection of those types. </li></div>
<a name="wp79943"> </a><div class="pSmartList1"><li>The <code class="cCode">throws</code> clause contains the <code class="cCode">javax.ejb.FinderException</code>.</li></div>
<a name="wp79944"> </a><div class="pSmartList1"><li>The <code class="cCode">findByPrimaryKey</code> method must be defined.</li></div>
</ul></div>
<a name="wp79946"> </a><p class="pBody">
An excerpt of the <code class="cCode">LocalPlayerHome</code> interface follows.
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
package team;

import java.util.*;
import javax.ejb.*;

public interface LocalPlayerHome extends EJBLocalHome {
    
    public LocalPlayer create (String id, String name, 
        String position, double salary)
        throws CreateException;
    
    public LocalPlayer findByPrimaryKey (String id)
        throws FinderException;
    
    public Collection findByPosition(String position) 
        throws FinderException;
     ...
    public Collection findByLeague(LocalLeague league) 
        throws FinderException;
    ...
  }<a name="wp79947"> </a>
</pre></div>
<a name="wp79949"> </a><h3 class="pHeading2">
Local Interface
</h3>
<a name="wp79953"> </a><p class="pBody">
This interface defines the business and access methods that a local client may invoke. The <code class="cCode">PlayerBean</code> class implements two business methods: <code class="cCode">getLeagues</code> and <code class="cCode">getSports</code>. It also defines several <code class="cCode">get</code> and <code class="cCode">set</code> access methods for the persistent and relationship fields. The <code class="cCode">set</code> methods are hidden from the bean's clients because they are not defined in the <code class="cCode">LocalPlayer</code> interface. However, the <code class="cCode">get</code> methods are exposed to the clients by the interface:
</p>
<div class="pPreformattedRelative"><pre class="pPreformattedRelative">
package team;

import java.util.*;
import javax.ejb.*;

public interface LocalPlayer extends EJBLocalObject {

    public String getPlayerId();
    public String getName();
    public String getPosition();
    public double getSalary();
    public Collection getTeams();

    public Collection getLeagues() throws FinderException;
    public Collection getSports() throws FinderException;
}<a name="wp79955"> </a>
</pre></div>
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