Newbie: ArrayList.indexOf help

Greetings,

Given the following code, how would I search my ArrayList of Center
objects for specific instance variable _sCenterId. I would assume I
use indexOf or Contains, but getting lost in the reference to my
Center object...

import java.util.ArrayList;
import java.util.Iterator;

class Main
{

    @SuppressWarnings("static-access")
    public static void main(String[] args)
    {
        Customer myCust = new Customer();
        myCust.set_sCustomerName("Arizona Software");
        System.out.println("Customer Name:" +
myCust.get_sCustomerName());

        myCust.add_aCenters();
        myCust.numCenters++;
 
myCust._aCenters.get(myCust.numCenters-1).set_sCenterId("PHX");
 
myCust._aCenters.get(myCust.numCenters-1).set_sStartDate("2008-01-01");
 
myCust._aCenters.get(myCust.numCenters-1).set_sEndDate("2100-12-31");

        myCust.add_aCenters();
        myCust.numCenters++;
 
myCust._aCenters.get(myCust.numCenters-1).set_sCenterId("TUC");
 
myCust._aCenters.get(myCust.numCenters-1).set_sStartDate("2008-01-01");
 
myCust._aCenters.get(myCust.numCenters-1).set_sEndDate("2008-08-01");

        for ( Center tempCenter : myCust._aCenters)
        {
            System.out.println("Center ID:" +
tempCenter.get_sCenterId() +
                               " Start Date:" +
tempCenter.get_sStartDate() +
                               " End Date:" +
tempCenter.get_sEndDate());
        }
        // HOW DO I SEARCH FOR _sCenterId = "PHX"
        int val = myCust._aCenters.indexOf("PHX");
        System.out.println("VAL:" + val);

    }
}

class Customer
{
    String _sCustomerName;
    ArrayList<Center> _aCenters = new ArrayList<Center>();
    static int numCenters=0;

    Customer()
    {
       // _aCenters.add(new Center());
    }
    void add_aCenters()
    {
        _aCenters.add(new Center());
    }

    String get_sCustomerName()
    {
        return _sCustomerName;
    }

    void set_sCustomerName(String sCustomerName)
    {
        _sCustomerName = sCustomerName;
    }

}

class Center
{
    String _sCenterId;
    private String _sStartDate;
    private String _sEndDate;

    Center()
    {

    }

    Center(String sCenterId)
    {
        set_sCenterId(sCenterId);
    }

    String get_sCenterId()
    {
        return _sCenterId;
    }

    void set_sCenterId(String sCenterId)
    {
        _sCenterId = sCenterId;
    }

    public String get_sStartDate()
    {
        return _sStartDate;
    }

    public void set_sStartDate(String sStartDate)
    {
        this._sStartDate = sStartDate;
    }

    public String get_sEndDate()
    {
        return _sEndDate;
    }

    public void set_sEndDate(String sEndDate)
    {
        this._sEndDate = sEndDate;
    }
}