how to solve my issue? if statement in my program....

[behedwin]

Hello
I need some help with my program.
Tho i find it hard to just ask a specific question since im not sure what i need to solve it.
I guess ppl dont want me to zip down all my java files and upload it here, not many will trust me and download it.
So ill copy paste the code i think is relevant here and hope for the best :)

I have several classes.
MainLibraryProgram is the main class
Library
Reader
MediaItem
LoanStatus
MediaCollection
ReaderCollection
and a few more.

MAINLIBRARYPROGRAM

	private void makeLoan() {

		int mediaID = readInt("Media ID: ");
		MediaItem mediaItem = library.searchMediaItem(mediaID);

		int readerID = readInt("Reader ID ");
		Reader reader = library.searchReader(readerID);

		Date date1 = new Date();
		Date date2 = new Date(date1.getYear(), date1.getMonth(), date1.getDay()+14);
		LoanStatus loanStatus = mediaItem.getLoanStatus();
		
		loanStatus.makeLoan(date1, date2, reader);
		System.out.println("User " + reader.getName() + " have loaned " + mediaItem.getName());
		System.out.println(reader.getName() + "Reader has a total of " + reader.getLoans().size() + " loans.");

	}

	private void printLoanCollection() {
		System.out.println("--------------------");
		for (LoanStatus a : library.getLoans()) {
			System.out.println(a.toString());
		}

	}

LIBRARY

import java.util.ArrayList;
import java.util.List;

public class Library {
	private ReaderCollection readerCollection = new ReaderCollection();
	private MediaCollection mediaCollection = new MediaCollection();
	List<LoanStatus> allLoans = new ArrayList<LoanStatus>();


	public void addReader(Reader reader) {
		readerCollection.addReader(reader);

	}

	public void deleteReader(int readerID) {
		readerCollection.deleteReader(readerID);
	}

	public List<Reader> getReaders() {
		return readerCollection.getReaders();
	}

	public void addMediaItem(MediaItem mediaItem) {
		mediaCollection.addMediaItem(mediaItem);

	}

	public void deleteMediaItem(int mediaID) {
		mediaCollection.deleteMediaItem(mediaID);
	}

	public List<MediaItem> getMediaItems() {
		return mediaCollection.getMediaItems();
	}

	public MediaItem searchMediaItem(int mediaID) {
		return mediaCollection.searchMediaItem(mediaID);
	}

	public Reader searchReader(int readerID) {
		return readerCollection.searchReader(readerID);

	}

	public List<LoanStatus> getLoans() {
		for (Reader reader : readerCollection.getReaders()) {
			allLoans.addAll(reader.getLoans());
		}
		return allLoans;
	}


}

READER

import java.util.ArrayList;
import java.util.List;

public class Reader {
	private String name;
	private int readerID;
	private int birthYear;
	private Address address;
	private PhoneNo phoneNo;
	private Email email;

	private List<LoanStatus> loans = new ArrayList<LoanStatus>();

	public Reader(String name, int readerID, int birthYear, Address address,
			PhoneNo phoneNo, Email email) {
		this.name = name;
		this.readerID = readerID;
		this.birthYear = birthYear;
		this.address = address;
		this.phoneNo = phoneNo;
		this.email = email;

	}

	public String getName() {
		return name;
	}

	public int getReaderID() {
		return readerID;

	}

	public int getbirthYear() {
		return birthYear;
	}

	public Address getAddress() {
		return address;
	}

	public PhoneNo getPhoneNo() {
		return phoneNo;
	}

	public Email getEmail() {
		return email;
	}

	public String toString() {
		return "Name: " + name + " Reader ID: " + readerID + " Birth Year"
				+ birthYear + " Address: " + address + " Phone Number: "
				+ phoneNo + " Email Address: " + email;

	}

	public void makeLoan(LoanStatus loan) {
		loans.add(loan);

	}

	public List<LoanStatus> getLoans() {
		return new ArrayList(loans);

	}
	

}

MEDIAITEM

public class MediaItem {
	protected String name;
	protected int mediaID;
	protected int publishYear;
	protected LoanStatus loan;

	public MediaItem(String name, int mediaID, int publishYear) {
		this.name = name;
		this.mediaID = mediaID;
		this.publishYear = publishYear;
		loan = new LoanStatus(this);

	}

	public String getName() {
		return name;
	}

	public int getMediaID() {
		return mediaID;

	}
	public int getPublishYear(){
		return publishYear;
	}
	public LoanStatus getLoanStatus(){
		return loan;
	}
	
	public String toString() {
		return name + mediaID + publishYear;

	}

}

LOANSTATUS

import java.util.Date;

public class LoanStatus {

	private MediaItem mediaItem;
	private Date startDate;
	private Date endDate;
	private Reader r;

	public LoanStatus(MediaItem mediaItem) {
		this.mediaItem = mediaItem;

	}

	public void makeLoan(Date startDate, Date endDate, Reader r) {
		this.startDate = startDate;
		this.endDate = endDate;
		this.r = r;
		r.makeLoan(this);

	}

	public boolean checkLoan() {
		return r != null;
	}


	public String toString() {
		return "\n" + "Item: " + mediaItem + " \n" + "Loan Was Made: "
				+ startDate + " \n" + "Item is to be returned: " + endDate
				+ " \n" + "Loan was made by: " + r;
	}

}

And now finaly to my question.

I am making a loan in MainLibraryProgram.
I want to make some kind of "if" statement around that.
If searchMediaItem wont return a mediaItem that is in the system it will not crash the program, but genereate a message instead.
same for searchReader

i dont know where to put this if statement
and how to type it....

if (searchReader returns nothing/no readerID && searchMediaItem returns nothing/no mediaID)
//do this
else
//do this

Any ideas or did i just ask something really stupid :p

[Tolls]

After getting the search objects then check if either are null.
If they are then display a relevant message, else do the code you currently have.

This assumes that your collection objects return null for an invalid id.