/**
 *	Cities can have multiple zip codes.
 *	For our simplified model, for the multiple case, we'll choose one (the first in our data source)
 *	We'll use a 5-digit zip code
 */

public class Foo {

	private String name;
	private int id;

	//-------------------------------------------------------
	// Static Factory Constructor Methods (for convenience and clarity)

	/** Returns new Foo using static factory constructor method */
	public static Foo fromNameId(String aName, int anId) {
		return new Foo(aName, anId);
	}

	//-------------------------------------------------------
	// Traditional Constructors


	/** Returns new Foo using parameters */
	public Foo(String aName, int anId) {
		this.name = aName;
		this.id = anId;
	}

	/** Returns new Foo via copy constructor -- preserves the original */
	public Foo(Foo source) {
		this(source.getName(), source.getId());
	}

	//-------------------------------------------------------
	// Utility

	/** Returns nice string describing this object (typically one-line string) */
	@Override
	public String toString() {
		return String.format("%s -- (%d)", this.getName(), this.getId());
	}

	//-------------------------------------------------------
	// Accessing

	public String getName() {
		return this.name;
	}

	public int getId() {
		return this.id;
	}

	public void setName(String aName) {
		this.name = aName;
	}

	public void setId(int anId) {
		this.id = anId;
	}

	//-------------------------------------------------------
	// Equality

	/** Returns hash code */
	@Override
	public int hashCode() {
		//note different technique for object (name) vs primitive (id)
		int hashCode = 7;
		hashCode = 31 * hashCode + (this.getName() != null ? this.getName().hashCode() : 0);
		hashCode = 31 * hashCode + this.getId();
		return hashCode;
	}

	/** Returns true if this object equals parameter "o" */
	@Override
	public boolean equals(Object o) {
		if (o == this)
			return true;
		if (!(o instanceof Foo))
			return false;
		Foo other = (Foo)o;
		//use safe equals for objects, use "==" for primitives
		return
			safeEquals(this.getName(), other.getName())
				&& (this.getId() == other.getId());
	}

	//-------------------------------------------------------
	// Helper Methods (any methods we think of that make things simpler)

	/** Returns true if a is equal to be (considering nulls) */
	private boolean safeEquals(Object a, Object b) {
		//If only one is nil, then false, use XOR*/
		if (a==null ^ b==null)
			return false;
		//We now know both are null, or not null, check for condition #1 first*/
		//If either is null, they both are
		if (a==null)
			return true;
		//Finally a simple equals
		return a.equals(b);
	}

}