// APS101, Winter 2009: Lecture 10 (Jan. 29)
//
// Review: last time we looked at class interactions.
// Specifically, we looked at the aggregation relationship.
// (that's when one object contains another object)
//
// Local variable:
// a variable that's defined within a method.
// other methods can't see or use this local variable.
//
// Global/Instance variable:
// defined within a class.
// visible by all methods.
//
// We also wrote 2 classes:
// Musician.java and Band.java

Musician m1 = new Musician("LilWayne", 10);
m1.getSalary()
m1.toString()
Band b = new Band(m1, m1, m1);
b.getTotalSalary()
Musician m2 = new Musician("Gene Simmons", 100);
m1.isEqual(m2)
Musician m3 = new Musician("LilWayne", 100);
m1.isEqual(m3)
// We wrote a setSalary() method in Musician
Musician m1 = new Musician("LilWayne", 10);
Band b = new Band(m1, m1, m1);
b.getTotalSalary()
m1.setSalary(15)
m1.getSalary()
b.getTotalSalary()
b.toString() // default toString() method is called!
// We then wrote a toString() method in Band
Musician m1 = new Musician("LilWayne", 10);
Band b = new Band(m1, m1, m1);
b.toString()
"abc" + 'd' // we can concatenate a String with char
Musician m1 = new Musician("LilWayne", 10);
Band b = new Band(m1, m1, m1);
b.toString()
// We added instance variable numBands to Musician,
// and wrote getNumBands() and joinedBand().
Musician m1 = new Musician("LilWayne", 10);
m1.getNumBands()
Musician m2 = new Musician("PDiddy", 10);
Musician m3 = new Musician("Gene Simmons", 100);
Band b = new Band(m1, m2, m3);
b.getTotalSalary()
b.toString()
m2.setSalary(50)
b.toString()
m1.getNumBands()
m2.getNumBands()
m3.getNumBands()
Band b2 = new Band(m1, m1, m1);
m1.getNumBands()
// We wrote method isWithinBudget(double) in Band
Musician m2 = new Musician("PDiddy", 10);
Band b2 = new Band(m2, m2, m2);
b2.isWithinBudget(10)
b2.isWithinBudget(30)
b2.isWithinBudget(100)
// We wrote method isEqual(Band) in Band
Musician m1 = new Musician("LilWayne", 10);
Musician m2 = new Musician("PDiddy", 50);
Musician m3 = new Musician("50Cent", 0.5);
Band b = new Band(m1, m2, m3);
Band b2 = new Band(m1, m2, m3);
m1.getNumBands()
b.isEqual(b2)
Band b3 = new Band(m1, m3, m2);
b.isEqual(b3) // it's false, because the order is different!
// So let's change the method to take the order into account
Musician m1 = new Musician("LilWayne", 10);
Musician m2 = new Musician("PDiddy", 50);
Musician m3 = new Musician("50Cent", 0.5);
Band b1 = new Band(m1, m2, m3);
Band b2 = new Band(m1, m3, m2);
b1.isEqual(b2) // true - this is good!
Band b3 = new Band(m1, m1, m1);
b1.isEqual(b3) // false - this is also good!
Band b1 = new Band(m1, m2, m2);
Band b2 = new Band(m1, m1, m2);
b1.isEqual(b2) // true?? this is bad... why?