Maintenance script: Repair batch-0003 pages from live compare

2026-03-27T00:29:07Z

Repair batch-0003 pages from live compare

← Older revision		Revision as of 00:29, 27 March 2026
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	double getValueForPeriod (int periodNumber) {		double getValueForPeriod (int periodNumber) {
	try {		try {
	return _values[periodNumber];		return _values[periodNumber];
	} catch (ArrayIndexOutOfBoundsException e) {		} catch (ArrayIndexOutOfBoundsException e) {
	return 0;		return 0;
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	double getValueForPeriod (int periodNumber) {		double getValueForPeriod (int periodNumber) {
	if (periodNumber >= _values.length) return 0;		if (periodNumber >= _values.length) return 0;
	return _values[periodNumber];		return _values[periodNumber];
	}		}

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	[[Refactoring]]		Refactoring

imported>Unknown at 05:27, 7 February 2021

2021-02-07T05:27:53Z

New page

__TOC__
= Chapter 10 Making Method Calls Simpler =
== Rename Method ==
The name of a method does not reveal its purpose.
''Change the name of the method''

http://zeropage.org/~reset/zb/data/RenameMethod.gif

== Add Parameter ==
A method needs more information from its caller.
''Add a parameter for an object that can pass on this information''

http://zeropage.org/~reset/zb/data/AddParameter.gif
== Remove Parameter ==
A parameter is no longer used by the method body.
''Remove it''

http://zeropage.org/~reset/zb/data/RemoveParameter.gif
== Separate Query from Modifier ==
You have a method that returns a value but also changes the state of an object.
''Create two methods, one for the query and one for the modification''

http://zeropage.org/~reset/zb/data/SeparateQueryFromModifier.gif
== Parameterize Method ==
Several methods do similar things but with different values contained in the method body.
''Create one method that uses a parameter for the different values''

http://zeropage.org/~reset/zb/data/ParameterizeMethod.gif
== Replace Paramter with Explicit Method ==
You have a method that runs different code depending on the values of an enumerated parameter.
''Create a separate method for each value of the parameter''
void setValue (String name, int value) {
if (name.equals("height"))
_height = value;
if (name.equals("width"))
_width = value;
Assert.shouldNeverReachHere();
}

void setHeight (int arg) {
_height = arg;
}
void setWidth (int arg) {
_width = arg;
}

== Preserve Whole Object ==
You are getting several values from an object and passing these values as parameters in a method call.
''Send the whole object instead''
int low = daysTempRange().getLow();
int high = days.TempRange().getHight();
withinPlan = plan.withinRange (low, high);

withinPlan = plan.withinRange (daysTempRange());

== Replace Parameter with Method ==
An object invokes a method, then passes the result as a parameter for a method. The receiver can also invoke this method.
''Remove the parameter and let the receiver invoke the method''
int basePrice = _quantity * _itemPrice;
discountLevel = getDiscountLevel ();
double finalPrice = discountedPrice (basePrice, discountLevel);

int basePrice = _quantity * _itemPrice;
double finalPrice = discountedPrice (basePrice);

== Introduce Parameter Object ==
You have a group of parameters that naturally go together.
''Replace them with an object''

http://zeropage.org/~reset/zb/data/IntroduceParameterObject.gif
== Remove Setting Method ==
A field should be set at creation time and never altered.
''Remove any setting method for that field''

http://zeropage.org/~reset/zb/data/RemoveSettingMethod.gif
== Hide Method ==
A method is not used by any other class.
''Make the method private''

http://zeropage.org/~reset/zb/data/HideMethod.gif
== Replace Constructor with Factory Method ==
You want to do more that simple construction when you create an object.
''Replace the constructor with a factory method''

Emplyee (int type) {
_type = type;
}

static Emplyee create (int type) {
return new Emplyee (type);
}

== Encapsulate Downcast ==
A method returns an object that needs to be downcasted by its callers.
''Move the downcast to within the method''
Object lastReading () {
return readings.lastElement ();
}

Reading lastReading () {
return (Reading) readings.lastElement ();
}

== Replace Error Code with Exception ==
A method returns a special code to indicate an error.
''Throw an exception instead''
int withdraw(int amount) {
if (amount > _balance)
return -1;
else {
_balance -= amount;
return 0;
}
}

void withdraw(int amount) throws BalanceException {
if (amount > _balance) throw new BalanceException ();
_balance -= amount;
}

== Replace Exception with Test ==
You are throwing an exception on a condition the caller could have checked first.
''Change the caller to make the test first''
double getValueForPeriod (int periodNumber) {
try {
return _values[periodNumber];
} catch (ArrayIndexOutOfBoundsException e) {
return 0;
}
}

double getValueForPeriod (int periodNumber) {
if (periodNumber >= _values.length) return 0;
return _values[periodNumber];
}

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[[Refactoring]]

Refactoring/MakingMethodCallsSimpler - Revision history

Maintenance script: Repair batch-0003 pages from live compare

imported>Unknown at 05:27, 7 February 2021