Method Cascading

Here is an example of our "regular" code approach.

private void runDemo() throws IOException  {
	Report farmCommodityReport = new Report();
	farmCommodityReport.showLine("Farm Report");
	farmCommodityReport.newline();
	farmCommodityReport.showLine("Commodities:");
	farmCommodityReport.newline();
	farmCommodityReport.showLines(commodityNames());
	farmCommodityReport.newline();
	farmCommodityReport.showLine("Trends:");
	farmCommodityReport.newline();
	farmCommodityReport.showLine("Corn up $0.05");
	farmCommodityReport.showLine("Soybeans down -$0.20");
	farmCommodityReport.showLine("Wheat unchanged");
	farmCommodityReport.writeAndView("FarmReport.txt");
}

Example -- With Method Cascading

Here the code is doing the same thing
as the previous example.

But we use method cascading to lighten up our code.

private void runDemoWithMethodCascading() throws IOException  {
	Report farmCommodityReport = new Report();
	farmCommodityReport
		.showLine("Farm Report")
		.newline()
		.showLine("Commodities:")
		.newline()
		.showLines(commodityNames())
		.newline()
		.showLine("Trends:")
		.newline()
		.showLine("Corn up $0.05")
		.showLine("Soybeans down -$0.20")
		.showLine("Wheat unchanged")
		.writeAndView("FarmReport.txt");
}

Returning 'this'

This is the most common way to support support cascading.

Just two steps:

Set the return type to the class you are coding in
Return "this"

Three examples (methods) are shown that support support cascading. In each of these three we do the two steps.

public class Report {
	private String contents;

	public Report show(Object o)  {
		basicShow(o);
		return this;
	}

	public Report showLine(Object o)  {
		basicShow(o);
		newline();
		return this;
	}

	public Report showLines(List<?> lines)  {
		for (Object each: lines)
			showLine(each);
		return this;
	}

Returning new Object of Correct Type

This is another approach to support method cascading. We construct a new object which is the same type as "this" object (i.e. type "Report").

Just two steps:

Set the return type to the class you are coding in
Construct a new object of that type.

Report Class

public class Report {
	private String contents;

	public 1Report copyReport()  {
		return 2new Report(this);
	}