Java का Builder Pattern

public class Main {
	static class Pizza {
		String size; boolean cheese;
		Pizza(String size, boolean cheese) { this.size = size; this.cheese = cheese; }
	}
	public static void main(String[] args) {
		// Avoids a telescoping constructor for every combination of optional toppings
		Pizza p = new Pizza("large", true);
		System.out.println(p.size + " " + p.cheese);
	}
}

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// Define the class Main
public class Main {
	// Define the class Pizza
	static class Pizza {
		String size; boolean cheese;
		private Pizza(Builder b) { this.size = b.size; this.cheese = b.cheese; }
		static class Builder {
			String size; boolean cheese;
			Builder size(String size) { this.size = size; return this; }
			Builder cheese(boolean cheese) { this.cheese = cheese; return this; }
			Pizza build() { return new Pizza(this); }
		}
	}
	// Program entry point: the JVM starts running here
	public static void main(String[] args) {
		Pizza p = new Pizza.Builder().size("medium").cheese(true).build();
		// Print a line to the console
		System.out.println(p.size + " " + p.cheese);
	}
}

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public class Main {
	static class Order {
		final String item; String note;
		private Order(Builder b) { this.item = b.item; this.note = b.note; }
		static class Builder {
			final String item; // mandatory -- required by the Builder's own constructor
			String note; // optional
			Builder(String item) { this.item = item; }
			Builder note(String note) { this.note = note; return this; }
			Order build() { return new Order(this); }
		}
	}
	public static void main(String[] args) {
		Order o = new Order.Builder("Book").note("Gift wrap").build();
		System.out.println(o.item + " " + o.note);
	}
}

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public class Main {
	static final class Point {
		final int x, y; // no setters -- immutable once built
		private Point(Builder b) {
			if (b.x < 0 || b.y < 0) throw new IllegalArgumentException("negative coordinates");
			this.x = b.x; this.y = b.y;
		}
		static class Builder {
			int x, y;
			Builder x(int x) { this.x = x; return this; }
			Builder y(int y) { this.y = y; return this; }
			Point build() { return new Point(this); }
		}
	}
	public static void main(String[] args) {
		Point p = new Point.Builder().x(3).y(4).build();
		System.out.println(p.x + "," + p.y);
	}
}

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// Define the class Main
public class Main {
	// Define the class HttpRequestBuilder
	static class HttpRequestBuilder {
		String url; String method = "GET"; String header;
		HttpRequestBuilder url(String url) { this.url = url; return this; }
		HttpRequestBuilder method(String method) { this.method = method; return this; }
		HttpRequestBuilder header(String header) { this.header = header; return this; }
		String build() { return method + " " + url + " [" + header + "]"; }
	}
	// Program entry point: the JVM starts running here
	public static void main(String[] args) {
		// Create a new HttpRequestBuilder object and store it in request
		String request = new HttpRequestBuilder().url("/api/users").method("POST").header("Auth").build();
		// Print a line to the console
		System.out.println(request);
	}
}

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