/**
* Copyright (C) 2022 by Martin Robillard. See https://codesample.info/about.html
*/
package e2.chapter9;
import java.util.function.Consumer;
/**
* Demonstrates how to use the Consumer interface to process card in the context
* of CardSource decorator
*
* See Section 9.4
*/
public class ConsumingDecorator implements CardSource {
private final CardSource aSource;
private final Consumer<Card> aCardConsumer;
/**
* Illustrates how to create a decorated card source
* that prints every card drawn to the console.
*/
public static void main(String[] args) {
ConsumingDecorator source = new ConsumingDecorator(new Deck(), System.out::println);
source.draw();
source.draw();
source.draw();
}
public ConsumingDecorator(CardSource pSource, Consumer<Card> pCardConsumer) {
aSource = pSource;
aCardConsumer = pCardConsumer;
}
@Override
public Card draw() {
Card card = aSource.draw();
aCardConsumer.accept(card);
return card;
}
@Override
public boolean isEmpty() {
return aSource.isEmpty();
}
}Consumer is expected
to operate via side-effects.
Consumer is expected
to operate via side-effects.
This is a functional interface
whose functional method is accept(Object).
System class contains several useful class fields and methods. It cannot be instantiated. Among the facilities provided by the System class are standard input, standard output, and error output streams; access to externally defined properties and environment variables; a means of loading files and libraries; and a utility method for quickly copying a portion of an array.
System class contains several useful class fields and methods. It cannot be instantiated. Among the facilities provided by the System class are standard input, standard output, and error output streams; access to externally defined properties and environment variables; a means of loading files and libraries; and a utility method for quickly copying a portion of an array.
String class represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class.
String class represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class.
Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings. Because String objects are immutable they can be shared. For example:
String str = "abc";
is equivalent to:
char data[] = {'a', 'b', 'c'};
String str = new String(data);
Here are some more examples of how strings can be used:
System.out.println("abc");
String cde = "cde";
System.out.println("abc" + cde);
String c = "abc".substring(2, 3);
String d = cde.substring(1, 2);
The class String includes methods for examining individual characters of the sequence, for comparing strings, for searching strings, for extracting substrings, and for creating a copy of a string with all characters translated to uppercase or to lowercase. Case mapping is based on the Unicode Standard version specified by the Character class.
The Java language provides special support for the string concatenation operator ( + ), and for conversion of other objects to strings. For additional information on string concatenation and conversion, see The Java Language Specification.
Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.
A String represents a string in the UTF-16 format in which supplementary characters are represented by surrogate pairs (see the section Unicode Character Representations in the Character class for more information). Index values refer to char code units, so a supplementary character uses two positions in a String.
The String class provides methods for dealing with Unicode code points (i.e., characters), in addition to those for dealing with Unicode code units (i.e., char values).
Unless otherwise noted, methods for comparing Strings do not take locale into account. The Collator class provides methods for finer-grain, locale-sensitive String comparison.
javac compiler may implement the operator with StringBuffer, StringBuilder, or java.lang.invoke.StringConcatFactory depending on the JDK version. The implementation of string conversion is typically through the method toString, defined by Object and inherited by all classes in Java.