Create ToString Function<?, String>: A function which returns the {@code String} representation of an object - Java Lambda Stream

Java examples for Lambda Stream:Lambda

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Introduction

The following code shows how to get To String Function

Demo Code

import java.lang.reflect.Array;
import java.util.function.Function;

public class Main{
    public static void main(String[] argv){
        System.out.println(getToStringFunction());
    }//ww  w .  ja va  2 s . com
    /**
     * A function which returns the {@code String} representation of an object.
     * For arrays, a readable {@code String} representation is returned.
     */
    private static final Function<?, String> TO_STRING_FUNCTION = o -> {
        return o.getClass().isArray() ? toString(o) : o.toString();
    };
    /**
     * @return a function that creates readable {@code String} representations of arrays.
     */
    static <T> Function<T, String> getToStringFunction() {
        @SuppressWarnings("unchecked")
        Function<T, String> func = (Function<T, String>) TO_STRING_FUNCTION;
        return func;
    }

    private static String toString(Object array) {
        int length = Array.getLength(array);
        if (length == 0) {
            return "[]";
        }

        StringBuilder b = new StringBuilder();
        b.append('[');
        for (int i = 0;; i++) {
            b.append(Array.get(array, i));
            if (i == length - 1) {
                return b.append(']').toString();
            }
            b.append(", ");
        }
    }
}

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