If condition in lambda expression to change value in java

Question

This is a code snippet that I want to modify.

fullAlert.getSupportingData().forEach( data ->      
    dataMap.put(data.getKey(), data.getValue())
);

I want to check if data.getValue() does return empty or null. If so then

dataMap.put(data.getKey(), data.getValue())

Else I want to replace backslashes

dataMap.put(data.getKey(), data.getValue().replace("\\","\\\\"))

I am new to lambda expressions.

Panagiotis Bougioukos · Accepted Answer · 2021-03-31 18:32:23Z

1

You probably mean the ternary operator not a lambda expression. That makes sense based on what you ask for.

fullAlert.getSupportingData().forEach(data -> dataMap.put(data.getKey(), data.getValue() != null && !data.getValue().isEmpty()? data.getValue().replace("\\","\\\\") : data.getValue()));

answered Mar 31, 2021 at 18:32

Panagiotis Bougioukos

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2 Comments

hc_dev Over a year ago

Lambda is marked by ->. But substitute a simple if by [ternary]() usually has impact on readability. Optional could ease both here: readability and empty/null checks😜

Panagiotis Bougioukos Over a year ago

@hc_dev regarding the question however it was more probable that the OP wanted something like that instead of an If/Else statement. Most programmers would not need help to form an if/else statement. Now maybe he could not open the brackets on the body of the lambda function. Only OP knows what needs for real.

hc_dev · Accepted Answer · 2021-03-31 18:44:26Z

0

Are you familiar with if-statements? They work inside lambdas too. You have to open/close a block using curly braces after the arrow:

fullAlert.getSupportingData().forEach( data -> {
    String value = data.getValue(); // default
    if (value != null && !value.isBlank()) {
       value = value.replace("\\","\\\\")); // special
    }
    dataMap.put(data.getKey(), value); // always put into map
});

edited Mar 31, 2021 at 18:44

answered Mar 31, 2021 at 18:38

hc_dev

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