Finding special strings within special strings in strings with Regex

Question

There is a HashMap I have which has keys and values inside. I want to replace keys with the values from the map in a string.

In the string, keys are written as this @keyName or @"keyName" these should be replaced with map.get("keyName")

Lets say our map is this

"key1" : "2"  
"key2" : "3"  
"key3" : "4"  
"key 4" : "5"
"key-5" : "6"

So if we process the string "hello world, I am @key1 years old.", it will become "hello world, I am 2 years old."

Instead of @key1, we could use @"key1". If we use it without quotes, a white space (space character) or EOF should follow the key name and the key name shouldn't have white space in it. But if the key name has a white space in it, then it should be in quotes.

And if we process the string "hello world, I am @"key@"key1"" years old.", at first step it should replace the special string inside the special string and become "hello world, I am @"key2" years old." and then with the second step it should be "hello world, I am 3 years old."

I have already done it for one special string, it doesn't recognize the special string within the special string. Here is the code:

private static Pattern specialStringPattern = Pattern.compile("@\"([^\"]*?)\"|@\\S+");

/** this replaces the keys inside a string with their values.
 * for example @keyName or @"keyName" is replaced with the value of the keyName. */
public static String specialStrings(String s) {
    Matcher matcher = specialStringPattern.matcher(s);
    while (matcher.find()) {
        String text = matcher.group();
        text = text.replace("@","").replaceAll("\"","");
        s = s.replace(matcher.group(),map.get(text));
    }
    return s;
}

Sorry for my English, and my lack of Regex knowledge. I think it should be easy to get the answer by modifying the code a little bit.

Here is some examples of what I need:

There is @key1 apples on the table.  
There is 2 apples on the table.

There is @"key1" apples on the table.  
There is 2 apples on the table.

There is @key 4 apples on the table.
There is null 4 apples on the table.

There is @"key 4" apples on the table.
There is 5 apples on the table.

There is @key@key2 apples on the table.
There is @key3 apples on the table. (second step)
There is 4 apples on the table. (final output)

There is @"key @"key3"" apples on the table.
There is @"key 4" apples on the table. (second step)
There is 5 apples on the table. (final output)

There is @"key @key3" apples on the table.
There is @"key 4" apples on the table. (second step)
There is 5 apples on the table. (final output)

There is @"key @key3 " apples on the table.
There is @"key 4 " apples on the table. (second step)
There is null apples on the table. (final output)

There is @key-5 apples on the table.
There is 6 apples on the table.

Is the solution acceptable for you? stackoverflow.com/a/3655963/2027465 — Vitalii Pro
– Vitalii Pro, Commented Nov 22, 2016 at 14:46
@VitaliyPro I don't think it is applicable. I thought I explained the rules clearly. Thanks. — ossobuko
– ossobuko, Commented Nov 22, 2016 at 15:56

Atmahadli · Accepted Answer · 2016-11-22 19:13:42Z

1

I made regex that matching your example here: https://regex101.com/r/nudYEl/2

@(\"[\w\s]+\")|(?!@(\w+)@(\w+))@(\w+)

and you just need to modify your function to recursive:

public static String specialStrings(String s) {
    Matcher matcher = specialStringPattern.matcher(s);
    boolean findAgain = false;
    while (matcher.find()) {
        String text = matcher.group();
        text = text.replace("@","").replaceAll("\"","");
        s = s.replace(matcher.group(),map.get(text));
        findAgain = true;
    }
    if (findAgain) return specialStrings(s);
    return s;
}

[Update]
regex: https://regex101.com/r/nudYEl/4

@(\"[\w\s-]+\")|(?!@([\w-]+)@([\w-]+))@([\w-]+)

edited Nov 22, 2016 at 19:13

answered Nov 22, 2016 at 16:20

Atmahadli

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3 Comments

ossobuko Over a year ago

There is a problem with the characters like '-'. The keys often use a dash between words. Like "key-1". Sorry I missed that.

ossobuko Over a year ago

Update to this: @(\"[^\"^@]+\")|(?!@[^\"^@^\s]+@)(@[^\"^@^\s]+) This way only @ and " couldn't be used in the key name.

Atmahadli Over a year ago

cool! that worked too, I think you don't need to use ^ for every character inside [...] I try this work too @(\"[^\"@]+\")|(?!@[^\"@\s]+@)(@[^\"@\s]+)

Bohemian · Accepted Answer · 2016-11-22 22:23:41Z

0

Don't use regex:

for (boolean hit = true; hit;) {
    hit = false;
    for (String key : map.keySet()) {
        if (str.contains("@\"" + key + "\"")) {
            str = str.replace("@\"" + key + "\"", map.get(key));
            hit = true;
        } else if (str.contains("@" + key  )) {
            str = str.replace("@" + key + "", map.get(key));
            hit = true;
        }
    }
}

edited Nov 22, 2016 at 22:23

answered Nov 22, 2016 at 14:47

Bohemian♦

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3 Comments

ossobuko Over a year ago

This doesn't recognize the inner special String. The first quote of the inner special string finishes the special string.

Bohemian Over a year ago

@ossobuko you're right. I edited my answer to something different that works (tested too!)

ossobuko Over a year ago

Oh no! You are going through thousands of keys. This is a frequently used method.

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