如何更改与具有相同键的HashMap列表中的键关联的值？

Question

I have one List of totally 13 HashMaps in my input. Each HashMap has only 2 Keys "fieldName" and "accessibilityType" and corresponding values:

"fieldAccessibility": [
    {
        "fieldName": "firstName",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "lastName",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "avatarUrl",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "username",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "birthDate",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "phoneNumbers",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "email",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "language",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "externalId",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "externalCode",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "punchBadgeId",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "minor",
        "accessibilityType": "EDITABLE"
    },
    {
        "fieldName": "seniorityDate",
        "accessibilityType": "EDITABLE"
    }
]

I am trying to iterate through this and change the value of "accessibilityType" into "READ" where "fieldName" is "birthDate". Can someone please say the efficient way to do this. This is my attempt so far to just read and print each key-value pair:

final List<HashMap<String, String>> list = some code to get the input;
    for (HashMap<String, String> m : list)
    {
        for (HashMap.Entry<String, String> e : m.entrySet())
        {
            String key = e.getKey();
            String value = e.getValue();

            System.out.println("SEE HERE TEST " + key + " = " + value);

        }}

Answer 1

it can be done as follows using forEach as of JDK-8:

list.forEach(map -> {
      String fieldName = map.get("fieldName");
      if("birthDate".equals(fieldName)) map.put("accessibilityType", "READ");
});

Answer 2

You can do it like so,

List<Map<String, String>> updatedMaps = list.stream()
        .map(m -> m.entrySet().stream().collect(Collectors.toMap(
        Map.Entry::getKey,
        e -> m.containsValue("birthDate") && e.getKey().equals("accessibilityType") ? "READ" : e.getValue())))
        .collect(Collectors.toList());

Go through each map while mapping it into a new one. The keys remain the same and only values may change. If your map contains the key birthDate and if the current entry's key is accessibilityType , then incorporate READ as the new value for that map entry. Otherwise leave the existing value as it is. Finally collect all the new maps into a result container.