Replace HashMap keys with values in Property file in Java

up vote
4
down vote

favorite

I have to replace HashMap keys based on a property file mapping with old - new key mapping. Is the below approach best way of replacing keys?

KeyMapping.properties



newKey1 oldLKey1

newKey2 oldKey2





//Load property mapping file

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");



Enumeration<String> newKeys = properties.getKeys();

        Map<String, Object> result = new LinkedHashMap<>();



  while (newKeys.hasMoreElements()) {

    String newKey = (String) newKeys.nextElement();

    Iterator<Entry<String, Object>> iterator = mapToReplaceKeys.entrySet().iterator();



    while(iterator.hasNext()) {

       Entry<String, Object> entry = iterator.next();



      //If key matches the key in property file       

      if (entry.getKey().equals(newKey)) {



      //remove the entry from map mapToReplaceKeys

      iterator.remove();



      //add the key with the 'oldKey' and existing value

      result.put(properties.getString(newKey), entry.getValue());            

    }

  }

}

edited Nov 22 at 4:07

nullpointer

38.3k1073146

asked Nov 21 at 23:38

user679526

45731133

add a comment |

up vote
4
down vote

favorite

I have to replace HashMap keys based on a property file mapping with old - new key mapping. Is the below approach best way of replacing keys?

KeyMapping.properties



newKey1 oldLKey1

newKey2 oldKey2





//Load property mapping file

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");



Enumeration<String> newKeys = properties.getKeys();

        Map<String, Object> result = new LinkedHashMap<>();



  while (newKeys.hasMoreElements()) {

    String newKey = (String) newKeys.nextElement();

    Iterator<Entry<String, Object>> iterator = mapToReplaceKeys.entrySet().iterator();



    while(iterator.hasNext()) {

       Entry<String, Object> entry = iterator.next();



      //If key matches the key in property file       

      if (entry.getKey().equals(newKey)) {



      //remove the entry from map mapToReplaceKeys

      iterator.remove();



      //add the key with the 'oldKey' and existing value

      result.put(properties.getString(newKey), entry.getValue());            

    }

  }

}

edited Nov 22 at 4:07

nullpointer

38.3k1073146

asked Nov 21 at 23:38

user679526

45731133

add a comment |

up vote
4
down vote

favorite

I have to replace HashMap keys based on a property file mapping with old - new key mapping. Is the below approach best way of replacing keys?

KeyMapping.properties



newKey1 oldLKey1

newKey2 oldKey2





//Load property mapping file

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");



Enumeration<String> newKeys = properties.getKeys();

        Map<String, Object> result = new LinkedHashMap<>();



  while (newKeys.hasMoreElements()) {

    String newKey = (String) newKeys.nextElement();

    Iterator<Entry<String, Object>> iterator = mapToReplaceKeys.entrySet().iterator();



    while(iterator.hasNext()) {

       Entry<String, Object> entry = iterator.next();



      //If key matches the key in property file       

      if (entry.getKey().equals(newKey)) {



      //remove the entry from map mapToReplaceKeys

      iterator.remove();



      //add the key with the 'oldKey' and existing value

      result.put(properties.getString(newKey), entry.getValue());            

    }

  }

}

edited Nov 22 at 4:07

nullpointer

38.3k1073146

asked Nov 21 at 23:38

user679526

45731133

I have to replace HashMap keys based on a property file mapping with old - new key mapping. Is the below approach best way of replacing keys?

KeyMapping.properties



newKey1 oldLKey1

newKey2 oldKey2





//Load property mapping file

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");



Enumeration<String> newKeys = properties.getKeys();

        Map<String, Object> result = new LinkedHashMap<>();



  while (newKeys.hasMoreElements()) {

    String newKey = (String) newKeys.nextElement();

    Iterator<Entry<String, Object>> iterator = mapToReplaceKeys.entrySet().iterator();



    while(iterator.hasNext()) {

       Entry<String, Object> entry = iterator.next();



      //If key matches the key in property file       

      if (entry.getKey().equals(newKey)) {



      //remove the entry from map mapToReplaceKeys

      iterator.remove();



      //add the key with the 'oldKey' and existing value

      result.put(properties.getString(newKey), entry.getValue());            

    }

  }

}

java java-8 hashmap

edited Nov 22 at 4:07

nullpointer

38.3k1073146

asked Nov 21 at 23:38

user679526

45731133

edited Nov 22 at 4:07

nullpointer

38.3k1073146

asked Nov 21 at 23:38

user679526

45731133

edited Nov 22 at 4:07

nullpointer

38.3k1073146

edited Nov 22 at 4:07

nullpointer

38.3k1073146

edited Nov 22 at 4:07

nullpointer

38.3k1073146

asked Nov 21 at 23:38

user679526

45731133

asked Nov 21 at 23:38

user679526

45731133

asked Nov 21 at 23:38

user679526

45731133

add a comment |

2 Answers
2

active

oldest

votes

up vote
4
down vote

What you're essentially doing is this:

Map<String, Object> result = Collections.list(properties.getKeys())

                .stream()

                .flatMap(element -> mapToReplaceKeys.entrySet()

                        .stream()

                        .filter(entry -> entry.getKey().equals(element)))

                .collect(toMap(e -> properties.getString(e.getKey()),

                        Map.Entry::getValue,

                        (l, r) -> r,

                        LinkedHashMap::new));

or you could also do:

Map<String, Object> result = new LinkedHashMap<>();

newKeys.asIterator()

       .forEachRemaining(e -> mapToReplaceKeys.forEach((k, v) -> {

             if(k.equals(e)) result.put(properties.getString(k), v);

       }));

edited Nov 22 at 0:47

answered Nov 22 at 0:36

Aomine

36.1k62961

Iterating over a Map, to find an equal key … that feels so … wrong…
– Holger
Nov 22 at 13:11

@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 at 13:32

add a comment |

up vote
1
down vote

Don’t iterate over a Map, just to check the keys for equality. That’s what the Map’s dedicated lookup methods are for:

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");

Map<String, Object> result = new LinkedHashMap<>();



for(String newKey: properties.keySet()) {

    Object value = mapToReplaceKeys.remove(newKey);

    if(value != null) result.put(properties.getString(newKey), value);

}

Since you want to remove the mappings, you can just use remove on the Map, which will do nothing and just return null when the key is not present.

answered Nov 22 at 13:10

Holger

160k23223428

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
4
down vote

What you're essentially doing is this:

Map<String, Object> result = Collections.list(properties.getKeys())

                .stream()

                .flatMap(element -> mapToReplaceKeys.entrySet()

                        .stream()

                        .filter(entry -> entry.getKey().equals(element)))

                .collect(toMap(e -> properties.getString(e.getKey()),

                        Map.Entry::getValue,

                        (l, r) -> r,

                        LinkedHashMap::new));

or you could also do:

Map<String, Object> result = new LinkedHashMap<>();

newKeys.asIterator()

       .forEachRemaining(e -> mapToReplaceKeys.forEach((k, v) -> {

             if(k.equals(e)) result.put(properties.getString(k), v);

       }));

edited Nov 22 at 0:47

answered Nov 22 at 0:36

Aomine

36.1k62961

Iterating over a Map, to find an equal key … that feels so … wrong…
– Holger
Nov 22 at 13:11

@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 at 13:32

add a comment |

up vote
4
down vote

What you're essentially doing is this:

Map<String, Object> result = Collections.list(properties.getKeys())

                .stream()

                .flatMap(element -> mapToReplaceKeys.entrySet()

                        .stream()

                        .filter(entry -> entry.getKey().equals(element)))

                .collect(toMap(e -> properties.getString(e.getKey()),

                        Map.Entry::getValue,

                        (l, r) -> r,

                        LinkedHashMap::new));

or you could also do:

Map<String, Object> result = new LinkedHashMap<>();

newKeys.asIterator()

       .forEachRemaining(e -> mapToReplaceKeys.forEach((k, v) -> {

             if(k.equals(e)) result.put(properties.getString(k), v);

       }));

edited Nov 22 at 0:47

answered Nov 22 at 0:36

Aomine

36.1k62961

Iterating over a Map, to find an equal key … that feels so … wrong…
– Holger
Nov 22 at 13:11

@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 at 13:32

add a comment |

up vote
4
down vote

What you're essentially doing is this:

Map<String, Object> result = Collections.list(properties.getKeys())

                .stream()

                .flatMap(element -> mapToReplaceKeys.entrySet()

                        .stream()

                        .filter(entry -> entry.getKey().equals(element)))

                .collect(toMap(e -> properties.getString(e.getKey()),

                        Map.Entry::getValue,

                        (l, r) -> r,

                        LinkedHashMap::new));

or you could also do:

Map<String, Object> result = new LinkedHashMap<>();

newKeys.asIterator()

       .forEachRemaining(e -> mapToReplaceKeys.forEach((k, v) -> {

             if(k.equals(e)) result.put(properties.getString(k), v);

       }));

edited Nov 22 at 0:47

answered Nov 22 at 0:36

Aomine

36.1k62961

What you're essentially doing is this:

Map<String, Object> result = Collections.list(properties.getKeys())

                .stream()

                .flatMap(element -> mapToReplaceKeys.entrySet()

                        .stream()

                        .filter(entry -> entry.getKey().equals(element)))

                .collect(toMap(e -> properties.getString(e.getKey()),

                        Map.Entry::getValue,

                        (l, r) -> r,

                        LinkedHashMap::new));

or you could also do:

Map<String, Object> result = new LinkedHashMap<>();

newKeys.asIterator()

       .forEachRemaining(e -> mapToReplaceKeys.forEach((k, v) -> {

             if(k.equals(e)) result.put(properties.getString(k), v);

       }));

edited Nov 22 at 0:47

answered Nov 22 at 0:36

Aomine

36.1k62961

edited Nov 22 at 0:47

answered Nov 22 at 0:36

Aomine

36.1k62961

answered Nov 22 at 0:36

Aomine

36.1k62961

answered Nov 22 at 0:36

Aomine

36.1k62961

Iterating over a Map, to find an equal key … that feels so … wrong…
– Holger
Nov 22 at 13:11

@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 at 13:32

add a comment |

Iterating over a Map, to find an equal key … that feels so … wrong…
– Holger
Nov 22 at 13:11

@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 at 13:32

Iterating over a Map, to find an equal key … that feels so … wrong…
– Holger
Nov 22 at 13:11

@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 at 13:32

add a comment |

up vote
1
down vote

Don’t iterate over a Map, just to check the keys for equality. That’s what the Map’s dedicated lookup methods are for:

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");

Map<String, Object> result = new LinkedHashMap<>();



for(String newKey: properties.keySet()) {

    Object value = mapToReplaceKeys.remove(newKey);

    if(value != null) result.put(properties.getString(newKey), value);

}

Since you want to remove the mappings, you can just use remove on the Map, which will do nothing and just return null when the key is not present.

answered Nov 22 at 13:10

Holger

160k23223428

add a comment |

up vote
1
down vote

Don’t iterate over a Map, just to check the keys for equality. That’s what the Map’s dedicated lookup methods are for:

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");

Map<String, Object> result = new LinkedHashMap<>();



for(String newKey: properties.keySet()) {

    Object value = mapToReplaceKeys.remove(newKey);

    if(value != null) result.put(properties.getString(newKey), value);

}

Since you want to remove the mappings, you can just use remove on the Map, which will do nothing and just return null when the key is not present.

answered Nov 22 at 13:10

Holger

160k23223428

add a comment |

up vote
1
down vote

Don’t iterate over a Map, just to check the keys for equality. That’s what the Map’s dedicated lookup methods are for:

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");

Map<String, Object> result = new LinkedHashMap<>();



for(String newKey: properties.keySet()) {

    Object value = mapToReplaceKeys.remove(newKey);

    if(value != null) result.put(properties.getString(newKey), value);

}

Since you want to remove the mappings, you can just use remove on the Map, which will do nothing and just return null when the key is not present.

answered Nov 22 at 13:10

Holger

160k23223428

Don’t iterate over a Map, just to check the keys for equality. That’s what the Map’s dedicated lookup methods are for:

ResourceBundle properties = ResourceBundle.getBundle("KeyMapping");

Map<String, Object> result = new LinkedHashMap<>();



for(String newKey: properties.keySet()) {

    Object value = mapToReplaceKeys.remove(newKey);

    if(value != null) result.put(properties.getString(newKey), value);

}

Since you want to remove the mappings, you can just use remove on the Map, which will do nothing and just return null when the key is not present.

answered Nov 22 at 13:10

Holger

160k23223428

answered Nov 22 at 13:10

Holger

160k23223428

answered Nov 22 at 13:10

Holger

160k23223428

answered Nov 22 at 13:10

Holger

160k23223428

add a comment |

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