Replace HashMap keys with values in Property file in Java
4
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 '18 at 4:07
nullpointer
44.6k1096184
asked Nov 21 '18 at 23:38
user679526user679526
45731133
add a comment |
4
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 '18 at 4:07
nullpointer
44.6k1096184
asked Nov 21 '18 at 23:38
user679526user679526
45731133
add a comment |
4
4
4
1
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 '18 at 4:07
nullpointer
44.6k1096184
asked Nov 21 '18 at 23:38
user679526user679526
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
java java-8 hashmap
edited Nov 22 '18 at 4:07
nullpointer
44.6k1096184
asked Nov 21 '18 at 23:38
user679526user679526
45731133
edited Nov 22 '18 at 4:07
nullpointer
44.6k1096184
asked Nov 21 '18 at 23:38
user679526user679526
45731133
edited Nov 22 '18 at 4:07
nullpointer
44.6k1096184
edited Nov 22 '18 at 4:07
nullpointer
44.6k1096184
edited Nov 22 '18 at 4:07
nullpointer
44.6k1096184
44.6k1096184
asked Nov 21 '18 at 23:38
user679526user679526
45731133
asked Nov 21 '18 at 23:38
user679526user679526
45731133
asked Nov 21 '18 at 23:38
user679526user679526
45731133
45731133
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
4
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);
}));
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
Iterating over aMap, to find an equal key … that feels so … wrong…
– Holger
Nov 22 '18 at 13:11
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
add a comment |
1
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 '18 at 13:10
HolgerHolger
163k23231438
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
4
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);
}));
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
Iterating over aMap, to find an equal key … that feels so … wrong…
– Holger
Nov 22 '18 at 13:11
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
add a comment |
4
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);
}));
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
Iterating over aMap, to find an equal key … that feels so … wrong…
– Holger
Nov 22 '18 at 13:11
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
add a comment |
4
4
4
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);
}));
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
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);
}));
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
edited Nov 22 '18 at 0:47
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
answered Nov 22 '18 at 0:36
AomineAomine
41.8k74071
41.8k74071
Iterating over aMap, to find an equal key … that feels so … wrong…
– Holger
Nov 22 '18 at 13:11
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
add a comment |
Iterating over aMap, to find an equal key … that feels so … wrong…
– Holger
Nov 22 '18 at 13:11
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
Iterating over a
Map, to find an equal key … that feels so … wrong…– Holger
Nov 22 '18 at 13:11
Iterating over a
Map, to find an equal key … that feels so … wrong…– Holger
Nov 22 '18 at 13:11
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
@Holger now that you mention it, I feel so silly...
– Aomine
Nov 22 '18 at 13:32
add a comment |
1
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 '18 at 13:10
HolgerHolger
163k23231438
add a comment |
1
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 '18 at 13:10
HolgerHolger
163k23231438
add a comment |
1
1
1
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 '18 at 13:10
HolgerHolger
163k23231438
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 '18 at 13:10
HolgerHolger
163k23231438
answered Nov 22 '18 at 13:10
HolgerHolger
163k23231438
answered Nov 22 '18 at 13:10
HolgerHolger
163k23231438
answered Nov 22 '18 at 13:10
HolgerHolger
163k23231438
163k23231438
add a comment |
add a comment |
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