com.github.netty.core.util.CaseInsensitiveKeyMap Maven / Gradle / Ivy
package com.github.netty.core.util;
import java.util.*;
/**
* 不敏感大小写的map
*
* A Map implementation that uses case-insensitive (using {@link
* Locale#ENGLISH}) strings as keys.
*
* Keys must be instances of {@link String}. Note that this means that
* null keys are not permitted.
*
* This implementation is not thread-safe.
*
* @param Type of values placed in this Map.
*/
public class CaseInsensitiveKeyMap extends AbstractMap {
private final Map map;
public CaseInsensitiveKeyMap() {
this.map = new LinkedHashMap<>();
}
public CaseInsensitiveKeyMap(int initialCapacity) {
map = new LinkedHashMap<>(initialCapacity);
}
@Override
public V get(Object key) {
return map.get(Key.getInstance(key));
}
@Override
public V put(String key, V value) {
Key caseInsensitiveKey = Key.getInstance(key);
if (caseInsensitiveKey == null) {
throw new NullPointerException();
}
return map.put(caseInsensitiveKey, value);
}
/**
* {@inheritDoc}
*
* Use this method with caution. If the input Map contains duplicate
* keys when the keys are compared in a case insensitive manner then some
* values will be lost when inserting via this method.
*/
@Override
public void putAll(Map m) {
super.putAll(m);
}
@Override
public boolean containsKey(Object key) {
return map.containsKey(Key.getInstance(key));
}
@Override
public V remove(Object key) {
return map.remove(Key.getInstance(key));
}
@Override
public Set> entrySet() {
return new EntrySet<>(map.entrySet());
}
private static class EntrySet extends AbstractSet> {
private final Set> entrySet;
public EntrySet(Set> entrySet) {
this.entrySet = entrySet;
}
@Override
public Iterator> iterator() {
return new EntryIterator<>(entrySet.iterator());
}
@Override
public int size() {
return entrySet.size();
}
}
private static class EntryIterator implements Iterator> {
private final Iterator> iterator;
public EntryIterator(Iterator> iterator) {
this.iterator = iterator;
}
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public Entry next() {
Entry entry = iterator.next();
return new EntryImpl<>(entry.getKey().getKey(), entry.getValue());
}
@Override
public void remove() {
iterator.remove();
}
}
private static class EntryImpl implements Entry {
private final String key;
private final V value;
public EntryImpl(String key, V value) {
this.key = key;
this.value = value;
}
@Override
public String getKey() {
return key;
}
@Override
public V getValue() {
return value;
}
@Override
public V setValue(V value) {
throw new UnsupportedOperationException();
}
}
private static class Key {
private final String key;
private final String lcKey;
private Key(String key) {
this.key = key;
this.lcKey = key.toLowerCase(Locale.ENGLISH);
}
public static Key getInstance(Object o) {
if (o instanceof String) {
return new Key((String) o);
}
return null;
}
public String getKey() {
return key;
}
@Override
public int hashCode() {
return lcKey.hashCode();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
Key other = (Key) obj;
return lcKey.equals(other.lcKey);
}
}
}