Java/Collections Data Structure/LinkedHashMap
Содержание
- 1 Check if a particular element exists in Java LinkedHashSet
- 2 Check if a particular key exists in Java LinkedHashMap example
- 3 Check if a particular value exists in Java LinkedHashMap example
- 4 Copy all elements of Java LinkedHashSet to an Object Array
- 5 Get Set view of Keys from Java LinkedHashMap
- 6 Get Size of Java LinkedHashMap
- 7 Implementing a Least-Recently-Used (LRU) Cache
- 8 Iterate through the values of Java LinkedHashMap
- 9 Remove all values from Java LinkedHashMap
- 10 Remove value from Java LinkedHashMap
- 11 Simple Java LinkedHashMap
Check if a particular element exists in Java LinkedHashSet
<source lang="java">
import java.util.LinkedHashSet; public class Main {
public static void main(String[] args) { LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>(); lhashSet.add(new Integer("1")); lhashSet.add(new Integer("2")); lhashSet.add(new Integer("3")); System.out.println(lhashSet.contains(new Integer("3"))); }
}
</source>
Check if a particular key exists in Java LinkedHashMap example
<source lang="java">
import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); boolean blnExists = lHashMap.containsKey("3"); System.out.println(blnExists); }
}
</source>
Check if a particular value exists in Java LinkedHashMap example
<source lang="java">
import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); boolean blnExists = lHashMap.containsValue("Two"); System.out.println(blnExists); }
}
</source>
Copy all elements of Java LinkedHashSet to an Object Array
<source lang="java">
import java.util.LinkedHashSet; public class Main {
public static void main(String[] args) { LinkedHashSet<Integer> lhashSet = new LinkedHashSet<Integer>(); lhashSet.add(new Integer("1")); lhashSet.add(new Integer("2")); lhashSet.add(new Integer("3")); Object[] objArray = lhashSet.toArray(); for (Object inte: objArray){ System.out.println(inte); } }
}
</source>
Get Set view of Keys from Java LinkedHashMap
<source lang="java">
import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Set; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); Set st = lHashMap.keySet(); Iterator itr = st.iterator(); while (itr.hasNext()){ System.out.println(itr.next()); } st.remove("2"); boolean blnExists = lHashMap.containsKey("2"); System.out.println(blnExists); }
} /* 1 2 3 false
- /
</source>
Get Size of Java LinkedHashMap
<source lang="java">
import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); System.out.println(lHashMap.size()); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); System.out.println(lHashMap.size()); Object obj = lHashMap.remove("2"); System.out.println(lHashMap.size()); }
}
</source>
Implementing a Least-Recently-Used (LRU) Cache
<source lang="java">
import java.util.Collections; import java.util.LinkedHashMap; import java.util.Map; public class Main {
public static void main(String[] argv) throws Exception { final int MAX_ENTRIES = 100; Map cache = new LinkedHashMap(MAX_ENTRIES + 1, .75F, true) { public boolean removeEldestEntry(Map.Entry eldest) { return size() > MAX_ENTRIES; } }; Object key = "key"; Object value = "value"; cache.put(key, value); Object o = cache.get(key); if (o == null && !cache.containsKey(key)) { } cache = (Map) Collections.synchronizedMap(cache); }
}
</source>
Iterate through the values of Java LinkedHashMap
<source lang="java">
import java.util.Collection; import java.util.Iterator; import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); Collection c = lHashMap.values(); Iterator itr = c.iterator(); while (itr.hasNext()){ System.out.println(itr.next()); } }
}
</source>
Remove all values from Java LinkedHashMap
<source lang="java">
import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); lHashMap.clear(); System.out.println(lHashMap.size()); }
}
</source>
Remove value from Java LinkedHashMap
<source lang="java">
import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,String> lHashMap = new LinkedHashMap<String,String>(); lHashMap.put("1", "One"); lHashMap.put("2", "Two"); lHashMap.put("3", "Three"); Object obj = lHashMap.remove("2"); System.out.println(obj + " was Removed"); }
}
</source>
Simple Java LinkedHashMap
<source lang="java">
import java.util.LinkedHashMap; public class Main {
public static void main(String[] args) { LinkedHashMap<String,Integer> lHashMap = new LinkedHashMap<String,Integer>(); lHashMap.put("One", new Integer(1)); lHashMap.put("Two", new Integer(2)); // retrieve value using Object get(Object key) method of Java LinkedHashMap class Object obj = lHashMap.get("One"); System.out.println(obj); }
}
</source>