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bengi - guava map

This commit is contained in:
Slavisa Avramovic 2016-06-09 15:00:56 +02:00
parent 635a5aa5ea
commit 8525795755
2 changed files with 112 additions and 114 deletions
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136
guava/src/test/java/org/baeldung/guava/GuavaMapFromSet.java
View File

@ -11,91 +11,91 @@ import com.google.common.base.Function;
public class GuavaMapFromSet<K, V> extends AbstractMap<K, V> {
private class SingleEntry implements Entry<K, V> {
private K key;
private class SingleEntry implements Entry<K, V> {
private K key;
public SingleEntry( K key) {
this.key = key;
}
public SingleEntry(K key) {
this.key = key;
}
@Override
public K getKey() {
return this.key;
}
@Override
public K getKey() {
return this.key;
}
@Override
public V getValue() {
V value = GuavaMapFromSet.this.cache.get(this.key);
if (value == null) {
value = GuavaMapFromSet.this.function.apply(this.key);
GuavaMapFromSet.this.cache.put(this.key, value);
}
return value;
}
@Override
public V getValue() {
V value = GuavaMapFromSet.this.cache.get(this.key);
if (value == null) {
value = GuavaMapFromSet.this.function.apply(this.key);
GuavaMapFromSet.this.cache.put(this.key, value);
}
return value;
}
@Override
public V setValue( V value) {
throw new UnsupportedOperationException();
}
}
@Override
public V setValue(V value) {
throw new UnsupportedOperationException();
}
}
private class MyEntrySet extends AbstractSet<Entry<K, V>> {
private class MyEntrySet extends AbstractSet<Entry<K, V>> {
public class EntryIterator implements Iterator<Entry<K, V>> {
private Iterator<K> inner;
public class EntryIterator implements Iterator<Entry<K, V>> {
private Iterator<K> inner;
public EntryIterator() {
this.inner = MyEntrySet.this.keys.iterator();
}
public EntryIterator() {
this.inner = MyEntrySet.this.keys.iterator();
}
@Override
public boolean hasNext() {
return this.inner.hasNext();
}
@Override
public boolean hasNext() {
return this.inner.hasNext();
}
@Override
public Map.Entry<K, V> next() {
K key = this.inner.next();
return new SingleEntry(key);
}
@Override
public Map.Entry<K, V> next() {
K key = this.inner.next();
return new SingleEntry(key);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
private Set<K> keys;
private Set<K> keys;
public MyEntrySet( Set<K> keys) {
this.keys = keys;
}
public MyEntrySet(Set<K> keys) {
this.keys = keys;
}
@Override
public Iterator<Map.Entry<K, V>> iterator() {
return new EntryIterator();
}
@Override
public Iterator<Map.Entry<K, V>> iterator() {
return new EntryIterator();
}
@Override
public int size() {
return this.keys.size();
}
@Override
public int size() {
return this.keys.size();
}
}
}
private WeakHashMap<K, V> cache;
private Set<Entry<K, V>> entries;
private Function<? super K, ? extends V> function;
private WeakHashMap<K, V> cache;
private Set<Entry<K, V>> entries;
private Function<? super K, ? extends V> function;
public GuavaMapFromSet( Set<K> keys, Function<? super K, ? extends V> function) {
this.function = function;
this.cache = new WeakHashMap<K, V>();
this.entries = new MyEntrySet(keys);
}
public GuavaMapFromSet(Set<K> keys, Function<? super K, ? extends V> function) {
this.function = function;
this.cache = new WeakHashMap<K, V>();
this.entries = new MyEntrySet(keys);
}
@Override
public Set<Map.Entry<K, V>> entrySet() {
return this.entries;
}
@Override
public Set<Map.Entry<K, V>> entrySet() {
return this.entries;
}
}

90
guava/src/test/java/org/baeldung/guava/GuavaMapFromSetTests.java
View File

@ -13,54 +13,52 @@ import com.google.common.base.Function;
public class GuavaMapFromSetTests {
@Test
public void givenStringSet_whenMapsToElementLength_thenCorrect() {
Function<Integer, String> function = new Function<Integer, String>() {
@Test
public void givenStringSet_whenMapsToElementLength_thenCorrect() {
Function<Integer, String> function = new Function<Integer, String>() {
@Override
public String apply(Integer from) {
return Integer.toBinaryString(from);
}
};
Set<Integer> set = new TreeSet<>(Arrays.asList(32, 64, 128));
Map<Integer, String> map = new GuavaMapFromSet<Integer, String>(set, function);
assertTrue(map.get(32).equals("100000")
&& map.get(64).equals("1000000")
&& map.get(128).equals("10000000"));
}
@Override
public String apply(Integer from) {
return Integer.toBinaryString(from.intValue());
}
};
Set<Integer> set = (Set<Integer>) new TreeSet<Integer>(Arrays.asList(
32, 64, 128));
Map<Integer, String> map = new GuavaMapFromSet<Integer, String>(set,
function);
assertTrue(map.get(32).equals("100000")
&& map.get(64).equals("1000000")
&& map.get(128).equals("10000000"));
}
@Test
public void givenIntSet_whenMapsToElementBinaryValue_thenCorrect() {
Function<String, Integer> function = new Function<String, Integer>() {
@Test
public void givenIntSet_whenMapsToElementBinaryValue_thenCorrect() {
Function<String, Integer> function = new Function<String, Integer>() {
@Override
public Integer apply(String from) {
return from.length();
}
};
Set<String> set = new TreeSet<>(Arrays.asList(
"four", "three", "twelve"));
Map<String, Integer> map = new GuavaMapFromSet<String, Integer>(set,
function);
assertTrue(map.get("four") == 4 && map.get("three") == 5
&& map.get("twelve") == 6);
}
@Override
public Integer apply(String from) {
return from.length();
}
};
Set<String> set = (Set<String>) new TreeSet<String>(Arrays.asList(
"four", "three", "twelve"));
Map<String, Integer> map = new GuavaMapFromSet<String, Integer>(set,
function);
assertTrue(map.get("four") == 4 && map.get("three") == 5
&& map.get("twelve") == 6);
}
@Test
public void givenSet_whenNewSetElementAddedAndMappedLive_thenCorrect() {
Function<String, Integer> function = new Function<String, Integer>() {
@Test
public void givenSet_whenNewSetElementAddedAndMappedLive_thenCorrect() {
Function<String, Integer> function = new Function<String, Integer>() {
@Override
public Integer apply(String from) {
return from.length();
}
};
Set<String> set = (Set<String>) new TreeSet<String>(Arrays.asList(
"four", "three", "twelve"));
Map<String, Integer> map = new GuavaMapFromSet<String, Integer>(set,
function);
set.add("one");
assertTrue(map.get("one") == 3 && map.size()==4);
}
@Override
public Integer apply(String from) {
return from.length();
}
};
Set<String> set = new TreeSet<>(Arrays.asList(
"four", "three", "twelve"));
Map<String, Integer> map = new GuavaMapFromSet<String, Integer>(set,
function);
set.add("one");
assertTrue(map.get("one") == 3 && map.size() == 4);
}
}