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A Java 8 fluent map interface
package org.fissore.steroids;
import java.util.*;
import java.util.function.Function;
import java.util.stream.Stream;
/**
* SteroidMap is a {@link Map} on steroids.
* It decorates {@link Map} providing a fluent interface and a shorter syntax. It allows you to navigate a map structure without using casts.
* It doesn't require any code to work with other frameworks/libraries: if they know how to deal with {@link Map}s, they work with SteroidMap as well.
* Custom implementations should implement SteroidMap and delegate the actual storage to a backing map implementation, such as {@link HashMap} or {@link java.util.concurrent.ConcurrentHashMap}.
*
* @param the type of the keys
*/
public interface SteroidMap extends Map {
/* content manipulation */
/**
* {@link #put(Object, Object) Puts} a value if not null. Fluent version of {@link #put(Object, Object)}
*
* @param key key with which the specified value is to be associated
* @param value value to be associated with the specified key
* @return this instance
*/
default SteroidMap add(K key, Object value) {
if (value != null) {
put(key, value);
}
return this;
}
/**
* {@link #put(Object, Object) Puts} all non null values from given maps into this map. Fluent version of {@link #putAll(Map)}
*
* @param sources mappings to be stored in this map
* @return this instance
* @see #addAll(Stream)
*/
default SteroidMap addAll(Map... sources) {
return addAll(Stream.of(sources));
}
/**
* {@link #put(Object, Object) Puts} all non null values from given maps into this map. Fluent version of {@link #putAll(Map)}
*
* @param sources mappings to be stored in this map
* @return this instance
* @see #addAll(Stream)
*/
default SteroidMap addAll(Collection> sources) {
return addAll(sources.stream());
}
/**
* {@link #put(Object, Object) Puts} all non null values from given maps into this map. Fluent version of {@link #putAll(Map)}
*
* @param sources mappings to be stored in this map
* @return this instance
*/
default SteroidMap addAll(Stream> sources) {
synchronized (this) {
sources.forEach(source -> source.forEach(this::add));
}
return this;
}
/**
* {@link #put(Object, Object) Puts} non null keys from source into this map. If keys is not specified, it behaves as {@link #addAll(Map[])}
*
* @param source the map to add to this map
* @param keys if specified, only given keys will be added
* @return this instance
*/
default SteroidMap addFrom(Map source, K... keys) {
return addFrom(source, new HashSet<>(Arrays.asList(keys)));
}
/**
* {@link #put(Object, Object) Puts} non null keys from source into this map. If keys is not specified, it behaves as {@link #addAll(Map[])}
*
* @param source the map to add to this map
* @param keys if specified, only these keys will be added
* @return this instance
*/
default SteroidMap addFrom(Map source, Collection keys) {
if (source == null) {
return this;
}
if (keys.size() == 0) {
return addAll(source);
}
synchronized (this) {
source.entrySet().stream()
.filter(e -> keys.contains(e.getKey()))
.forEach(e -> add(e.getKey(), e.getValue()));
}
return this;
}
/**
* Renames the specified key, if present. It runs a in a synchronized block
*
* @param oldKey the old key
* @param newKey the new key
* @return this instance
*/
default SteroidMap renameKey(K oldKey, K newKey) {
synchronized (this) {
if (!containsKey(oldKey)) {
return this;
}
put(newKey, get(oldKey));
remove(oldKey);
}
return this;
}
/**
* Removes given keys from this map. Fluent version of {@link #remove(Object)}
*
* @param keys the keys to remove
* @return this instance
* @see #del(Stream)
*/
default SteroidMap del(K... keys) {
return del(Stream.of(keys));
}
/**
* Removes given keys from this map. Fluent version of {@link #remove(Object)}
*
* @param keys the keys to remove
* @return this instance
* @see #del(Stream)
*/
default SteroidMap del(Collection keys) {
return del(keys.stream());
}
/**
* Removes given keys from this map. Fluent version of {@link #remove(Object)}
*
* @param keys the keys to remove
* @return this instance
*/
default SteroidMap del(Stream keys) {
synchronized (this) {
keys.forEach(this::remove);
}
return this;
}
/* content extraction */
/**
* If given key is {@link #valued(Object) valued}, it's applied to provided valueReturner. Otherwise, defaultValue is returned.
* Both checking if the key is {@link #valued(Object) valued} and applying valueReturner run in a synchronized block
*
* @param key the key
* @param defaultValue the value to return if key is not {@link #valued(Object) valued}
* @param valueReturner the function to apply the key to
* @param the return type
* @return either value from map or defaultValue
*/
default V defaultIfMissing(K key, V defaultValue, Function valueReturner) {
synchronized (this) {
if (valued(key)) {
return valueReturner.apply(key);
}
}
return defaultValue;
}
/**
* {@link #get(Object) Gets} given key and cast it to a Long
*
* @param key the key
* @return value associated to key casted to Long
*/
default long l(K key) {
return (Long) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Long. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to Long. defaultValue if key is not {@link #valued(Object) valued}
*/
default long l(K key, Long defaultValue) {
return defaultIfMissing(key, defaultValue, this::l);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Integer
*
* @param key the key
* @return value associated to key casted to Integer
*/
default int i(K key) {
return (Integer) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Integer. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to Integer. defaultValue if key is not {@link #valued(Object) valued}
*/
default int i(K key, Integer defaultValue) {
return defaultIfMissing(key, defaultValue, this::i);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Double
*
* @param key the key
* @return value associated to key casted to Double
*/
default double d(K key) {
return (Double) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Double. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to Double. defaultValue if key is not {@link #valued(Object) valued}
*/
default double d(K key, Double defaultValue) {
return defaultIfMissing(key, defaultValue, this::d);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Float
*
* @param key the key
* @return value associated to key casted to Float
*/
default float f(K key) {
return (Float) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Float. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to Float. defaultValue if key is not {@link #valued(Object) valued}
*/
default float f(K key, Float defaultValue) {
return defaultIfMissing(key, defaultValue, this::f);
}
/**
* {@link #get(Object) Gets} given key and cast it to a String
*
* @param key the key
* @return value associated to key casted to String
*/
default String s(K key) {
return (String) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a String. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to String. defaultValue if key is not {@link #valued(Object) valued}
*/
default String s(K key, String defaultValue) {
return defaultIfMissing(key, defaultValue, this::s);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Boolean
*
* @param key the key
* @return value associated to key casted to Boolean
*/
default boolean b(K key) {
return (Boolean) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Boolean. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to Boolean. defaultValue if key is not {@link #valued(Object) valued}
*/
default boolean b(K key, Boolean defaultValue) {
return defaultIfMissing(key, defaultValue, this::b);
}
/**
* {@link #get(Object) Gets} given key and cast it to type V
*
* @param key the key
* @param the return type
* @return value associated to key casted to type V
*/
default V o(K key) {
return (V) get(key);
}
/**
* {@link #get(Object) Gets} given key and transform it using given function
*
* @param key the key
* @param transformer a function used to change original value
* @param the return type
* @return value associated to key and transformed using function
*/
default V o(K key, Function transformer) {
return transformer.apply(get(key));
}
/**
* {@link #get(Object) Gets} given key and cast it to type of given Class
*
* @param key the key
* @param clazz the clazz, useful only to make the compiler happy about type V
* @param the return type
* @return value associated to key casted to type V
*/
@SuppressWarnings("unchecked")
default V o(K key, Class clazz) {
return (V) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Object. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @param the return type
* @return value associated to key, casted to Object. defaultValue if key is not {@link #valued(Object) valued}
*/
@SuppressWarnings("unchecked")
default V o(K key, V defaultValue) {
return defaultIfMissing(key, defaultValue, this::o);
}
/**
* {@link #get(Object) Gets} given key and transform it using given function. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param transformer a function used to change original value
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @param the return type
* @return value associated to key, tranformed using function. defaultValue if key is not {@link #valued(Object) valued}
*/
default V o(K key, Function transformer, V defaultValue) {
return defaultIfMissing(key, defaultValue, (k) -> o(k, transformer));
}
/**
* {@link #get(Object) Gets} given key and cast it to a Date
*
* @param key the key
* @return value associated to key casted to Date
*/
default Date date(K key) {
return (Date) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Date. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, casted to Date. defaultValue if key is not {@link #valued(Object) valued}
*/
default Date date(K key, Date defaultValue) {
return defaultIfMissing(key, defaultValue, this::date);
}
/**
* A key is valued if {@link #get(Object) get(key)} != null
*
* @param key the key
* @return true if {@link #get(Object) get(key)} != null
*/
default boolean valued(K key) {
return get(key) != null;
}
/**
* Opposite of {@link #valued(Object)}
*
* @param key the key
* @return true if {@link #get(Object) get(key)} == null
*/
default boolean notValued(K key) {
return !valued(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Collection<V>
*
* @param key the key
* @param the return type
* @return value associated to key casted to Collection<V>
*/
@SuppressWarnings("unchecked")
default Collection collection(K key) {
return (Collection) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a Collection<V>. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @param the return type
* @return value associated to key, casted to Collection<V>. defaultValue if key is not {@link #valued(Object) valued}
*/
default Collection collection(K key, Collection defaultValue) {
return defaultIfMissing(key, defaultValue, this::collection);
}
/**
* {@link #get(Object) Gets} given key and cast it to a List<V>
*
* @param key the key
* @param the return type
* @return value associated to key casted to List<V>
*/
@SuppressWarnings("unchecked")
default List list(K key) {
return (List) get(key);
}
/**
* {@link #get(Object) Gets} given key and cast it to a List<V>. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @param the return type
* @return value associated to key, casted to List<V>. defaultValue if key is not {@link #valued(Object) valued}
*/
default List list(K key, List defaultValue) {
return defaultIfMissing(key, defaultValue, this::list);
}
/**
* {@link #get(Object) Gets} given key, cast it to a Collection<V> and returns its Stream<V>
*
* @param key the key
* @param the return type
* @return value associated to key casted to a Collection<V> and converted to a Stream<V>
*/
@SuppressWarnings("unchecked")
default Stream stream(K key) {
return (Stream) collection(key).stream();
}
/**
* {@link #get(Object) Gets} given key, cast it to a Collection<V> and returns its Stream<V>. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @param the return type
* @return value associated to key casted to a Collection<V> and converted to a Stream<V>. defaultValue if key is not {@link #valued(Object) valued}
*/
default Stream stream(K key, Collection defaultValue) {
return collection(key, defaultValue).stream();
}
/**
* Creates a new SteroidMap made of given keys only. Keys must be {@link #valued(Object) valued}
*
* @param keys the keys used to create a new, filtered SteroidMap
* @return a new, filtered, SteroidMap
* @see #subMap(Stream)
*/
default SteroidMap subMap(K... keys) {
return subMap(Stream.of(keys));
}
/**
* Creates a new SteroidMap made of given keys only. Keys must be {@link #valued(Object) valued}
*
* @param keys the keys used to create a new, filtered SteroidMap
* @return a new, filtered, SteroidMap
* @see #subMap(Stream)
*/
default SteroidMap subMap(Collection keys) {
return subMap(keys.stream());
}
/**
* Creates a new SteroidMap made of given keys only. Keys must be {@link #valued(Object) valued}
*
* @param keys the keys used to create a new, filtered SteroidMap
* @return a new, filtered, SteroidMap
*/
SteroidMap subMap(Stream keys);
/**
* Creates a new SteroidMap, backed by given backingMap and made of given keys only. Keys must be {@link #valued(Object) valued}
*
* @param backingMap the actual map to use as storage
* @param keys the keys used to create a new, filtered SteroidMap
* @return a new, filtered, SteroidMap
* @see #subMap(Map, Stream)
*/
default SteroidMap subMap(Map backingMap, K... keys) {
return subMap(backingMap, Stream.of(keys));
}
/**
* Creates a new SteroidMap, backed by given backingMap and made of given keys only. Keys must be {@link #valued(Object) valued}
*
* @param backingMap the actual map to use as storage
* @param keys the keys used to create a new, filtered SteroidMap
* @return a new, filtered, SteroidMap
* @see #subMap(Map, Stream)
*/
default SteroidMap subMap(Map backingMap, Collection keys) {
return subMap(backingMap, keys.stream());
}
/**
* Creates a new SteroidMap, backed by given backingMap and made of given keys only. Keys must be {@link #valued(Object) valued}
*
* @param backingMap the actual map to use as storage
* @param keys the keys used to create a new, filtered SteroidMap
* @return a new, filtered, SteroidMap
*/
SteroidMap subMap(Map backingMap, Stream keys);
/**
* {@link #get(Object) Gets} given key and, if value is not of type SteroidMap, a new SteroidMap is created using value as backing map. Otherwise value is casted to SteroidMap and returned
*
* @param key the key
* @return value associated to key, either casted to SteroidMap or used as backing map for a new SteroidMap
*/
SteroidMap map(K key);
/**
* {@link #get(Object) Gets} given key and, if value is not of type SteroidMap, a new SteroidMap is created using value as backing map. Otherwise value is casted to SteroidMap and returned. If key is not {@link #valued(Object) valued}, it returns defaultValue
*
* @param key the key
* @param defaultValue the defaultValue to return if key is not {@link #valued(Object) valued}
* @return value associated to key, either casted to SteroidMap or used as backing map for a new SteroidMap
*/
default SteroidMap map(K key, SteroidMap defaultValue) {
return defaultIfMissing(key, defaultValue, this::map);
}
/**
* {@link #get(Object) Gets} given key, cast it to a Collection<? extends SteroidMap<K>> and returns its Stream<? extends SteroidMap<K>>. Each entry is evaluated: if it's not of type SteroidMap, a new SteroidMap is created using value as backing map
*
* @param key the key
* @return value associated to key casted to a Collection<? extends SteroidMap<K>> and converted to a Stream<? extends SteroidMap<K>>
*/
default Stream> maps(K key) {
return stream(key).map(this::ensureMapIsOnSteroid);
}
SteroidMap ensureMapIsOnSteroid(Object value);
/**
* Returns a shallow copy of this map
*
* @return a shallow copy of this map
*/
SteroidMap copy();
}