1 files changed, 116 insertions, 0 deletions
diff --git a/src/main/java/bjc/funcdata/TransformedValueMap.java b/src/main/java/bjc/funcdata/TransformedValueMap.java
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index 0000000..0f0b3b5
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+++ b/src/main/java/bjc/funcdata/TransformedValueMap.java
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+package bjc.funcdata;
+
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+/**
+ * A map that transforms values from one type to another
+ *
+ * @author ben
+ *
+ * @param <OldKey>
+ *        The type of the map's keys
+ *
+ * @param <OldValue>
+ *        The type of the map's values
+ *
+ * @param <NewValue>
+ *        The type of the transformed values
+ *
+ */
+final class TransformedValueMap<OldKey, OldValue, NewValue> implements IMap<OldKey, NewValue> {
+	/* Our backing map. */
+	private final IMap<OldKey, OldValue> backing;
+	/* Our transforming function. */
+	private final Function<OldValue, NewValue> transformer;
+
+	/**
+	 * Create a new transformed-value loop.
+	 *
+	 * @param backingMap
+	 *        The map to use as backing.
+	 *
+	 * @param transform
+	 *        The function to use for the transform.
+	 */
+	public TransformedValueMap(final IMap<OldKey, OldValue> backingMap,
+			final Function<OldValue, NewValue> transform) {
+		backing = backingMap;
+		transformer = transform;
+	}
+
+	@Override
+	public void clear() {
+		backing.clear();
+	}
+
+	@Override
+	public boolean containsKey(final OldKey key) {
+		return backing.containsKey(key);
+	}
+
+	@Override
+	public IMap<OldKey, NewValue> extend() {
+		return new ExtendedMap<>(this, new FunctionalMap<>());
+	}
+
+	@Override
+	public void forEach(final BiConsumer<OldKey, NewValue> action) {
+		backing.forEach((key, value) -> {
+			action.accept(key, transformer.apply(value));
+		});
+	}
+
+	@Override
+	public void forEachKey(final Consumer<OldKey> action) {
+		backing.forEachKey(action);
+	}
+
+	@Override
+	public void forEachValue(final Consumer<NewValue> action) {
+		backing.forEachValue(value -> {
+			action.accept(transformer.apply(value));
+		});
+	}
+
+	@Override
+	public NewValue get(final OldKey key) {
+		return transformer.apply(backing.get(key));
+	}
+
+	@Override
+	public int size() {
+		return backing.size();
+	}
+
+	@Override
+	public IList<OldKey> keyList() {
+		return backing.keyList();
+	}
+
+	@Override
+	public <MappedValue> IMap<OldKey, MappedValue> transform(final Function<NewValue, MappedValue> transform) {
+		return new TransformedValueMap<>(this, transform);
+	}
+
+	@Override
+	public NewValue put(final OldKey key, final NewValue value) {
+		throw new UnsupportedOperationException("Can't add items to transformed map");
+	}
+
+	@Override
+	public NewValue remove(final OldKey key) {
+		return transformer.apply(backing.remove(key));
+	}
+
+	@Override
+	public String toString() {
+		return backing.toString();
+	}
+
+	@Override
+	public IList<NewValue> valueList() {
+		return backing.valueList().map(transformer);
+	}
+}