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authorbculkin2442 <bjculkin@mix.wvu.edu>2019-07-02 18:05:22 -0400
committerbculkin2442 <bjculkin@mix.wvu.edu>2019-07-02 18:05:22 -0400
commit843329de434bb334d90927c4d22345373a388530 (patch)
treeb0ad1f764bd29ff43841e1095a5b58194c20cb37 /src/main/java/bjc/data/internals/WrappedOption.java
parentac36f171a3cebb0993cc28548635e3f654f8e325 (diff)
Rename package root
The package root is now bjc, not io.github.bculkin2442.
Diffstat (limited to 'src/main/java/bjc/data/internals/WrappedOption.java')
-rw-r--r--src/main/java/bjc/data/internals/WrappedOption.java96
1 files changed, 96 insertions, 0 deletions
diff --git a/src/main/java/bjc/data/internals/WrappedOption.java b/src/main/java/bjc/data/internals/WrappedOption.java
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+++ b/src/main/java/bjc/data/internals/WrappedOption.java
@@ -0,0 +1,96 @@
+package bjc.data.internals;
+
+import java.util.function.Function;
+import java.util.function.UnaryOperator;
+
+import bjc.data.IHolder;
+import bjc.data.Option;
+
+/**
+ * A wrapped optional value.
+ *
+ * @author Ben Culkin.
+ * @param <ContainedType>
+ * The wrapped type.
+ */
+public class WrappedOption<ContainedType> implements IHolder<ContainedType> {
+ /* The held value. */
+ private final IHolder<IHolder<ContainedType>> held;
+
+ /**
+ * Create a new wrapped option.
+ *
+ * @param seedValue
+ * The value to wrap.
+ */
+ public WrappedOption(final IHolder<ContainedType> seedValue) {
+ held = new Option<>(seedValue);
+ }
+
+ /*
+ * The dummy parameter is to ensure the compiler can pick the right
+ * method, because without this method erases to the same type as the
+ * public one.
+ */
+ private WrappedOption(final IHolder<IHolder<ContainedType>> toHold,
+ @SuppressWarnings("unused") final boolean dummy) {
+ held = toHold;
+ }
+
+ @Override
+ public <BoundType> IHolder<BoundType> bind(final Function<ContainedType, IHolder<BoundType>> binder) {
+ final IHolder<IHolder<BoundType>> newHolder = held.map((containedHolder) -> {
+ return containedHolder.bind((containedValue) -> {
+ if(containedValue == null) return new Option<>(null);
+
+ return binder.apply(containedValue);
+ });
+ });
+
+ return new WrappedOption<>(newHolder, false);
+ }
+
+ @Override
+ public <NewType> Function<ContainedType, IHolder<NewType>> lift(final Function<ContainedType, NewType> func) {
+ return (val) -> {
+ return new Option<>(func.apply(val));
+ };
+ }
+
+ @Override
+ public <MappedType> IHolder<MappedType> map(final Function<ContainedType, MappedType> mapper) {
+ final IHolder<IHolder<MappedType>> newHolder = held.map((containedHolder) -> {
+ return containedHolder.map((containedValue) -> {
+ if(containedValue == null) return null;
+
+ return mapper.apply(containedValue);
+ });
+ });
+
+ return new WrappedOption<>(newHolder, false);
+ }
+
+ @Override
+ public IHolder<ContainedType> transform(final UnaryOperator<ContainedType> transformer) {
+ held.transform((containedHolder) -> {
+ return containedHolder.transform((containedValue) -> {
+ if(containedValue == null) return null;
+
+ return transformer.apply(containedValue);
+ });
+ });
+
+ return this;
+ }
+
+ @Override
+ public <UnwrappedType> UnwrappedType unwrap(final Function<ContainedType, UnwrappedType> unwrapper) {
+ return held.unwrap((containedHolder) -> {
+ return containedHolder.unwrap((containedValue) -> {
+ if(containedValue == null) return null;
+
+ return unwrapper.apply(containedValue);
+ });
+ });
+ }
+}