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fix issues with Lab5

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This commit is contained in:
Yadunand Prem
2022-10-13 14:13:12 +08:00
parent e1320e2a52
commit 82a1f769fe
1 changed files with 13 additions and 11 deletions
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24
Lab5/cs2030s/fp/Actually.java
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@@ -7,8 +7,8 @@ public abstract class Actually<T> implements Immutatorable<T>, Actionable<T> {
} }
public static <T> Actually<T> err(Exception e) { public static <T> Actually<T> err(Exception e) {
// It is okay to do an unchecked cast here as failure types don't use // It is okay to do an unchecked cast here as failure types don't use
// the value T. // the value T.
@SuppressWarnings("unchecked") @SuppressWarnings("unchecked")
Actually<T> failure = (Actually<T>) new Failure(e); Actually<T> failure = (Actually<T>) new Failure(e);
return failure; return failure;
@@ -20,10 +20,9 @@ public abstract class Actually<T> implements Immutatorable<T>, Actionable<T> {
public abstract void finish(Action<? super T> action); public abstract void finish(Action<? super T> action);
public abstract T unless(T other); public abstract <U extends T> T unless(U other);
public abstract <R> Actually<R> next(Immutator<Actually<R>, ? super T> immutator);
public abstract <R> Actually<R> next(Immutator<? extends Actually<? extends R>, ? super T> immutator);
private static class Success<T> extends Actually<T> { private static class Success<T> extends Actually<T> {
private final T value; private final T value;
@@ -48,21 +47,24 @@ public abstract class Actually<T> implements Immutatorable<T>, Actionable<T> {
} }
@Override @Override
public T unless(T other) { public <U extends T> T unless(U other) {
return this.value; return this.value;
} }
@Override @Override
public <R> Actually<R> next(Immutator<Actually<R>, ? super T> immutator) { public <R> Actually<R> next(Immutator<? extends Actually<? extends R>, ? super T> immutator) {
try { try {
return immutator.invoke(this.value); // it is okay to cast from <? extends R> to <R>
@SuppressWarnings("unchecked")
Actually<R> result = (Actually<R>) immutator.invoke(this.value);
return result;
} catch (Exception e) { } catch (Exception e) {
return Actually.err(e); return Actually.err(e);
} }
} }
@Override @Override
public <R> Immutatorable<R> transform(Immutator<? extends R, ? super T> immutator) { public <R> Actually<R> transform(Immutator<? extends R, ? super T> immutator) {
try { try {
return Actually.ok(immutator.invoke(this.value)); return Actually.ok(immutator.invoke(this.value));
} catch (Exception e) { } catch (Exception e) {
@@ -127,12 +129,12 @@ public abstract class Actually<T> implements Immutatorable<T>, Actionable<T> {
} }
@Override @Override
public <R> Immutatorable<R> transform(Immutator<? extends R, ? super Object> immutator) { public <R> Actually<R> transform(Immutator<? extends R, ? super Object> immutator) {
return Actually.err(this.e); return Actually.err(this.e);
} }
@Override @Override
public <R> Actually<R> next(Immutator<Actually<R>, ? super Object> immutator) { public <R> Actually<R> next(Immutator<? extends Actually<? extends R>, ? super Object> immutator) {
return Actually.err(this.e); return Actually.err(this.e);
} }