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Public API for the Structure Plugin for JIRA
package com.almworks.jira.structure.api.util;
import com.almworks.integers.*;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.lang.reflect.Array;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Function;
import java.util.function.Predicate;
/**
* La is a utility generic-purpose class for functional expressions.
*
* @author Igor Sereda
*/
public abstract class La implements Function, Predicate {
private static final La SELF = new La() {
public Object la(Object argument) {
return argument;
}
};
private static final La TRUE = new La() {
public Object la(Object argument) {
return Boolean.TRUE;
}
};
private static final La FALSE = new La() {
public Object la(Object argument) {
return Boolean.FALSE;
}
};
private static final La NOT_NULL = new La() {
public Boolean la(Object argument) {
return argument != null;
}
};
private static final La TO_STRING = new La(String.class) {
@Override
public String la(Object argument) {
return argument == null ? null : argument.toString();
}
};
private final Class rClass;
protected La() {
rClass = null;
}
/**
* Use this constructor to have class-aware instance, which is needed only for
* few methods like {@link #array}.
*
* @param rClass the class of the result
*/
protected La(Class rClass) {
this.rClass = rClass;
}
public abstract R la(T argument);
// ============== constructors ================
@NotNull
public static La adapt(final Function f) {
if (f == null) throw new NullPointerException();
return new La() {
@Override
public R la(T argument) {
return f.apply(argument);
}
};
}
@NotNull
public static La constant(final R result) {
if (result == Boolean.TRUE) return (La) TRUE;
if (result == Boolean.FALSE) return (La) FALSE;
return new La() {
public R la(T argument) {
return result;
}
};
}
public static La constantFalse() {
return (La)FALSE;
}
public static La constantTrue() {
return (La)TRUE;
}
@NotNull
public static La isEqual(@Nullable final T value) {
final boolean isNull = value == null;
return new La() {
public Boolean la(T argument) {
return isNull ? argument == null : value.equals(argument);
}
};
}
// we could declare the parameter as Collection, but then we'd lose type inference for the calling line
@NotNull
public static La inCollection(@Nullable final Collection collection) {
if (collection == null) return constant(false);
return new La() {
public Boolean la(T argument) {
return collection.contains(argument);
}
};
}
@NotNull
public static La instanceOf(@Nullable final Class instanceClass) {
if (instanceClass == null) return constant(false);
return new La() {
public Boolean la(T argument) {
return instanceClass.isInstance(argument);
}
};
}
@NotNull
public static La cast(@Nullable Class clazz) {
if (clazz == null) return constant(null);
return new La() {
@Override
public T la(Object argument) {
return clazz.isInstance(argument) ? clazz.cast(argument) : null;
}
};
}
@NotNull
public static La compose(final La g, final La f) {
if (f == null) throw new NullPointerException();
if (g == null) throw new NullPointerException();
return new La(g.rClass) {
public C la(A argument) {
return g.la(f.la(argument));
}
};
}
@NotNull
@SuppressWarnings("unchecked")
public static La self() {
return (La) SELF;
}
@NotNull
public static La fromMap(final Map map, Class rClass) {
if (map == null) throw new NullPointerException();
return new La(rClass) {
@Override
public R la(T argument) {
return map.get(argument);
}
};
}
// ============== utilities ================
@Override
public final R apply(T from) {
return la(from);
}
@Override
public boolean test(T input) {
return accepts(input);
}
@NotNull
public La apply(final La f) {
return compose(this, f);
}
@NotNull
public La supply(final La g) {
return compose(g, this);
}
@NotNull
public ArrayList filter(@Nullable Iterable collection) {
ArrayList r = new ArrayList<>();
if (collection != null) {
for (D item : collection) {
if (accepts(item)) {
r.add(item);
}
}
}
return r;
}
@NotNull
public Iterator filter(@Nullable Iterator iterator) {
return iterator == null ? Collections.emptyIterator() : new FilterIterator<>(iterator);
}
@NotNull
public Iterable filterIterable(@Nullable final Iterable iterable) {
if (iterable == null) {
return Collections.emptyList();
}
return () -> new FilterIterator<>(iterable.iterator());
}
public boolean accepts(T value) {
return acceptsResult(la(value));
}
private boolean acceptsResult(R value) {
return value != null && !value.equals(false) && !value.equals(0) && !value.equals(0L);
}
@NotNull
public HashSet hashSet(@Nullable Collection from) {
if (from == null) return new HashSet<>();
return addTo(from, new HashSet<>(from.size()), true);
}
@NotNull
public LinkedHashSet linkedHashSet(@Nullable Collection from) {
if (from == null) return new LinkedHashSet<>();
return addTo(from, new LinkedHashSet<>(from.size()), true);
}
@NotNull
public List arrayList(@Nullable T ... from) {
return from == null || from.length == 0 ? Collections.emptyList() : arrayList(Arrays.asList(from));
}
public List arrayList(@Nullable Collection from) {
return arrayList(from, true);
}
@NotNull
public Iterable iterable(@Nullable final Iterable from) {
return () -> La.this.iterator(from);
}
@NotNull
public Iterator iterator(Iterable from) {
final Iterator source = from == null ? null : from.iterator();
if (source == null) return Collections.emptyIterator();
return new Iterator() {
public boolean hasNext() {
return source.hasNext();
}
public R next() {
return la(source.next());
}
public void remove() {
source.remove();
}
};
}
@NotNull
public List arrayList(@Nullable Collection from, boolean acceptFalsy) {
if (from == null) return new ArrayList<>();
return addTo(from, new ArrayList<>(from.size()), acceptFalsy);
}
public List arrayList(@Nullable Iterator from) {
return arrayList(from, true);
}
public List arrayList(@Nullable Iterator from, boolean acceptFalsy) {
if (from == null) return new ArrayList<>();
return addTo(from, new ArrayList<>(), acceptFalsy);
}
@NotNull
public static LongList longList(@Nullable Collection collection, @NotNull La la) {
if (collection == null || collection.isEmpty()) {
return LongList.EMPTY;
}
LongArray result = new LongArray(collection.size());
for (T element : collection) {
Long value = la.la(element);
if (value != null && value > 0) {
result.add(value);
}
}
return result;
}
@NotNull
public static IntList intList(@Nullable Collection collection, @NotNull La la) {
if (collection == null || collection.isEmpty()) {
return IntList.EMPTY;
}
IntArray result = new IntArray(collection.size());
for (T element : collection) {
Integer value = la.la(element);
if (value != null && value > 0) {
result.add(value);
}
}
return result;
}
@NotNull
public > C addTo(@Nullable Collection from, @NotNull C to, boolean acceptFalsy) {
if (from != null) {
addTo(from.iterator(), to, acceptFalsy);
}
return to;
}
@NotNull
public > C addTo(@Nullable Iterator from, @NotNull C to, boolean acceptFalsy) {
if (from != null) {
while (from.hasNext()) {
T t = from.next();
R r = la(t);
if (acceptFalsy || acceptsResult(r)) {
to.add(r);
}
}
}
return to;
}
public Iterator transform(Iterator iterator) {
return new TransformIterator<>(iterator);
}
public Iterable transformIterable(final Iterable iterable) {
return () -> new TransformIterator<>(iterable.iterator());
}
@NotNull
public R[] array(@Nullable Collection from) {
return array(from, true);
}
@NotNull
public R[] array(@Nullable Collection from, boolean acceptFalsy) {
Class cls = rClass;
if (cls == null) {
throw new UnsupportedOperationException("cannot create array without rClass (" + from + ")");
}
R[] result = (R[]) Array.newInstance(cls, from == null ? 0 : from.size());
if (from != null) {
int i = 0;
for (T t : from) {
if (i >= result.length) {
throw new IllegalStateException("collection changed on the go");
}
R r = la(t);
if (acceptFalsy || acceptsResult(r)) {
result[i++] = r;
}
}
if (i < result.length) {
result = Arrays.copyOf(result, i);
}
}
return result;
}
@NotNull
public Map mapInto(@Nullable Collection fromCollection, @NotNull Map toMap) {
return mapInto(fromCollection, toMap, La.self());
}
@NotNull
public Map mapInto(@Nullable Collection fromCollection, @NotNull Map toMap, @NotNull La valueFunction) {
if (fromCollection != null) {
for (C value : fromCollection) {
R key = la(value);
if (key != null) {
toMap.put(key, valueFunction.la(value));
}
}
}
return toMap;
}
@NotNull
public Map hashMap(@Nullable Collection collection) {
return hashMap(collection, La.self());
}
@NotNull
public Map hashMap(@Nullable Collection collection, @NotNull La valueFunction) {
HashMap map = new HashMap<>(collection == null ? 0 : collection.size());
return mapInto(collection, map, valueFunction);
}
@NotNull
public Map linkedHashMap(@Nullable Collection collection, @NotNull La valueFunction) {
LinkedHashMap map = new LinkedHashMap<>(collection == null ? 0 : collection.size());
return mapInto(collection, map, valueFunction);
}
public int indexOf(@Nullable List list, R sample) {
if (list == null) return -1;
for (int i = 0; i < list.size(); i++) {
R v = la(list.get(i));
if (sample == null && v == null || sample != null && sample.equals(v)) return i;
}
return -1;
}
public int lastIndexOf(@Nullable List list, R sample) {
if (list == null) return -1;
for (int i = list.size() - 1; i >= 0; --i) {
R v = la(list.get(i));
if (sample == null && v == null || sample != null && sample.equals(v)) return i;
}
return -1;
}
@Nullable
public X find(@Nullable Collection collection, R sample) {
if (collection == null || collection.isEmpty()) return null;
for (X value : collection) {
R r = la(value);
if (r == null && sample == null) {
return value;
} else if (r != null && r.equals(sample)) {
return value;
}
}
return null;
}
public boolean any(@Nullable Iterable sequence) {
if (sequence == null) return false;
for (T value : sequence) if (accepts(value)) return true;
return false;
}
@NotNull
public La not() {
final La positive = this;
return new La() {
public Boolean la(T argument) {
return !positive.accepts(argument);
}
};
}
public La and(final La second) {
final La first = this;
return new La() {
public Boolean la(T argument) {
return first.accepts(argument) && second.accepts(argument);
}
};
}
public La memoize() {
final La delegate = this;
final Map map = new HashMap<>();
return new La() {
@Override
public R la(T argument) {
R result = map.get(argument);
if (result == null && !map.containsKey(argument)) {
result = delegate.la(argument);
map.put(argument, result);
}
return result;
}
};
}
public La memoizeConcurrent() {
final La delegate = this;
final ConcurrentMap map = new ConcurrentHashMap<>();
return new La() {
@Override
public R la(T argument) {
assert argument != null;
R result = map.get(argument);
if (result == null) {
result = delegate.la(argument);
assert result != null;
map.putIfAbsent(argument, result);
}
return result;
}
};
}
public Comparator comparator(Comparator comparator) {
return new LaComparator<>(this, comparator);
}
public static > Comparator comparator(La function) {
return function.comparator(new ComparableComparator<>());
}
public > La> liftToList() {
final La transform = this;
return new La>() {
@Override
public List la(C argument) {
if (argument == null) {
return null;
}
Iterator it = argument.iterator();
if (it.hasNext()) {
return transform.arrayList(it);
} else {
return Collections.emptyList();
}
}
};
}
public static La notNull() {
return NOT_NULL;
}
public static La stringValue() {
return TO_STRING;
}
public static La notNull(final La la, final B onNull) {
return new La(la.rClass) {
@Override
public B la(A argument) {
B result = la.la(argument);
return result == null ? onNull : result;
}
};
}
public Collection image(Collection set) {
return image(set, false);
}
private Collection image(final Collection set, final boolean includeFalsy) {
if (set == null) return Collections.emptyList();
return new AbstractCollection() {
@NotNull
public Iterator iterator() {
Iterator it = transform(set.iterator());
if (!includeFalsy) {
it = La.self().filter(it);
}
return it;
}
public int size() {
if (includeFalsy) {
return set.size();
}
int count = 0;
for (T v : set) {
if (accepts(v)) {
count++;
}
}
return count;
}
};
}
public static class LaComparator implements Comparator {
private final La myFunction;
private final Comparator myComparator;
public LaComparator(La function, Comparator comparator) {
if (function == null) {
throw new IllegalArgumentException("function is null");
}
if (comparator == null) {
throw new IllegalArgumentException("comparator is null");
}
myFunction = function;
myComparator = comparator;
}
@Override
public int compare(A o1, A o2) {
B b1 = myFunction.apply(o1);
B b2 = myFunction.apply(o2);
return myComparator.compare(b1, b2);
}
}
public static class ComparableComparator> implements Comparator {
@Override
public int compare(B b1, B b2) {
if (b1 == null) {
return b2 == null ? 0 : -1;
}
if (b2 == null) {
return 1;
}
return b1.compareTo(b2);
}
}
public class FilterIterator implements Iterator {
private final Iterator myOuter;
private Boolean hasNext = null;
private D next;
public FilterIterator(Iterator iterator) {
myOuter = iterator;
}
@Override
public boolean hasNext() {
if (hasNext == null) {
hasNext = calcHasNext();
}
return hasNext;
}
private boolean calcHasNext() {
while (myOuter.hasNext()) {
next = myOuter.next();
if (accepts(next)) return true;
}
return false;
}
@Override
public D next() {
if (!hasNext())
throw new NoSuchElementException();
hasNext = null;
return next;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
public class TransformIterator implements Iterator {
private final Iterator mySourceIterator;
public TransformIterator(Iterator iterator) {
mySourceIterator = iterator;
}
@Override
public boolean hasNext() {
return mySourceIterator.hasNext();
}
@Override
public R next() {
return la(mySourceIterator.next());
}
@Override
public void remove() {
mySourceIterator.remove();
}
}
}
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