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https://issues.apache.org/jira/browse/LANG-864?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Henri Yandell updated LANG-864:
-------------------------------
Component/s: General
> Collection wrappers to for unmodifiable / nonnull-safe collections
> ------------------------------------------------------------------
>
> Key: LANG-864
> URL: https://issues.apache.org/jira/browse/LANG-864
> Project: Commons Lang
> Issue Type: New Feature
> Components: General
> Reporter: offbynull
> Priority: Minor
>
> Would it be possible to add something like this to commons lang? Commons
> collection looks like it's pretty much dead, and the only alternative for
> this kind of stuff is Google's horribly designed and massively confusing
> Guava library.
> Below are a couple of quick and dirty (untested) examples of the kind of
> wrappers I'm talking about. Note the isLocked/locked methods and the
> viewBlacklist method. Using these methods, it's easy for a component
> receiving a list/set to identify that it's currently unmodifiable and that
> the collection restricts certain values (e.g. null? maybe others?).
> {code}
> public final class LockableBlacklistableList<T> implements List<T> {
> private boolean locked;
> private List<T> list;
> private Set<T> blacklist;
> public LockableBlacklistableList(List<T> backingList, T... blacklist) {
> if (backingList == null) {
> throw new NullPointerException();
> }
> if (!backingList.isEmpty()) {
> throw new IllegalArgumentException();
> }
> this.blacklist = new HashSet<>(Arrays.asList(blacklist));
> this.list = backingList;
> }
> public void lock() {
> locked = true;
> }
> public boolean isLocked() {
> return locked;
> }
> public Set<T> viewBlacklist() {
> return Collections.unmodifiableSet(blacklist);
> }
> @Override
> public int size() {
> return list.size();
> }
> @Override
> public boolean isEmpty() {
> return list.isEmpty();
> }
> @Override
> public boolean contains(Object o) {
> return list.contains(o);
> }
> @Override
> public Iterator<T> iterator() {
> final Iterator<T> it = list.iterator();
> return new Iterator<T>() {
> @Override
> public boolean hasNext() {
> return it.hasNext();
> }
> @Override
> public T next() {
> return it.next();
> }
> @Override
> public void remove() {
> if (locked) {
> throw new IllegalStateException();
> }
> it.remove();
> }
> };
> }
> @Override
> public Object[] toArray() {
> return list.toArray();
> }
> @Override
> public <T> T[] toArray(T[] a) {
> return list.toArray(a);
> }
> @Override
> public boolean add(T e) {
> if (locked) {
> throw new IllegalStateException();
> }
> return list.add(e);
> }
> @Override
> public boolean remove(Object o) {
> if (locked) {
> throw new IllegalStateException();
> }
> return list.remove(o);
> }
> @Override
> public boolean containsAll(Collection<?> c) {
> return list.containsAll(c);
> }
> @Override
> public boolean addAll(Collection<? extends T> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> for (T item : c) {
> if (blacklist.contains(item)) {
> throw new IllegalArgumentException();
> }
> }
> return list.addAll(c);
> }
> @Override
> public boolean addAll(int index, Collection<? extends T> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> for (T item : c) {
> if (blacklist.contains(item)) {
> throw new IllegalArgumentException();
> }
> }
> return list.addAll(index, c);
> }
> @Override
> public boolean removeAll(Collection<?> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> return list.removeAll(c);
> }
> @Override
> public boolean retainAll(Collection<?> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> return list.retainAll(c);
> }
> @Override
> public void clear() {
> if (locked) {
> throw new IllegalStateException();
> }
> list.clear();
> }
> @Override
> public boolean equals(Object o) {
> return list.equals(o);
> }
> @Override
> public int hashCode() {
> return list.hashCode();
> }
> @Override
> public T get(int index) {
> return list.get(index);
> }
> @Override
> public T set(int index, T element) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(element)) {
> throw new IllegalArgumentException();
> }
> return list.set(index, element);
> }
> @Override
> public void add(int index, T element) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(element)) {
> throw new IllegalArgumentException();
> }
> list.add(index, element);
> }
> @Override
> public T remove(int index) {
> if (locked) {
> throw new IllegalStateException();
> }
> return list.remove(index);
> }
> @Override
> public int indexOf(Object o) {
> return list.indexOf(o);
> }
> @Override
> public int lastIndexOf(Object o) {
> return list.lastIndexOf(o);
> }
> @Override
> public ListIterator<T> listIterator() {
> final ListIterator<T> backingListIt = list.listIterator();
> return new ListIterator<T>() {
> @Override
> public boolean hasNext() {
> return backingListIt.hasNext();
> }
> @Override
> public T next() {
> return backingListIt.next();
> }
> @Override
> public boolean hasPrevious() {
> return backingListIt.hasPrevious();
> }
> @Override
> public T previous() {
> return backingListIt.previous();
> }
> @Override
> public int nextIndex() {
> return backingListIt.nextIndex();
> }
> @Override
> public int previousIndex() {
> return backingListIt.previousIndex();
> }
> @Override
> public void remove() {
> if (locked) {
> throw new IllegalStateException();
> }
> backingListIt.remove();
> }
> @Override
> public void set(T e) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(e)) {
> throw new IllegalArgumentException();
> }
> backingListIt.set(e);
> }
> @Override
> public void add(T e) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(e)) {
> throw new IllegalArgumentException();
> }
> backingListIt.add(e);
> }
> };
> }
> @Override
> public ListIterator<T> listIterator(int index) {
> final ListIterator<T> backingListIt = list.listIterator(index);
> return new ListIterator<T>() {
> @Override
> public boolean hasNext() {
> return backingListIt.hasNext();
> }
> @Override
> public T next() {
> return backingListIt.next();
> }
> @Override
> public boolean hasPrevious() {
> return backingListIt.hasPrevious();
> }
> @Override
> public T previous() {
> return backingListIt.previous();
> }
> @Override
> public int nextIndex() {
> return backingListIt.nextIndex();
> }
> @Override
> public int previousIndex() {
> return backingListIt.previousIndex();
> }
> @Override
> public void remove() {
> if (locked) {
> throw new IllegalStateException();
> }
> backingListIt.remove();
> }
> @Override
> public void set(T e) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(e)) {
> throw new IllegalArgumentException();
> }
> backingListIt.set(e);
> }
> @Override
> public void add(T e) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(e)) {
> throw new IllegalArgumentException();
> }
> backingListIt.add(e);
> }
> };
> }
> @Override
> public List<T> subList(int fromIndex, int toIndex) {
> LockableBlacklistableList<T> ret = new LockableBlacklistableList<>(
> list.subList(fromIndex, toIndex));
> ret.locked = locked;
> ret.blacklist = blacklist;
> return ret;
> }
> }
> {code}
> {code}
> public final class LockableBlacklistableSet<T> implements Set<T> {
> private boolean locked;
> private Set<T> set;
> private Set<T> blacklist;
> public LockableBlacklistableSet(Set<T> backingSet, T... blacklist) {
> if (backingSet == null) {
> throw new NullPointerException();
> }
> if (!backingSet.isEmpty()) {
> throw new IllegalArgumentException();
> }
> this.blacklist = new HashSet<>(Arrays.asList(blacklist));
> this.set = backingSet;
> }
>
> public void lock() {
> locked = true;
> }
> public boolean isLocked() {
> return locked;
> }
> public Set<T> viewBlacklist() {
> return Collections.unmodifiableSet(blacklist);
> }
> public int size() {
> return set.size();
> }
> public boolean isEmpty() {
> return set.isEmpty();
> }
> public boolean contains(Object o) {
> return set.contains(o);
> }
> public Iterator<T> iterator() {
> final Iterator<T> it = set.iterator();
> return new Iterator<T>() {
> @Override
> public boolean hasNext() {
> return it.hasNext();
> }
> @Override
> public T next() {
> return it.next();
> }
> @Override
> public void remove() {
> if (locked) {
> throw new IllegalStateException();
> }
> it.remove();
> }
> };
> }
> public Object[] toArray() {
> return set.toArray();
> }
> public <T> T[] toArray(T[] a) {
> return set.toArray(a);
> }
> public boolean add(T e) {
> if (locked) {
> throw new IllegalStateException();
> }
> if (blacklist.contains(item)) {
> throw new IllegalArgumentException();
> }
> return set.add(e);
> }
> public boolean remove(Object o) {
> if (locked) {
> throw new IllegalStateException();
> }
> return set.remove(o);
> }
> public boolean containsAll(Collection<?> c) {
> return set.containsAll(c);
> }
> public boolean addAll(Collection<? extends T> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> for (T item : c) {
> if (blacklist.contains(item)) {
> throw new IllegalArgumentException();
> }
> }
> return set.addAll(c);
> }
> public boolean retainAll(Collection<?> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> return set.retainAll(c);
> }
> public boolean removeAll(Collection<?> c) {
> if (locked) {
> throw new IllegalStateException();
> }
> return set.removeAll(c);
> }
> public void clear() {
> if (locked) {
> throw new IllegalStateException();
> }
> set.clear();
> }
> public boolean equals(Object o) {
> return set.equals(o);
> }
> public int hashCode() {
> return set.hashCode();
> }
> }
> {code}
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