com.cedarsoftware.util.SealableNavigableSet Maven / Gradle / Ivy
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package com.cedarsoftware.util;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.NavigableSet;
import java.util.SortedSet;
import java.util.function.Supplier;
/**
* SealableNavigableSet provides a NavigableSet or NavigableSet wrapper that can be 'sealed' and
* 'unsealed.' When sealed, the NavigableSet is mutable, when unsealed it is immutable (read-only).
* The view methods iterator(), descendingIterator(), descendingSet(), subSet(), headSet(), and
* tailSet(), return a view that honors the Supplier's sealed state. The sealed state can be
* changed as often as needed.
*
* NOTE: Please do not reformat this code as the current format makes it easy to see the overall structure.
*
* @author John DeRegnaucourt
*
* Copyright (c) Cedar Software LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* License
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
public class SealableNavigableSet implements NavigableSet {
private final NavigableSet navSet;
private final transient Supplier sealedSupplier;
/**
* Create a NavigableSealableSet. Since a NavigableSet is not supplied, this will use a ConcurrentSkipListSet
* internally. If you want to use a TreeSet for example, use the SealableNavigableSet constructor that takes
* a NavigableSet and pass it the instance you want it to wrap.
* @param sealedSupplier {@code Supplier} that returns 'true' to indicate sealed, 'false' for mutable.
*/
public SealableNavigableSet(Supplier sealedSupplier) {
this.sealedSupplier = sealedSupplier;
navSet = new ConcurrentNavigableSetNullSafe<>();
}
/**
* Create a NavigableSealableSet. Since a NavigableSet is not supplied, this will use a ConcurrentSkipListSet
* internally. If you want to use a TreeSet for example, use the SealableNavigableSet constructor that takes
* a NavigableSet and pass it the instance you want it to wrap.
* @param comparator {@code Comparator} A comparison function, which imposes a total ordering on some
* collection of objects.
* @param sealedSupplier {@code Supplier} that returns 'true' to indicate sealed, 'false' for mutable.
*/
public SealableNavigableSet(Comparator comparator, Supplier sealedSupplier) {
this.sealedSupplier = sealedSupplier;
navSet = new ConcurrentNavigableSetNullSafe<>(comparator);
}
/**
* Create a NavigableSealableSet. Since NavigableSet is not supplied, the elements from the passed in Collection
* will be copied to an internal ConcurrentSkipListSet. If you want to use a TreeSet for example, use the
* SealableNavigableSet constructor that takes a NavigableSet and pass it the instance you want it to wrap.
* @param col Collection to supply initial elements. These are copied to an internal ConcurrentSkipListSet.
* @param sealedSupplier {@code Supplier} that returns 'true' to indicate sealed, 'false' for mutable.
*/
public SealableNavigableSet(Collection col, Supplier sealedSupplier) {
this(sealedSupplier);
addAll(col);
}
/**
* Create a NavigableSealableSet. Since NavigableSet is not supplied, the elements from the passed in SortedSet
* will be copied to an internal ConcurrentSkipListSet. If you want to use a TreeSet for example, use the
* SealableNavigableSet constructor that takes a NavigableSet and pass it the instance you want it to wrap.
* @param set SortedSet to supply initial elements. These are copied to an internal ConcurrentSkipListSet.
* @param sealedSupplier {@code Supplier} that returns 'true' to indicate sealed, 'false' for mutable.
*/
public SealableNavigableSet(SortedSet set, Supplier sealedSupplier) {
this.sealedSupplier = sealedSupplier;
navSet = new ConcurrentNavigableSetNullSafe<>(set);
}
/**
* Use this constructor to wrap a NavigableSet (any kind of NavigableSet) and make it a SealableNavigableSet.
* No duplicate of the Set is created, the original set is operated on directly if unsealed, or protected
* from changes if sealed.
* @param set NavigableSet instance to protect.
* @param sealedSupplier {@code Supplier} that returns 'true' to indicate sealed, 'false' for mutable.
*/
public SealableNavigableSet(NavigableSet set, Supplier sealedSupplier) {
this.sealedSupplier = sealedSupplier;
navSet = set;
}
private void throwIfSealed() {
if (sealedSupplier.get()) {
throw new UnsupportedOperationException("This set has been sealed and is now immutable");
}
}
// Immutable APIs
public boolean equals(Object o) { return o == this || navSet.equals(o); }
public int hashCode() { return navSet.hashCode(); }
public String toString() { return navSet.toString(); }
public int size() { return navSet.size(); }
public boolean isEmpty() { return navSet.isEmpty(); }
public boolean contains(Object o) { return navSet.contains(o); }
public boolean containsAll(Collection col) { return navSet.containsAll(col);}
public Comparator comparator() { return navSet.comparator(); }
public E first() { return navSet.first(); }
public E last() { return navSet.last(); }
public Object[] toArray() { return navSet.toArray(); }
public T1[] toArray(T1[] a) { return navSet.toArray(a); }
public E lower(E e) { return navSet.lower(e); }
public E floor(E e) { return navSet.floor(e); }
public E ceiling(E e) { return navSet.ceiling(e); }
public E higher(E e) { return navSet.higher(e); }
public Iterator iterator() {
return createSealHonoringIterator(navSet.iterator());
}
public Iterator descendingIterator() {
return createSealHonoringIterator(navSet.descendingIterator());
}
public NavigableSet descendingSet() {
return new SealableNavigableSet<>(navSet.descendingSet(), sealedSupplier);
}
public SortedSet subSet(E fromElement, E toElement) {
return subSet(fromElement, true, toElement, false);
}
public NavigableSet subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
return new SealableNavigableSet<>(navSet.subSet(fromElement, fromInclusive, toElement, toInclusive), sealedSupplier);
}
public SortedSet headSet(E toElement) {
return headSet(toElement, false);
}
public NavigableSet headSet(E toElement, boolean inclusive) {
return new SealableNavigableSet<>(navSet.headSet(toElement, inclusive), sealedSupplier);
}
public SortedSet tailSet(E fromElement) {
return tailSet(fromElement, false);
}
public NavigableSet tailSet(E fromElement, boolean inclusive) {
return new SealableNavigableSet<>(navSet.tailSet(fromElement, inclusive), sealedSupplier);
}
// Mutable APIs
public boolean add(E e) { throwIfSealed(); return navSet.add(e); }
public boolean addAll(Collection col) { throwIfSealed(); return navSet.addAll(col); }
public void clear() { throwIfSealed(); navSet.clear(); }
public boolean remove(Object o) { throwIfSealed(); return navSet.remove(o); }
public boolean removeAll(Collection col) { throwIfSealed(); return navSet.removeAll(col); }
public boolean retainAll(Collection col) { throwIfSealed(); return navSet.retainAll(col); }
public E pollFirst() { throwIfSealed(); return navSet.pollFirst(); }
public E pollLast() { throwIfSealed(); return navSet.pollLast(); }
private Iterator createSealHonoringIterator(Iterator iterator) {
return new Iterator() {
public boolean hasNext() { return iterator.hasNext(); }
public E next() {
E item = iterator.next();
if (item instanceof Map.Entry) {
Map.Entry entry = (Map.Entry) item;
return (E) new SealableSet.SealAwareEntry<>(entry, sealedSupplier);
}
return item;
}
public void remove() { throwIfSealed(); iterator.remove();}
};
}
}