org.apache.jackrabbit.oak.security.internal.Preconditions Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
*/
package org.apache.jackrabbit.oak.security.internal;
import java.util.Set;
import static com.google.common.collect.Sets.newHashSet;
/**
* Represents a preconditions set that may be satisfied by adding the right
* candidates.
*
* Initially, a set of preconditions is empty. An empty set of preconditions is
* always satisfied. If candidates are added, but the precondition set is empty,
* the preconditions are considered satisfied.
*
* When some preconditions are added, the preconditions set may enter into the
* unsatisfied state. In this case, the preconditions set may be come satisfied
* again only with the addition of the right candidates.
*
* This class doesn't admit duplicates for preconditions or candidates. Adding
* the same precondition (or candidate) twice doesn't have any effect on the
* state of the preconditions set.
*/
class Preconditions {
private final Set preconditions = newHashSet();
private final Set candidates = newHashSet();
private boolean dirty = false;
private boolean satisfied = true;
/**
* Add a precondition to this preconditions set. If the precondition already
* belongs to this set, this operation has no effect.
*
* @param precondition The precondition to be added.
*/
public void addPrecondition(String precondition) {
if (preconditions.add(precondition)) {
dirty = true;
}
}
/**
* Remove all the preconditions to this set. This makes the set of
* preconditions empty and, as such, satisfied.
*/
public void clearPreconditions() {
preconditions.clear();
dirty = false;
satisfied = true;
}
/**
* Add a candidate to this preconditions set. If the candidate already
* belongs to this set, this operation has no effect.
*
* @param candidate The candidate to be added.
*/
public void addCandidate(String candidate) {
if (candidates.add(candidate)) {
dirty = true;
}
}
/**
* Remove a candidate from this preconditions set. If the candidate doesn't
* belong to this set, this operation has no effect.
*
* @param candidate The candidate to be removed.
*/
public void removeCandidate(String candidate) {
if (candidates.remove(candidate)) {
dirty = true;
}
}
/**
* Check if the preconditions set are satisfied.
*
* @return {@code true} if the preconditions set is satisfied, {@code false}
* otherwise.
*/
public boolean areSatisfied() {
if (dirty) {
satisfied = candidates.containsAll(preconditions);
dirty = false;
}
return satisfied;
}
@Override
public String toString() {
return String.format("Preconditions(preconditions = %s, candidates = %s)", preconditions, candidates);
}
}