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/*-
* #%L
* org.sputnikdev:bluetooth-manager
* %%
* Copyright (C) 2017 Sputnik Dev
* %%
* 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
*
* 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.
* #L%
*/
package org.sputnikdev.bluetooth.manager.impl;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicLong;
/**
* A utility class that can accommodate 63 boolean flags. It is similar to {@link java.util.BitSet}
* but synchronized and provides some "atomic" utility methods for tracking changes.
* @author Vlad Kolotov
*/
class ConcurrentBitMap {
private final AtomicLong bits = new AtomicLong();
private final Queue notifications = new ConcurrentLinkedQueue<>();
/**
* Sets a new cumulative state for the bitmap field.
* @param index index of the new state
* @param newState value of the new state
*/
void cumulativeSet(int index, boolean newState) {
cumulativeSet(index, newState, null, null);
}
/**
* Sets a new cumulative state for the bitmap field.
* @param index index of the new state
* @param newState value of the new state
* @param changed triggered if the overall state changes
*/
void cumulativeSet(int index, boolean newState, Runnable changed) {
cumulativeSet(index, newState, changed, null);
}
/**
* Sets a new exclusive state for the bitmap field.
* @param index index of the new state
* @param newState value of the new state
*/
void exclusiveSet(int index, boolean newState) {
exclusiveSet(index, newState, null, null);
}
/**
* Sets a new exclusive state for the bitmap field.
* @param index index of the new state
* @param newState value of the new state
* @param changed triggered if the overall state changes
*/
void exclusiveSet(int index, boolean newState, Runnable changed) {
exclusiveSet(index, newState, changed, null);
}
/**
* Sets a new cumulative state for the bitmap field.
* @param index index of the new state
* @param newState value of the new state
* @param changed triggered if the overall state changes
* @param notChanged triggered if the overall state does not change
*/
void cumulativeSet(int index, boolean newState, Runnable changed, Runnable notChanged) {
if (index < 0 || index > 63) {
throw new IllegalStateException("Invalid index, must be between 0 and 63: " + index);
}
bits.getAndUpdate(current -> {
long updated = newState ? current | (1L << index) : current & ~(1L << index);
if (updated > 0 && current == 0 || updated == 0 && current > 0) {
if (changed != null) {
notifications.add(changed);
}
} else if (notChanged != null) {
notifications.add(notChanged);
}
return updated;
});
handleNotifications();
}
/**
* Sets a new exclusive state for the bitmap field.
* @param index index of the new state
* @param newState value of the new state
* @param changed triggered if the overall state changes
* @param notChanged triggered if the overall state does not change
*/
void exclusiveSet(int index, boolean newState, Runnable changed, Runnable notChanged) {
if (index < 0 || index > 63) {
throw new IllegalStateException("Invalid index, must be between 0 and 63: " + index);
}
bits.getAndUpdate(current -> {
long updated = newState ? (1L << index) : current & ~(1L << index);
if (updated > 0 && current == 0 || updated == 0 && current > 0) {
if (changed != null) {
notifications.add(changed);
}
} else if (notChanged != null) {
notifications.add(notChanged);
}
return updated;
});
handleNotifications();
}
/**
* Returns cumulative value (if any of bits is set to 1).
* @return true if any of bits is set to 1, false otherwise
*/
boolean get() {
return bits.get() > 0;
}
/**
* Returns the one bit index. If multiple one bits found, an IllegalStateException is thrown.
* If no one bits found, -1 returned.
* @return one bit index
*/
int getUniqueIndex() {
long state = bits.get();
if (Long.bitCount(state) > 1) {
throw new IllegalStateException("Multiple one bits found");
}
return Long.numberOfTrailingZeros(state);
}
private void handleNotifications() {
notifications.removeIf(notification -> {
notification.run();
return true;
});
}
}
