/hazelcast/src/main/java/com/hazelcast/impl/base/DistributedSemaphore.java
https://bitbucket.org/gabral6_gmailcom/hazelcast · Java · 124 lines · 90 code · 19 blank · 15 comment · 15 complexity · 41e657dbacd292d7a5402eb00d01c19b MD5 · raw file
- /*
- * Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
- *
- * 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.
- */
- package com.hazelcast.impl.base;
- import com.hazelcast.nio.Address;
- import com.hazelcast.nio.DataSerializable;
- import java.io.DataInput;
- import java.io.DataOutput;
- import java.io.IOException;
- import java.util.HashMap;
- import java.util.Map;
- public class DistributedSemaphore implements DataSerializable {
- Map<Address, Integer> attachedPermits = new HashMap<Address, Integer>();
- int available;
- public DistributedSemaphore() {
- }
- public DistributedSemaphore(int initialPermits) {
- available = initialPermits;
- }
- public void readData(DataInput in) throws IOException {
- Address address;
- attachedPermits.clear();
- available = in.readInt();
- int entries = in.readInt();
- while (entries-- > 0) {
- (address = new Address()).readData(in);
- attachedPermits.put(address, in.readInt());
- }
- }
- public void writeData(DataOutput out) throws IOException {
- out.writeInt(available);
- out.writeInt(attachedPermits.size());
- for (Map.Entry<Address, Integer> entry : attachedPermits.entrySet()) {
- entry.getKey().writeData(out);
- out.writeInt(entry.getValue());
- }
- }
- public void attachDetach(Integer permitsDelta, Address address) {
- if (permitsDelta != 0 && address != null) {
- int newValue = permitsDelta + getAttached(address);
- if (newValue != 0) {
- attachedPermits.put(address, newValue);
- } else {
- attachedPermits.remove(address);
- }
- }
- }
- public int drain() {
- int drained = available;
- available = 0;
- return drained;
- }
- public int getAttached() {
- int total = 0;
- for (Integer permits : attachedPermits.values()) {
- total += permits;
- }
- return total;
- }
- public int getAttached(Address address) {
- return attachedPermits.containsKey(address) ? attachedPermits.get(address) : 0;
- }
- public int getAvailable() {
- return available;
- }
- public void reduce(int permits) {
- available -= permits;
- }
- public void release(int permits, Address address) {
- available += permits;
- attachDetach(permits, address);
- }
- public boolean tryAcquire(int permits, Address address) {
- if (available >= permits) {
- available -= permits;
- attachDetach(permits, address);
- return true;
- }
- return false;
- }
- public boolean onDisconnect(Address deadAddress) {
- Integer attached = attachedPermits.remove(deadAddress);
- if (attached != null && attached != 0) {
- available += attached;
- return true;
- }
- return false;
- }
- @Override
- public String toString() {
- return String.format("Semahpore{available=%d, global attached=%d}", available, getAttached());
- }
- }