Semaphore.java

/*
 * GovWay - A customizable API Gateway 
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 * 
 * Copyright (c) 2005-2025 Link.it srl (https://link.it). 
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3, as published by
 * the Free Software Foundation.
 *
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package org.openspcoop2.utils;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;

import org.slf4j.Logger;

/**
 * Semaphore
 *
 *
 * @author Poli Andrea (apoli@link.it)
 * @author $Author$
 * @version $Rev$, $Date$
 */
public class Semaphore {

    public static final long DEFAULT_LOCK_ACQUISITION_TIMEOUT_MS = 30000;
    private static long defaultLockAcquisitionTimeoutMs = DEFAULT_LOCK_ACQUISITION_TIMEOUT_MS;
    public static long getDefaultLockAcquisitionTimeoutMs() {
        return defaultLockAcquisitionTimeoutMs;
    }
    public static void setDefaultLockAcquisitionTimeoutMs(long timeoutMs) {
        defaultLockAcquisitionTimeoutMs = timeoutMs;
    }
    
    public static final long DEFAULT_LOCK_HOLD_TIMEOUT_MS = 60000;
    private static long defaultLockHoldTimeoutMs = DEFAULT_LOCK_HOLD_TIMEOUT_MS;
    public static long getDefaultLockHoldTimeoutMs() {
        return defaultLockHoldTimeoutMs;
    }
    public static void setDefaultLockHoldTimeoutMs(long timeoutMs) {
        defaultLockHoldTimeoutMs = timeoutMs;
    }
    
    private static Logger logDebug = null;
    public static Logger getLogDebug() {
        return logDebug;
    }
    public static void setLogDebug(Logger logDebug) {
        Semaphore.logDebug = logDebug;
    }

    private static boolean defaultDebug = false;
    public static boolean isDefaultDebug() {
        return defaultDebug;
    }
    public static void setDefaultDebug(boolean d) {
        defaultDebug = d;
    }
    
    private Long instanceLockAcquisitionTimeoutMs = null;
    public long getInstanceLockAcquisitionTimeoutMs() {
        return this.instanceLockAcquisitionTimeoutMs != null && this.instanceLockAcquisitionTimeoutMs.longValue()>0 ? this.instanceLockAcquisitionTimeoutMs : defaultLockAcquisitionTimeoutMs;
    }
    public void setInstanceLockAcquisitionTimeoutMs(Long timeoutMs) {
        this.instanceLockAcquisitionTimeoutMs = timeoutMs;
    }
    public void setInstanceLockAcquisitionTimeoutMs(long timeoutMs) {
        this.instanceLockAcquisitionTimeoutMs = timeoutMs;
    }
    
    private long instanceLockHoldTimeoutMs = -1;
    public long getInstanceLockHoldTimeoutMs() {
        return this.instanceLockHoldTimeoutMs>0 ? this.instanceLockHoldTimeoutMs : defaultLockHoldTimeoutMs;
    }
    public void setInstanceLockHoldTimeoutMs(long timeoutMs) {
        this.instanceLockHoldTimeoutMs = timeoutMs;
    }

    private boolean instanceDebug = false;
    public boolean isInstanceDebug() {
        return this.instanceDebug || defaultDebug;
    }
    public void setInstanceDebug(boolean d) {
        this.instanceDebug = d;
    }

    private static SemaphoreType semaphoreType = SemaphoreType.Semaphore;
    public static SemaphoreType getSemaphoreType() {
        return semaphoreType;
    }
    public static void setSemaphoreType(SemaphoreType semaphoreType) {
        Semaphore.semaphoreType = semaphoreType;
    }

    private static boolean fair = true;
    public static boolean isFair() {
        return fair;
    }
    public static void setFair(boolean fair) {
        Semaphore.fair = fair;
    }

    private final java.util.concurrent.Semaphore concurrentSemaphore;
    private final java.util.concurrent.locks.ReentrantLock reentrantLock;
    private String semaphoreName = null;
    private int permits = -1;
    
    public Semaphore(String name) {
        this(name, Semaphore.semaphoreType, Semaphore.fair);
    }
    public Semaphore(String name, boolean fair) {
        this(name, Semaphore.semaphoreType, fair);
    }
    public Semaphore(String name, SemaphoreType semaphoreType, boolean fair) {
        this.semaphoreName = name;
        switch (semaphoreType) {
        case ReentrantLock:
            this.reentrantLock = new ReentrantLock(fair); 
            this.concurrentSemaphore = null;
            break;
        case Semaphore:
            this.reentrantLock = null; 
            this.concurrentSemaphore = new java.util.concurrent.Semaphore(1, fair);
            break;
        default:
            this.reentrantLock = null;
            this.concurrentSemaphore = null;
        }
        this.permits = 1;
    }
    
    public Semaphore(String name, int permits) {
        this(name, permits, Semaphore.fair);
    }
    public Semaphore(String name, int permits, boolean fair) {
        this.semaphoreName = name;
        this.concurrentSemaphore = new java.util.concurrent.Semaphore(permits, fair);
        this.reentrantLock = null;
        this.permits = permits;
    }
    
    public boolean hasQueuedThreads() {
        if(this.concurrentSemaphore!=null) {
            return this.concurrentSemaphore.hasQueuedThreads();
        }
        else {
            return this.reentrantLock.hasQueuedThreads();
        }
    }
    public boolean available() {
        if(this.concurrentSemaphore!=null) {
            return this.concurrentSemaphore.availablePermits()>0;
        }
        else {
            return !this.reentrantLock.isLocked();
        }
    }
    public int availablePermits() {
        if(this.concurrentSemaphore!=null) {
            return this.concurrentSemaphore.availablePermits();
        }
        else {
            return -1;
        }
    }
    
    String getPrefix(String methodName, String idTransazione) {
        String idTr = "";
        if(idTransazione!=null) {
            idTr = " (idTransazione:"+idTransazione+")";
        }
        return this.semaphoreName+"."+methodName+" [Thread:"+Thread.currentThread().getName()+"]"+idTr+" ";
    }
    
    public SemaphoreLock acquire(String methodName) throws UtilsException {
        return this.acquire(methodName, null);
    }
    public SemaphoreLock acquire(String methodName, String idTransazione) throws UtilsException {
        try {
            if(this.getInstanceLockAcquisitionTimeoutMs()<=0) {
                return acquireWithoutTimeout(methodName, idTransazione);
            }
            else {
                return acquireWithTimeout(methodName, idTransazione);
            }
        }
        catch(InterruptedException ie) {
            if(this.isInstanceDebug()) {
                debug(getPrefix(methodName, idTransazione)+" acquire("+this.getInstanceLockAcquisitionTimeoutMs()+"ms) failed: "+ie.getMessage());
            }
            Thread.currentThread().interrupt();
            throw new UtilsException(ie.getMessage(),ie);
        }
    }
    private SemaphoreLock acquireWithoutTimeout(String methodName, String idTransazione) throws InterruptedException {
        if(this.isInstanceDebug()) {
            debug(getPrefix(methodName, idTransazione)+" acquire ...");
        }
        if(this.concurrentSemaphore!=null) {
            this.concurrentSemaphore.acquire();
        }
        else {
            this.reentrantLock.lock();
        }
        if(this.isInstanceDebug()) {
            debug(getPrefix(methodName, idTransazione)+" acquired");
        }
        return new SemaphoreLock(this, methodName, idTransazione);
    }
    private SemaphoreLock acquireWithTimeout(String methodName, String idTransazione) throws InterruptedException {
        if(this.isInstanceDebug()) {
            debug(getPrefix(methodName, idTransazione)+" acquire("+this.getInstanceLockAcquisitionTimeoutMs()+"ms) ...");
        }
        boolean acquire = false;
        if(this.concurrentSemaphore!=null) {
            acquire = this.concurrentSemaphore.tryAcquire(this.getInstanceLockAcquisitionTimeoutMs(), TimeUnit.MILLISECONDS);
        }
        else {
            acquire = this.reentrantLock.tryLock(this.getInstanceLockAcquisitionTimeoutMs(), TimeUnit.MILLISECONDS);
        }
        if(!acquire) {
            throw new InterruptedException("["+this.semaphoreName+"] Could not acquire semaphore after "+this.getInstanceLockAcquisitionTimeoutMs()+"ms");
        }
        if(this.isInstanceDebug()) {
            debug(getPrefix(methodName, idTransazione)+" acquired");
        }
        return new SemaphoreLock(this, methodName, idTransazione);
    }
    
    public SemaphoreLock acquireThrowRuntime(String methodName) throws SemaphoreRuntimeException {
        return this.acquireThrowRuntime(methodName, null);
    }
    public SemaphoreLock acquireThrowRuntime(String methodName, String idTransazione) throws SemaphoreRuntimeException {
        try {
            return this.acquire(methodName, idTransazione);
        }
        catch(Exception t) {
            throw new SemaphoreRuntimeException(t.getMessage(),t);
        }
    }
    
    public void release(SemaphoreLock semaphoreLock, String methodName) {
        this.release(semaphoreLock, methodName, null);
    }
    public void release(SemaphoreLock semaphoreLock, String methodName, String idTransazione) {
        if(this.isInstanceDebug()) {
            debug(getPrefix(methodName, idTransazione)+" release ...");
        }
        if(this.concurrentSemaphore!=null) {
            if(this.concurrentSemaphore.availablePermits()<this.permits) {
                this.concurrentSemaphore.release(); // altrimenti ogni release utilizzato male fa incrementare i permessi
            }
        }
        else {
            this.reentrantLock.unlock();
        }
        if(semaphoreLock!=null) {
            semaphoreLock.release(methodName, idTransazione);
        }
        if(this.isInstanceDebug()) {
            debug(getPrefix(methodName, idTransazione)+" released");
        }
    }
    
    void debug(String msg) {
        System.out.println(msg);
    }
}

@SuppressWarnings("serial")
class SemaphoreRuntimeException extends RuntimeException{

    public SemaphoreRuntimeException() {
        super();
    }

    public SemaphoreRuntimeException(String message, Throwable cause, boolean enableSuppression,
            boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }

    public SemaphoreRuntimeException(String message, Throwable cause) {
        super(message, cause);
    }

    public SemaphoreRuntimeException(String message) {
        super(message);
    }

    public SemaphoreRuntimeException(Throwable cause) {
        super(cause);
    }
    
}