| gvSIG desktop 1

/* gvSIG. Geographic Information System of the Valencian Government

*

* Copyright (C) 2007-2008 Infrastructures and Transports Department

* of the Valencian Government (CIT)

*

* This program is free software; you can redistribute it and/or

* modify it under the terms of the GNU General Public License

* as published by the Free Software Foundation; either version 2

* of the License, or (at your option) any later version.

*

* This program is distributed in the hope that it will be useful,

* 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, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

* MA  02110-1301, USA.

*

*/

/*

* AUTHORS (In addition to CIT):

* 2008 IVER T.I   {{Task}}

*/

/**

 *

 */

package org.gvsig.fmap.dal.resource.spi;

import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.Date;

import java.util.Iterator;

import java.util.List;

import org.gvsig.fmap.dal.exceptions.CopyParametersException;

import org.gvsig.fmap.dal.exceptions.InitializeException;

import org.gvsig.fmap.dal.resource.ResourceNotification;

import org.gvsig.fmap.dal.resource.ResourceParameters;

import org.gvsig.fmap.dal.resource.exception.AccessResourceException;

import org.gvsig.fmap.dal.resource.exception.PrepareResourceException;

import org.gvsig.fmap.dal.resource.exception.ResourceBeginException;

import org.gvsig.fmap.dal.resource.exception.ResourceException;

import org.gvsig.fmap.dal.resource.exception.ResourceNotifyChangesException;

import org.gvsig.fmap.dal.resource.exception.ResourceNotifyCloseException;

import org.gvsig.fmap.dal.resource.exception.ResourceNotifyDisposeException;

import org.gvsig.fmap.dal.resource.exception.ResourceNotifyOpenException;

import org.gvsig.fmap.dal.resource.impl.DefaultResourceNotification;

import org.gvsig.tools.observer.Observer;

import org.gvsig.tools.observer.WeakReferencingObservable;

import org.gvsig.tools.observer.impl.BaseWeakReferencingObservable;

import org.gvsig.tools.observer.impl.DelegateWeakReferencingObservable;

public abstract class AbstractResource implements ResourceProvider, WeakReferencingObservable {

        private DelegateWeakReferencingObservable delegateObservable;

        private List consumers;

        private Date lastTimeOpen;

        private Date lastTimeUsed;

        private boolean inUse;

        private Object data;

        private int openCount;

        private Object semaforo;

        private ResourceParameters parameters;

        private ResourceParameters preparedParameters;

        protected AbstractResource(ResourceParameters parameters)

                        throws InitializeException {

                try {

                        delegateObservable = new DelegateWeakReferencingObservable(this);

                        consumers = new ArrayList();

                        lastTimeOpen = new Date();

                        lastTimeUsed = new Date();

                        inUse = false;

                        openCount = 0;

                        semaforo = new Object();

                        preparedParameters = null;

                        this.parameters = (ResourceParameters) parameters.getCopy();

                } catch (CopyParametersException e) {

                        throw new InitializeException(e);

                }

        }

        final private void updateLastTimeUsed() {

                this.lastTimeUsed.setTime(System.currentTimeMillis());

        }

        final private void updateLastTimeOpen() {

                this.lastTimeOpen.setTime(System.currentTimeMillis());

                this.updateLastTimeUsed();

        }

        final public Date getLastTimeOpen() {

                return new Date(this.lastTimeOpen.getTime());

        }

        final public Date getLastTimeUsed() {

                return new Date(this.lastTimeOpen.getTime());

        }

        public final ResourceParameters getParameters() {

                if (preparedParameters != null) {

                        return preparedParameters;

                }

                return this.parameters;

        }

        public void prepare(ResourceParameters params)

                        throws PrepareResourceException {

                ResourceNotification notification = new DefaultResourceNotification(

                                this, ResourceNotification.PREPARE, params);

                this.delegateObservable.notifyObservers(notification);

        }

        public void prepare() throws PrepareResourceException {

                if (preparedParameters == null) {

                        try {

                                ResourceParameters params = (ResourceParameters) parameters

                                                .getCopy();

                                prepare(params);

                                preparedParameters = params;

                        } catch (CopyParametersException e) {

                                throw new PrepareResourceException(this, e);

                        }

                }

        }

        public final void begin() throws ResourceBeginException {

                synchronized (semaforo) {

                        if (inUse) {

                                try {

                                        semaforo.wait();

                                } catch (InterruptedException e) {

                                        throw new ResourceBeginException(this, e);

                                }

                        }

                        inUse = true;

                        updateLastTimeUsed();

                }

        }

        public final void end() {

                synchronized (semaforo) {

                        if (!inUse) {

                                return;

                        }

                        updateLastTimeUsed();

                        inUse = false;

                        semaforo.notifyAll();

                }

        }

        public final boolean inUse() {

                return inUse;

        }

        public void notifyOpen() throws ResourceNotifyOpenException {

                this.notifyObserver(ResourceNotification.OPEN);

                updateLastTimeOpen();

                openCount++;

        }

        public void notifyClose() throws ResourceNotifyCloseException {

                if (openCount <= 0) {

                        throw new IllegalStateException();

                }

                this.notifyObserver(ResourceNotification.CLOSE);

                openCount--;

        }

        public void notifyChanges() throws ResourceNotifyChangesException {

                this.notifyObserver(ResourceNotification.CHANGED);

        }

        public void notifyDispose() throws ResourceNotifyDisposeException {

                this.notifyObserver(ResourceNotification.DISPOSE);

                consumers.clear();

                consumers = null;

                lastTimeOpen = null;

                lastTimeUsed = null;

                data = null;

                semaforo = null;

                delegateObservable.deleteObservers();

                delegateObservable = null;

        }

        public boolean isOpen() {

                return this.openCount > 0;

        }

        public int openCount() {

                return this.openCount;

        }

        public void addObserver(Observer o) {

                this.delegateObservable.addObserver(o);

        }

        public void deleteObserver(Observer o) {

                this.delegateObservable.deleteObserver(o);

        }

        public void deleteObservers() {

                this.delegateObservable.deleteObservers();

        }

        public final void addObservers(BaseWeakReferencingObservable observers) {

                this.delegateObservable.addObservers(observers);

        }

        public final void addConsumer(ResourceConsumer consumer) {

                this.updateConsumersList();

                consumers.add(new WeakReference(consumer));

        }

        public final void removeConsumer(ResourceConsumer consumer) {

                this.updateConsumersList();

                consumers.remove(consumer);

        }

        public int getConsumersCount() {

                this.updateConsumersList();

                return consumers.size();

        }

        private synchronized void updateConsumersList() {

                Iterator it = consumers.iterator();

                WeakReference ref;

                while (it.hasNext()) {

                        ref = (WeakReference) it.next();

                        if (ref.get() == null) {

                                it.remove();

                        }

                }

        }

        public void closeRequest() throws ResourceException {

                if (inUse) {

                        return;

                }

                Iterator it = consumers.iterator();

                while (it.hasNext()) {

                        ResourceConsumer consumer = (ResourceConsumer) ((WeakReference) it

                                        .next()).get();

                        if (consumer != null) {

                                consumer.closeResourceRequested(this);

                        }

                }

        }

        public void setData(Object data) {

                this.data = data;

        }

        public Object getData() {

                return this.data;

        }

        protected void notifyObserver(String type) {

                this.delegateObservable

                .notifyObservers(new DefaultResourceNotification(

                                this, type));

        }

        public abstract String getName() throws AccessResourceException;

        public abstract Object get() throws AccessResourceException;

}