| 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.data.spi;

import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import org.gvsig.fmap.data.DataParameters;

import org.gvsig.fmap.data.DataStore;

import org.gvsig.fmap.data.Resource;

import org.gvsig.fmap.data.ResourceNotification;

import org.gvsig.fmap.data.exceptions.CloseException;

import org.gvsig.fmap.data.exceptions.DataException;

import org.gvsig.fmap.data.exceptions.OpenException;

import org.gvsig.fmap.data.exceptions.PrepareResourceException;

import org.gvsig.fmap.data.exceptions.ResourceChangedException;

import org.gvsig.fmap.data.exceptions.ResourceConsumerNotFoundException;

import org.gvsig.fmap.data.exceptions.UnreferenceResourceException;

import org.gvsig.fmap.data.impl.DefaultResourceNotification;

import org.gvsig.tools.observer.DefaultObservable;

import org.gvsig.tools.observer.Observable;

import org.gvsig.tools.observer.Observer;

/**

 * @author jmvivo

 *

 */

public abstract class AbstractResource implements Observable, Resource {

        private List references = new ArrayList();

        private DefaultObservable observable = new DefaultObservable();

        protected Date lastTimeOpen = new Date();

        protected Date lastTimeUsed = new Date();

        protected DataParameters params = null;

        protected AbstractResource(DataParameters params) {

                this.params = params;

        }

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#getParameters()

         */

        public DataParameters getParameters() throws DataException {

                return this.params.getCopy();

        }

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#description()

         */

        public abstract String getDescription();

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#getName()

         */

        public abstract String getName();

        protected abstract String generateKey();

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#getKey()

         */

        public final String getKey(){

                if (this.key == null){

                        this.key = this.generateKey();

                }

                return this.key;

        }

        protected abstract void doChanged();

        private String key=null;

        private boolean opened;

        public final void changed(DataStore store) {

                doChanged();

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.CHANGED,store));

        }

        public final void changed() {

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.CHANGED));

        }

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#close()

         */

        public synchronized final void close() throws CloseException{

                if (!this.isOpen()) {

                        return;

                }

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.BEGIN_CLOSE));

                doClose();

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.CLOSED));

        }

        public final void dispose() throws DataException {

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.BEGIN_DISPOSE));

                doDispose();

                observable.deleteObservers();

                this.references.clear();

        }

        protected abstract void doDispose() throws DataException;

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#getLastTimeOpen()

         */

        public Date getLastTimeOpen() {

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

        }

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#getLastTimeUsed()

         */

        public Date getLastTimeUsed() {

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

        }

        public void incref(Object consumer) {

                this.updateLastTimeUsed();

                if (consumer != null) {

                        this.references.add(new WeakReference(consumer));

                } else {

                        this.references.add(null);

                }

                //                this.referenceCount++;

        }

        protected synchronized final void open() throws OpenException,

                        ResourceChangedException {

                this.updateLastTimeUsed();

                if (this.isOpen()){

                        return;

                }

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.BEGIN_OPEN));

                if (doOpen()) {

                        this.updateLastTimeOpen();

                }

                observable.notifyObservers(

                                this,

                                new DefaultResourceNotification(this,ResourceNotification.OPENED));

        }

        protected void updateLastTimeUsed() {

                if (this.lastTimeUsed == null) {

                        this.lastTimeUsed = new Date();

                }

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

        }

        protected void updateLastTimeOpen(){

                if (this.lastTimeOpen == null){

                        this.lastTimeOpen = new Date();

                }

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

        }

        protected abstract boolean doOpen() throws OpenException,

                        ResourceChangedException;

        /**

         *

         * @param consumer

         * @return ref count after operation

         */

        public void unref(Object consumer) throws DataException {

                if (this.references.size() < 1) {

                        throw new UnreferenceResourceException(this.getKey());

                }

                this.updateLastTimeUsed();

                this.updateReferences();

                int index = -1;

                int i;

                WeakReference ref;

                for (i=0;i<this.references.size();i++){

                        ref = (WeakReference) this.references.get(i);

                        if (ref != null) {

                                if (ref.get().equals(consumer)) {

                                        index = i;

                                        break;

                                }

                        } else if (consumer == null) {

                                index = i;

                                break;

                        }

                }

                if (index < 0) {

                        throw new ResourceConsumerNotFoundException(this, consumer);

                }

                this.references.remove(index);

                if (this.references.size() == 0) {

                        this.close();

                }

        }

        public final int getRefencesCount(){

                this.updateReferences();

                return this.references.size();

        }

        /* (non-Javadoc)

         * @see org.gvsig.util.observer.Observable#addObserver(org.gvsig.tools.observer.Observer)

         */

        public void addObserver(Observer o) {

                this.observable.addObserver(o);

        }

        /* (non-Javadoc)

         * @see org.gvsig.util.observer.Observable#deleteObserver(org.gvsig.tools.observer.Observer)

         */

        public void deleteObserver(Observer o) {

                this.observable.deleteObserver(o);

        }

        /* (non-Javadoc)

         * @see org.gvsig.util.observer.Observable#deleteObservers()

         */

        public void deleteObservers() {

                this.deleteObservers();

        }

        public void addObservers(DefaultObservable ob){

                this.observable.addObservers(ob);

        }

        /**

         *

         */

        public void prepare() throws DataException {

                try{

                        observable.notifyObservers(

                                        this,

                                        new DefaultResourceNotification(this,ResourceNotification.PREPARE));

                } catch (Exception e){

                        throw new PrepareResourceException(this, e);

                }

                this.updateLastTimeUsed();

        }

        protected synchronized void checkOpen() throws OpenException,

                        ResourceChangedException {

                this.updateLastTimeUsed();

                if (!this.isOpen()){

                        this.open();

                } else {

                        this.checkChanged();

                }

        }

        protected abstract void checkChanged() throws ResourceChangedException;

        /* (non-Javadoc)

         * @see org.gvsig.fmap.data.Resource#isOpen()

         */

        public boolean isOpen() {

                return this.opened;

        }

        protected void setOpened() {

                this.updateLastTimeUsed();

                this.opened=true;

        }

        protected boolean doClose() throws CloseException {

                if (!this.isOpen()) {

                        return false;

                }

                this.opened= false;

                return true;

        }

        public synchronized void updateReferences() {

                List deadRefs = new ArrayList();

                WeakReference ref;

                int i;

                for (i = 0; i < this.references.size(); i++) {

                        ref = (WeakReference) this.references.get(i);

                        if (ref == null) {

                                continue;

                        }

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

                                deadRefs.add(new Integer(i));

                        }

                }

                for (i = deadRefs.size(); i > 0; i--) {

                        this.references.remove(((Integer) deadRefs.get(i - 1)).intValue());

                }

        }

}