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This is the master POM file for Oracle's Implementation of the JSF 2.2 Specification.

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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.faces.facelets.impl;


import javax.faces.view.facelets.FaceletCache;
import com.sun.faces.util.ConcurrentCache;
import com.sun.faces.util.ExpiringConcurrentCache;

import javax.faces.FacesException;
import java.io.IOException;
import java.io.InputStream;

import java.net.URL;
import java.net.URLConnection;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.atomic.AtomicLong;


/**
 * Default FaceletCache implementation.
 */
final class DefaultFaceletCache extends FaceletCache {

    /**
     *Constructor
     * @param refreshPeriod cache refresh period (in milliseconds).
     * 0 means 'always refresh', negative value means 'never refresh'
     */
    DefaultFaceletCache(final long refreshPeriod) {

        // We will be delegating object storage to the ExpiringCocurrentCache
        // Create Factory objects here for the cache. The objects will be delegating to our
        // own instance factories
        
        final boolean checkExpiry = (refreshPeriod > 0);

        ConcurrentCache.Factory faceletFactory =
            new ConcurrentCache.Factory() {
            public Record newInstance(final URL key) throws IOException {
                // Make sure that the expensive timestamp retrieval is not done
                // if no expiry check is going to be performed
                long lastModified = checkExpiry ? _getLastModified(key) : 0;
                return new Record(System.currentTimeMillis(), lastModified,
                                  getMemberFactory().newInstance(key), refreshPeriod);
            }
        };

        ConcurrentCache.Factory metadataFaceletFactory =
            new ConcurrentCache.Factory() {
            public Record newInstance(final URL key) throws IOException {
                // Make sure that the expensive timestamp retrieval is not done
                // if no expiry check is going to be performed
                long lastModified = checkExpiry ? _getLastModified(key) : 0;
                return new Record(System.currentTimeMillis(), lastModified,
                                  getMetadataMemberFactory().newInstance(key), refreshPeriod);
            }
        };

        // No caching if refreshPeriod is 0
        if (refreshPeriod == 0) {
            _faceletCache = new NoCache(faceletFactory);
            _metadataFaceletCache = new NoCache(metadataFaceletFactory);
        } else {
            ExpiringConcurrentCache.ExpiryChecker checker = 
                (refreshPeriod > 0) ? new ExpiryChecker() : new NeverExpired();
            _faceletCache =
                    new ExpiringConcurrentCache(faceletFactory,
                                                             checker);
            _metadataFaceletCache =
                    new ExpiringConcurrentCache(metadataFaceletFactory,
                                                             checker);
        }
    }

    @Override
    public DefaultFacelet getFacelet(URL url) throws IOException {
        com.sun.faces.util.Util.notNull("url", url);
        DefaultFacelet f = null;
        
        try {
            f =  _faceletCache.get(url).getFacelet();
        } catch (ExecutionException e) {
            _unwrapIOException(e);
        }
        return f;
    }

    @Override
    public boolean isFaceletCached(URL url) {
        com.sun.faces.util.Util.notNull("url", url);

        return _faceletCache.containsKey(url);
    }


    @Override
    public DefaultFacelet getViewMetadataFacelet(URL url) throws IOException {
        com.sun.faces.util.Util.notNull("url", url);

        DefaultFacelet f = null;
        
        try {
            f = _metadataFaceletCache.get(url).getFacelet();
        } catch (ExecutionException e) {
            _unwrapIOException(e);
        }
        return f;
    }

    @Override
    public boolean isViewMetadataFaceletCached(URL url) {
        com.sun.faces.util.Util.notNull("url", url);

        return _metadataFaceletCache.containsKey(url);
    }

    private void _unwrapIOException(ExecutionException e) throws IOException {
        Throwable t = e.getCause();
        if (t instanceof IOException) {
            throw (IOException)t;
        }
        if (t instanceof RuntimeException) {
            throw (RuntimeException)t;
        }
        throw new FacesException(t);
    }
    
    private static long _getLastModified(URL url) {
        InputStream is = null;
        try {
            URLConnection conn = url.openConnection();
            is = conn.getInputStream();
            return conn.getLastModified();
        } catch (Exception e) {
            throw new FacesException("Error Checking Last Modified for " +
                                       url, e);
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (Exception e) {
                    // do nothing
                }
            }
        }
    }

    private final ConcurrentCache _faceletCache;
    private final ConcurrentCache _metadataFaceletCache;

    /**
     * This class holds the Facelet instance and its original URL's last modified time. It also produces
     * the time when the next expiry check should be performed
     */
    private static class Record {
        Record(long creationTime, long lastModified, DefaultFacelet facelet, long refreshInterval) {
            _facelet = facelet;
            _creationTime = creationTime;
            _lastModified = lastModified;
            _refreshInterval = refreshInterval;
            
            // There is no point in calculaing the next refresh time if we are refreshing always/never
            _nextRefreshTime = (_refreshInterval > 0) ? new AtomicLong(creationTime + refreshInterval) : null;
        }

        DefaultFacelet getFacelet() {
            return _facelet;
        }

        long getLastModified() {
            return _lastModified;
        }
        
        long getNextRefreshTime() {
            // There is no point in calculaing the next refresh time if we are refreshing always/never
            return (_refreshInterval > 0) ? _nextRefreshTime.getAndAdd(_refreshInterval) : 0;
        }
        
        private final long _lastModified;
        private final long _refreshInterval;
        private final long _creationTime;
        private final AtomicLong _nextRefreshTime;
        private final DefaultFacelet _facelet;
    }

    private static class ExpiryChecker implements ExpiringConcurrentCache.ExpiryChecker {

        public boolean isExpired(URL url, Record record) {
            // getNextRefreshTime() incremenets the next refresh time atomically
            long ttl = record.getNextRefreshTime();
            if (System.currentTimeMillis() > ttl) {
                long lastModified = _getLastModified(url);
                // The record is considered expired if its original last modified time
                // is older than the URL's current last modified time
                return (lastModified > record.getLastModified());
            }
            return false;
        }
    }
    
    private static class NeverExpired implements ExpiringConcurrentCache.ExpiryChecker {
        public boolean isExpired(URL key, Record value) {
            return false;
        }
    }

    /**
     * ConcurrentCache implementation that does no caching (always creates new instances)
     */
    private static class NoCache extends ConcurrentCache {
        public NoCache(ConcurrentCache.Factory f) {
            super(f);
        }

        public Record get(final URL key) throws ExecutionException {
            try {
                return this.getFactory().newInstance(key);
            } catch (Exception e) {
                throw new ExecutionException(e);
            }
        }

        public boolean containsKey(final URL key) {
            return false;
        }
    }
}




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