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From: maciejka@tiger.com.pl
To: cocoon-dev@xml.apache.org
Date: Wed, 4 Jul 2001 17:43:46 +0200
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Subject: CachingCIncludeTransformer
Reply-to: maciejka@tiger.com.pl
Message-ID: <3B4355D2.8417.55083F3@localhost>
Priority: normal

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I am attaching code of CachingCIncludeTransformer, IncludeCacheValidity and xml
files to try it.

Is just a try to attack problem of caching cinclude transformer. Current 
caching framework design hardly makes it possible. One has to use CacheValidity
objects in a hacky way.

As ContentAggregator it caches only if includes are files, since sitemap 
sources always return getLastModified() == 0.

Anyone works on caching sitemap includes in ContentAggregator?

P.S.:
To try it one should change 

<map:transformer 
    name="cinclude"
    src="org.apache.cocoon.transformation.CIncludeTransformer"/>

to

<map:transformer 
    name="cinclude"
    src="org.apache.cocoon.transformation.CachingCIncludeTransformer"/>

and add something like:

   <map:match pattern="x.xml">
     <map:generate src="x.xml"/>
     <map:transform type="cinclude"/>
     <map:serialize type="xml"/>       
   </map:match>

to sitemap.xmap and put x.xml, y.xml, z.xml into webapp dir.


Maciek Kaminski
maciejka@tiger.com.pl


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/*****************************************************************************
 * Copyright (C) The Apache Software Foundation. All rights reserved.        *
 * ------------------------------------------------------------------------- *
 * This software is published under the terms of the Apache Software License *
 * version 1.1, a copy of which has been included  with this distribution in *
 * the LICENSE file.                                                         *
 *****************************************************************************/
package org.apache.cocoon.transformation;

import java.io.IOException;
import java.util.Map;
import org.apache.avalon.excalibur.pool.Recyclable;
import org.apache.avalon.framework.component.ComponentException;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.Composable;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.Roles;
import org.apache.cocoon.caching.EventCache;
import org.apache.cocoon.caching.Cacheable;
import org.apache.cocoon.caching.CacheValidity;
import org.apache.cocoon.caching.IncludeCacheValidity;
import org.apache.cocoon.caching.TimeStampCacheValidity;
import org.apache.cocoon.components.parser.Parser;
import org.apache.cocoon.environment.Source;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.xml.IncludeXMLConsumer;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import org.apache.cocoon.util.HashUtil;

/**
 * This transformer triggers for the element <code>include</code> in the
 * namespace "http://apache.org/cocoon/include/1.0".
 * The <code>src></code> attribute contains the url which points to
 * an xml resource which is include instead of the element.
 * With the attributes <code>element</code>, <code>ns</code> and
 * <code>prefix</code> it is possible to specify an element
 * which surrounds the included content.
 *
 * @author <a href="mailto:cziegeler@apache.org">Carsten Ziegeler</a>
 * @version CVS $Revision: 1.2 $ $Date: 2001/06/19 13:39:21 $ $Author: cziegeler $
 */
public class CachingCIncludeTransformer extends AbstractTransformer
implements Recyclable, Composable, Cacheable {

    public static final String CINCLUDE_NAMESPACE_URI = "http://apache.org/cocoon/include/1.0";
    public static final String CINCLUDE_INCLUDE_ELEMENT = "include";
    public static final String CINCLUDE_INCLUDE_ELEMENT_SRC_ATTRIBUTE = "src";
    public static final String CINCLUDE_INCLUDE_ELEMENT_ELEMENT_ATTRIBUTE = "element";
    public static final String CINCLUDE_INCLUDE_ELEMENT_NS_ATTRIBUTE = "ns";
    public static final String CINCLUDE_INCLUDE_ELEMENT_PREFIX_ATTRIBUTE = "prefix";

    /** The <code>SourceResolver</code> */
    protected SourceResolver sourceResolver;

    /** The current <code>ComponentManager</code>. */
    protected ComponentManager manager = null;

    protected EventCache eventCache;

    protected IncludeCacheValidity currentCacheValidity;

    /**
     * Setup the component.
     */
    public void setup(SourceResolver resolver, Map objectModel,
                      String source, Parameters parameters)
    throws ProcessingException, SAXException, IOException {
        this.sourceResolver = resolver;
    }

    /**
     * Composable Interface
     */
    public final void compose(final ComponentManager manager) throws ComponentException {
        this.manager = manager;
        this.eventCache = (EventCache)this.manager.lookup(Roles.EVENT_CACHE);
    }

    /**
     * Recycle the component
     */
    public void recycle() {
        super.recycle();
        this.sourceResolver = null;
    }

    public void startElement(String uri, String name, String raw, Attributes attr)
    throws SAXException {
        if (uri != null && name != null
            && uri.equals(CINCLUDE_NAMESPACE_URI)
            && name.equals(CINCLUDE_INCLUDE_ELEMENT)) {

            this.processCIncludeElement(attr.getValue("",CINCLUDE_INCLUDE_ELEMENT_SRC_ATTRIBUTE),
                                        attr.getValue("",CINCLUDE_INCLUDE_ELEMENT_ELEMENT_ATTRIBUTE),
                                        attr.getValue("",CINCLUDE_INCLUDE_ELEMENT_NS_ATTRIBUTE),
                                        attr.getValue("",CINCLUDE_INCLUDE_ELEMENT_PREFIX_ATTRIBUTE));

        } else {
            super.startElement(uri, name, raw, attr);
        }
    }

    public void endElement(String uri, String name, String raw) throws SAXException {
        if (uri != null && name != null
            && uri.equals(CINCLUDE_NAMESPACE_URI)
            && name.equals(CINCLUDE_INCLUDE_ELEMENT)) {
            return;
        }
        super.endElement(uri, name, raw);
    }

    public void endDocument()
    throws SAXException {
        super.endDocument();
        currentCacheValidity.setIsNew2False();
    }

    protected void processCIncludeElement(String src, String element, String ns, String prefix)
    throws SAXException {

        try {
            currentCacheValidity.add(src, sourceResolver.resolve(src).getLastModified());
        } catch (Exception e) {
            getLogger().error("CachingCIncludeTransformer could not resolve resource", e);
            throw new SAXException("CachingCIncludeTransformer could not resolve resource", e);
        }

        if (element == null) element="";
        if (ns == null) ns="";
        if (prefix == null) prefix="";

        getLogger().debug("Processing CInclude element: src=" + src
                          + ", element=" + element
                          + ", ns=" + ns
                          + ", prefix=" + prefix);

        if (!"".equals(element)) {
            AttributesImpl attrs = new AttributesImpl();
            if (!ns.equals("")) {
                super.startPrefixMapping(prefix, ns);
            }
            super.startElement(ns,
                               element,
                               (!ns.equals("") && !prefix.equals("") ? prefix+":"+element : element),
                               attrs);
        }

/* Look's more simple and should be faster, but does not work
        try {
            this.sourceResolver.resolve(src).stream(this);
        } catch (Exception e) {
            getLogger().error("CIncludeTransformer", e);
            throw new SAXException("CIncludeTransformer could not read resource", e);
        }
*/

        Parser parser = null;
        try {

            IncludeXMLConsumer consumer = new IncludeXMLConsumer(this);

            parser = (Parser)this.manager.lookup(Roles.PARSER);

            parser.setConsumer(consumer);
            parser.parse(this.sourceResolver.resolve(src).getInputSource());
        } catch (IOException e) {
            getLogger().error("CIncludeTransformer", e);
            throw new SAXException("CIncludeTransformer could not read resource", e);
        } catch (SAXException e) {
            getLogger().error("CIncludeTransformer", e);
            throw(e);
        } catch (Exception e){
            getLogger().error("Could not get parser", e);
            throw new SAXException("Exception in CIncludeTransformer",e);
        } finally {
            if (parser != null) this.manager.release(parser);
        }

        if (!"".equals(element)) {
            super.endElement(ns, element, (!ns.equals("") && !prefix.equals("") ? prefix+":"+element : element));
            if (!ns.equals("")) {
                super.endPrefixMapping(prefix);
            }
        }
    }

    /**
     * Generate the unique key.
     * This key must be unique inside the space of this component.
     *
     * @return The generated key hashes the src
     */

    public long generateKey() {
            return 1;
    }

    /**
     * Generate the validity object.
     *
     * @return The generated validity object or <code>null</code> if the
     *         component is currently not cacheable.
     */

    public CacheValidity generateValidity() {

        try {
            currentCacheValidity = new IncludeCacheValidity(sourceResolver);
            return currentCacheValidity;
        } catch (Exception e) {
            getLogger().error("CachingCIncludeTransformer: could not generateKey", e);
            return null;
        }
    }
}

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package org.apache.cocoon.caching;

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;

import org.apache.cocoon.environment.SourceResolver;

public final class IncludeCacheValidity implements CacheValidity {

    private List sources;
    private List timeStamps;

    private boolean isNew;

    private SourceResolver resolver;

    public IncludeCacheValidity(SourceResolver resolver) {
        this.resolver = resolver;
        sources = new ArrayList();
        timeStamps = new ArrayList();
        isNew = true;
    }

    public boolean isNew() {
        return isNew;
    }

    public void setIsNew2False() {
        isNew = false;
        resolver = null;
    }

    public void add(String source, long timeStamp) {
        this.sources.add(source);
        this.timeStamps.add(new Long(timeStamp));
    }

    public boolean isValid(CacheValidity validity) {
        if (validity instanceof IncludeCacheValidity) {
            SourceResolver otherResolver = ((IncludeCacheValidity) validity).resolver;

            for(Iterator i = sources.iterator(), j = timeStamps.iterator(); i.hasNext();) {
                String src = ((String)i.next());
                long timeStamp = ((Long)j.next()).longValue();
                try {
                    if( otherResolver.resolve(src).getLastModified()!= timeStamp )
                        return false;
                } catch (Exception e) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }

    public String toString() {
        StringBuffer b = new StringBuffer("IncludeCacheValidity: " );
        for(Iterator i = sources.iterator(), j = timeStamps.iterator(); i.hasNext();) {
            b.append("[");
            b.append(i.next());
            b.append(" - ");
            b.append(j.next());
            b.append("]");
            if(i.hasNext()) b.append(", ");
        }
        return b.toString();
    }
}

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<?xml version="1.0" encoding="UTF-8"?>
<x xmlns:cinclude="http://apache.org/cocoon/include/1.0">
    <cinclude:include src="y.xml"/>
    <cinclude:include src="z.xml"/>
</x>

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<?xml version="1.0" encoding="UTF-8"?>
<y/>

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<?xml version="1.0" encoding="UTF-8"?>
<z/>


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