/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cocoon.generation;
import org.apache.avalon.framework.component.Recomposable;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.ComponentException;
import org.apache.cocoon.caching.CacheValidity;
import org.apache.cocoon.caching.Cacheable;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.components.language.generator.CompiledComponent;
import org.apache.cocoon.environment.Request;
import org.apache.excalibur.source.SourceValidity;
import org.apache.excalibur.source.impl.validity.NOPValidity;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import java.io.File;
import java.io.Serializable;
/**
* Base implementation of <code>ServerPagesGenerator</code>. This class
* declares variables that must be explicitly initialized by code generators.
*
* @author <a href="mailto:ricardo@apache.org">Ricardo Rocha</a>
* @version CVS $Id$
*/
public abstract class AbstractServerPage
extends ServletGenerator
implements CompiledComponent, CacheableProcessingComponent, Cacheable, Recomposable {
/**
* Code generators should produce a constructor
* block that initializes the generator's
* creation date and file dependency list.
* Example:
*
* {
* this.dateCreated = 958058788948L;
* this.dependencies = new File[] {
* new File("source.xml"),
* };
* }
*
*/
/** The creation date */
protected long dateCreated = -1L;
/** The dependency file list */
protected File[] dependencies = null;
/**
* Recompose with the actual <code>ComponentManager</code> that should
* be used.
*/
public void recompose(ComponentManager manager) throws ComponentException {
this.manager = manager;
}
/**
* Determines whether this generator's source files have changed
*
* @return Whether any of the files this generator depends on has changed
* since it was created
*/
public boolean modifiedSince(long date) {
if (date == 0 || dateCreated < date) {
return true;
}
for (int i = 0; i < dependencies.length; i++) {
if (dateCreated < dependencies[i].lastModified()) {
return true;
}
}
return false;
}
/**
* Determines whether generated content has changed since
* last invocation. Users may override this method to take
* advantage of SAX event cacheing
*
* @param request The request whose data must be inspected to assert whether
* dynamically generated content has changed
* @return Whether content has changes for this request's data
*/
public boolean hasContentChanged(Request request) {
return true;
}
/**
* Generate the unique key.
* This key must be unique inside the space of this component.
* This method must be invoked before the generateValidity() method.
*
* @return The generated key or <code>null</code> if the component
* is currently not cacheable.
*/
public Serializable getKey() {
return null;
}
/**
* Generate the validity object.
* Before this method can be invoked the generateKey() method
* must be invoked.
*
* @return The generated validity object, <code>NOPCacheValidity</code>
* is the default if hasContentChange() gives false otherwise
* <code>null</code> will be returned.
*/
public SourceValidity getValidity() {
if (hasContentChanged(request))
return null;
else
return NOPValidity.SHARED_INSTANCE;
}
// FIXME: Add more methods!
/* SAX Utility Methods */
/**
* Add an attribute
*
* @param attr The attribute list to add to
* @param name The attribute name
* @param value The attribute value
*/
protected void attribute(AttributesImpl attr, String name, String value) {
attr.addAttribute("", name, name, "CDATA", value);
}
/**
* Start an element
*
* @param name The element name
* @param attr The element attributes
*/
protected void start(String name, AttributesImpl attr) throws SAXException {
this.contentHandler.startElement("", name, name, attr);
attr.clear();
}
/**
* End an element
*
* @param name The element name
*/
protected void end(String name) throws SAXException {
this.contentHandler.endElement("", name, name);
}
/**
* Add character data
*
* @param data The character data
*/
protected void characters(String data) throws SAXException {
this.contentHandler.characters(data.toCharArray(), 0, data.length());
}
/**
* Add a comment
*
* @param data The comment data
*/
protected void comment(String data) throws SAXException {
this.lexicalHandler.comment(data.toCharArray(), 0, data.length());
}
/**
* Generates the unique key.
* This key must be unique inside the space of this component.
* Users may override this method to take
* advantage of SAX event cacheing
*
* @return A long representing the cache key (defaults to not cachable)
*/
public long generateKey() {
return 0;
}
/**
* Generate the validity object.
*
* @return The generated validity object, <code>NOPCacheValidity</code>
* is the default if hasContentChange() gives false otherwise
* <code>null</code> will be returned.
*/
public CacheValidity generateValidity() {
if (hasContentChanged(request))
return null;
else
return NOPCacheValidity.CACHE_VALIDITY;
}
}
/**
* This is here to avaid references to the deprecated package.
* It is required to support the deprecated caching algorithm
*/
final class NOPCacheValidity
implements CacheValidity {
public static final CacheValidity CACHE_VALIDITY = new NOPCacheValidity();
public boolean isValid(CacheValidity validity) {
return validity instanceof NOPCacheValidity;
}
public String toString() {
return "NOP Validity";
}
}