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/*******************************************************************************
*
* Copyright (c) 2004-2010 Oracle Corporation.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
*
* Kohsuke Kawaguchi
*
*******************************************************************************/
package org.kohsuke.stapler.framework.adjunct;
import org.apache.commons.jelly.XMLOutput;
import org.kohsuke.stapler.Stapler;
import org.kohsuke.stapler.StaplerRequest;
import org.xml.sax.SAXException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* This request-scope object keeps track of which {@link Adjunct}s are already included.
*
* @author Kohsuke Kawaguchi
*/
public class AdjunctsInPage {
private final AdjunctManager manager;
/**
* All adjuncts that are already included in the page.
*/
private final Set included = new HashSet();
/**
* {@link Adjunct}s that haven't written to HTML yet because <head>
* tag hasn't been written yet.
*/
private final List pending = new ArrayList();
private final StaplerRequest request;
/**
* Obtains the instance associated with the current request of the given {@link StaplerRequest}.
*/
public static AdjunctsInPage get() {
return get(Stapler.getCurrentRequest());
}
/**
* Obtains the instance associated with the current request of the given {@link StaplerRequest}.
*
*
* This method is handy when the caller already have the request object around,
* so that we can save {@link Stapler#getCurrentRequest()} call.
*/
public static AdjunctsInPage get(StaplerRequest request) {
AdjunctsInPage aip = (AdjunctsInPage) request.getAttribute(KEY);
if(aip==null)
request.setAttribute(KEY,aip=new AdjunctsInPage(AdjunctManager.get(request.getServletContext()),request));
return aip;
}
private AdjunctsInPage(AdjunctManager manager,StaplerRequest request) {
this.manager = manager;
this.request = request;
}
/**
* Generates the script tag and CSS link tag to include necessary adjuncts,
* and records the fact that those adjuncts are already included in the page,
* so that it won't be loaded again.
*/
public void generate(XMLOutput out, String... includes) throws IOException, SAXException {
List needed = new ArrayList();
for (String include : includes)
findNeeded(include,needed);
for (Adjunct adj : needed)
adj.write(request,out);
}
/**
* When you include your version of the adjunct externally, you can use
* this method to inform {@link AdjunctsInPage} that those adjuncts are
* already included in the page.
*/
public void assumeIncluded(String... includes) throws IOException, SAXException {
List needed = new ArrayList();
for (String include : includes)
findNeeded(include,needed);
}
/**
* Works like the {@link #generate(XMLOutput, String...)} method
* but just put the adjuncts to {@link #pending} without writing it.
*/
public void spool(String... includes) throws IOException, SAXException {
for (String include : includes)
findNeeded(include,pending);
}
/**
* Writes out what's spooled by {@link #spool(String...)} method.
*/
public void writeSpooled(XMLOutput out) throws SAXException, IOException {
for (Adjunct adj : pending)
adj.write(request,out);
pending.clear();
}
/**
* Builds up the needed adjuncts into the 'needed' list.
*/
private void findNeeded(String include, List needed) throws IOException {
if(!included.add(include))
return; // already sent
// list dependencies first
try {
Adjunct a = manager.get(include);
for (String req : a.required)
findNeeded(req,needed);
needed.add(a);
} catch (NoSuchAdjunctException e) {
// ignore error
}
}
private static final String KEY = AdjunctsInPage.class.getName();
}