org.eclipse.jetty.webapp.Ordering Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.webapp;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.eclipse.jetty.util.resource.Resource;
/**
* Ordering
*
* Ordering options for jars in WEB-INF lib.
*/
public interface Ordering
{
public List order(List fragments);
public boolean isAbsolute ();
public boolean hasOther();
/**
* AbsoluteOrdering
*
* An <absolute-order> element in web.xml
*/
public static class AbsoluteOrdering implements Ordering
{
public static final String OTHER = "@@-OTHER-@@";
protected List _order = new ArrayList();
protected boolean _hasOther = false;
protected MetaData _metaData;
public AbsoluteOrdering (MetaData metaData)
{
_metaData = metaData;
}
/**
* Order the list of jars in WEB-INF/lib according to the ordering declarations in the descriptors
* @see org.eclipse.jetty.webapp.Ordering#order(java.util.List)
*/
@Override
public List order(List jars)
{
List orderedList = new ArrayList();
List tmp = new ArrayList(jars);
//1. put everything into the list of named others, and take the named ones out of there,
//assuming we will want to use the clause
Map others = new HashMap(_metaData.getNamedFragments());
//2. for each name, take out of the list of others, add to tail of list
int index = -1;
for (String item:_order)
{
if (!item.equals(OTHER))
{
FragmentDescriptor f = others.remove(item);
if (f != null)
{
Resource jar = _metaData.getJarForFragment(item);
orderedList.add(jar); //take from others and put into final list in order, ignoring duplicate names
//remove resource from list for resource matching name of descriptor
tmp.remove(jar);
}
}
else
index = orderedList.size(); //remember the index at which we want to add in all the others
}
//3. if was specified, insert rest of the fragments
if (_hasOther)
{
orderedList.addAll((index < 0? 0: index), tmp);
}
return orderedList;
}
@Override
public boolean isAbsolute()
{
return true;
}
public void add (String name)
{
_order.add(name);
}
public void addOthers ()
{
if (_hasOther)
throw new IllegalStateException ("Duplicate element in absolute ordering");
_hasOther = true;
_order.add(OTHER);
}
@Override
public boolean hasOther ()
{
return _hasOther;
}
}
/**
* RelativeOrdering
*
* A set of <order> elements in web-fragment.xmls.
*/
public static class RelativeOrdering implements Ordering
{
protected MetaData _metaData;
protected LinkedList _beforeOthers = new LinkedList();
protected LinkedList _afterOthers = new LinkedList();
protected LinkedList _noOthers = new LinkedList();
public RelativeOrdering (MetaData metaData)
{
_metaData = metaData;
}
/**
* Order the list of jars according to the ordering declared
* in the various web-fragment.xml files.
* @see org.eclipse.jetty.webapp.Ordering#order(java.util.List)
*/
@Override
public List order(List jars)
{
//for each jar, put it into the ordering according to the fragment ordering
for (Resource jar:jars)
{
//check if the jar has a fragment descriptor
FragmentDescriptor descriptor = _metaData.getFragment(jar);
if (descriptor != null)
{
switch (descriptor.getOtherType())
{
case None:
{
((RelativeOrdering)_metaData.getOrdering()).addNoOthers(jar);
break;
}
case Before:
{
((RelativeOrdering)_metaData.getOrdering()).addBeforeOthers(jar);
break;
}
case After:
{
((RelativeOrdering)_metaData.getOrdering()).addAfterOthers(jar);
break;
}
}
}
else
{
//jar fragment has no descriptor, but there is a relative ordering in place, so it must be part of the others
((RelativeOrdering)_metaData.getOrdering()).addNoOthers(jar);
}
}
//now apply the ordering
List orderedList = new ArrayList();
int maxIterations = 2;
boolean done = false;
do
{
//1. order the before-others according to any explicit before/after relationships
boolean changesBefore = orderList(_beforeOthers);
//2. order the after-others according to any explicit before/after relationships
boolean changesAfter = orderList(_afterOthers);
//3. order the no-others according to their explicit before/after relationships
boolean changesNone = orderList(_noOthers);
//we're finished on a clean pass through with no ordering changes
done = (!changesBefore && !changesAfter && !changesNone);
}
while (!done && (--maxIterations >0));
//4. merge before-others + no-others +after-others
if (!done)
throw new IllegalStateException("Circular references for fragments");
for (Resource r: _beforeOthers)
orderedList.add(r);
for (Resource r: _noOthers)
orderedList.add(r);
for(Resource r: _afterOthers)
orderedList.add(r);
return orderedList;
}
@Override
public boolean isAbsolute ()
{
return false;
}
@Override
public boolean hasOther ()
{
return !_beforeOthers.isEmpty() || !_afterOthers.isEmpty();
}
public void addBeforeOthers (Resource r)
{
_beforeOthers.addLast(r);
}
public void addAfterOthers (Resource r)
{
_afterOthers.addLast(r);
}
public void addNoOthers (Resource r)
{
_noOthers.addLast(r);
}
protected boolean orderList (LinkedList list)
{
//Take a copy of the list so we can iterate over it and at the same time do random insertions
boolean changes = false;
List iterable = new ArrayList(list);
Iterator itor = iterable.iterator();
while (itor.hasNext())
{
Resource r = itor.next();
FragmentDescriptor f = _metaData.getFragment(r);
if (f == null)
{
//no fragment for this resource so cannot have any ordering directives
continue;
}
//Handle any explicit relationships for the fragment we're considering
List befores = f.getBefores();
if (befores != null && !befores.isEmpty())
{
for (String b: befores)
{
//Fragment we're considering must be before b
//Check that we are already before it, if not, move us so that we are.
//If the name does not exist in our list, then get it out of the no-other list
if (!isBefore(list, f.getName(), b))
{
//b is not already before name, move it so that it is
int idx1 = getIndexOf(list, f.getName());
int idx2 = getIndexOf(list, b);
//if b is not in the same list
if (idx2 < 0)
{
changes = true;
// must be in the noOthers list or it would have been an error
Resource bResource = _metaData.getJarForFragment(b);
if (bResource != null)
{
//If its in the no-others list, insert into this list so that we are before it
if (_noOthers.remove(bResource))
{
insert(list, idx1+1, b);
}
}
}
else
{
//b is in the same list but b is before name, so swap it around
list.remove(idx1);
insert(list, idx2, f.getName());
changes = true;
}
}
}
}
//Handle any explicit relationships
List afters = f.getAfters();
if (afters != null && !afters.isEmpty())
{
for (String a: afters)
{
//Check that fragment we're considering is after a, moving it if possible if its not
if (!isAfter(list, f.getName(), a))
{
//name is not after a, move it
int idx1 = getIndexOf(list, f.getName());
int idx2 = getIndexOf(list, a);
//if a is not in the same list as name
if (idx2 < 0)
{
changes = true;
//take it out of the noOthers list and put it in the right place in this list
Resource aResource = _metaData.getJarForFragment(a);
if (aResource != null)
{
if (_noOthers.remove(aResource))
{
insert(list,idx1, aResource);
}
}
}
else
{
//a is in the same list as name, but in the wrong place, so move it
list.remove(idx2);
insert(list,idx1, a);
changes = true;
}
}
//Name we're considering must be after this name
//Check we're already after it, if not, move us so that we are.
//If the name does not exist in our list, then get it out of the no-other list
}
}
}
return changes;
}
/**
* Is fragment with name a before fragment with name b?
* @param list
* @param fragNameA
* @param fragNameB
* @return true if fragment name A is before fragment name B
*/
protected boolean isBefore (List list, String fragNameA, String fragNameB)
{
//check if a and b are already in the same list, and b is already
//before a
int idxa = getIndexOf(list, fragNameA);
int idxb = getIndexOf(list, fragNameB);
if (idxb >=0 && idxb < idxa)
{
//a and b are in the same list but a is not before b
return false;
}
if (idxb < 0)
{
//a and b are not in the same list, but it is still possible that a is before
//b, depending on which list we're examining
if (list == _beforeOthers)
{
//The list we're looking at is the beforeOthers.If b is in the _afterOthers or the _noOthers, then by
//definition a is before it
return true;
}
else if (list == _afterOthers)
{
//The list we're looking at is the afterOthers, then a will be the tail of
//the final list. If b is in the beforeOthers list, then b will be before a and an error.
if (_beforeOthers.contains(fragNameB))
throw new IllegalStateException("Incorrect relationship: "+fragNameA+" before "+fragNameB);
else
return false; //b could be moved to the list
}
}
//a and b are in the same list and a is already before b
return true;
}
/**
* Is fragment name "a" after fragment name "b"?
* @param list
* @param fragNameA
* @param fragNameB
* @return true if fragment name A is after fragment name B
*/
protected boolean isAfter(List list, String fragNameA, String fragNameB)
{
int idxa = getIndexOf(list, fragNameA);
int idxb = getIndexOf(list, fragNameB);
if (idxb >=0 && idxa < idxb)
{
//a and b are both in the same list, but a is before b
return false;
}
if (idxb < 0)
{
//a and b are in different lists. a could still be after b depending on which list it is in.
if (list == _afterOthers)
{
//The list we're looking at is the afterOthers. If b is in the beforeOthers or noOthers then
//by definition a is after b because a is in the afterOthers list.
return true;
}
else if (list == _beforeOthers)
{
//The list we're looking at is beforeOthers, and contains a and will be before
//everything else in the final ist. If b is in the afterOthers list, then a cannot be before b.
if (_afterOthers.contains(fragNameB))
throw new IllegalStateException("Incorrect relationship: "+fragNameB+" after "+fragNameA);
else
return false; //b could be moved from noOthers list
}
}
return true; //a and b in the same list, a is after b
}
/**
* Insert the resource matching the fragName into the list of resources
* at the location indicated by index.
*
* @param list
* @param index
* @param fragName
*/
protected void insert(List list, int index, String fragName)
{
Resource jar = _metaData.getJarForFragment(fragName);
if (jar == null)
throw new IllegalStateException("No jar for insertion");
insert(list, index, jar);
}
protected void insert(List list, int index, Resource resource)
{
if (list == null)
throw new IllegalStateException("List is null for insertion");
//add it at the end
if (index > list.size())
list.add(resource);
else
list.add(index, resource);
}
protected void remove (List resources, Resource r)
{
if (resources == null)
return;
resources.remove(r);
}
protected int getIndexOf(List resources, String fragmentName)
{
FragmentDescriptor fd = _metaData.getFragment(fragmentName);
if (fd == null)
return -1;
Resource r = _metaData.getJarForFragment(fragmentName);
if (r == null)
return -1;
return resources.indexOf(r);
}
}
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