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Jetty web application support
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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.ee8.webapp;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.function.Consumer;
import org.eclipse.jetty.util.TopologicalSort;
import org.eclipse.jetty.util.resource.Resource;
/**
* Relative Fragment Ordering
* Uses a {@link TopologicalSort} to order the fragments.
*/
public class RelativeOrdering implements Ordering {
protected MetaData _metaData;
public RelativeOrdering(MetaData metaData) {
_metaData = metaData;
}
@Override
public List order(List jars) {
TopologicalSort sort = new TopologicalSort<>();
List sorted = new ArrayList<>(jars);
Set others = new HashSet<>();
Set beforeOthers = new HashSet<>();
Set afterOthers = new HashSet<>();
// Pass 1: split the jars into 'before others', 'others' or 'after others'
for (Resource jar : jars) {
FragmentDescriptor fragment = _metaData.getFragmentDescriptorForJar(jar);
if (fragment == null)
others.add(jar);
else {
switch(fragment.getOtherType()) {
case None:
others.add(jar);
break;
case Before:
beforeOthers.add(jar);
break;
case After:
afterOthers.add(jar);
break;
default:
throw new IllegalStateException(fragment.toString());
}
}
}
// Pass 2: Add sort dependencies for each jar
Set referenced = new HashSet<>();
for (Resource jar : jars) {
FragmentDescriptor fragment = _metaData.getFragmentDescriptorForJar(jar);
if (fragment != null) {
// Add each explicit 'after' ordering as a sort dependency
// and remember that the dependency has been referenced.
for (String name : fragment.getAfters()) {
Resource after = _metaData.getJarForFragmentName(name);
sort.addDependency(jar, after);
referenced.add(after);
}
// Add each explicit 'before' ordering as a sort dependency
// and remember that the dependency has been referenced.
for (String name : fragment.getBefores()) {
Resource before = _metaData.getJarForFragmentName(name);
sort.addDependency(before, jar);
referenced.add(before);
}
// handle the others
switch(fragment.getOtherType()) {
case None:
break;
case Before:
// Add a dependency on this jar from all
// jars in the 'others' and 'after others' sets, but
// exclude any jars we have already explicitly
// referenced above.
Consumer addBefore = other -> {
if (!referenced.contains(other))
sort.addDependency(other, jar);
};
others.forEach(addBefore);
afterOthers.forEach(addBefore);
break;
case After:
// Add a dependency from this jar to all
// jars in the 'before others' and 'others' sets, but
// exclude any jars we have already explicitly
// referenced above.
Consumer addAfter = other -> {
if (!referenced.contains(other))
sort.addDependency(jar, other);
};
beforeOthers.forEach(addAfter);
others.forEach(addAfter);
break;
default:
throw new IllegalStateException(fragment.toString());
}
}
referenced.clear();
}
// sort the jars according to the added dependencies
sort.sort(sorted);
return sorted;
}
}