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Java > Open Source Codes > org > eclipse > osgi > internal > resolver > ResolverHelper


1 /*******************************************************************************
2  * Copyright (c) 2003, 2004 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Common Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/cpl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.osgi.internal.resolver;
12
13 import java.util.*;
14 import org.eclipse.core.internal.dependencies.*;
15 import org.eclipse.osgi.service.resolver.*;
16
17 public class ResolverHelper {
18
19     private final static Version NULL_VERSION = new Version(0, 0, 0);
20     private final static IMatchRule GENERAL_MATCHRULE = new GeneralMatchRule();
21
22     static class BundleVersionComparator implements Comparator {
23         public int compare(Object JavaDoc arg0, Object JavaDoc arg1) {
24             Version v1 = (Version) arg0;
25             Version v2 = (Version) arg1;
26             return v1.isGreaterThan(v2) ? 1 : v1.equals(v2) ? 0 : -1;
27         }
28     }
29
30     private final static class GeneralMatchRule implements IMatchRule {
31         public boolean isSatisfied(Object JavaDoc constraint, Object JavaDoc available) {
32             return ((VersionConstraint) constraint).isSatisfiedBy((Version) available);
33         }
34
35         public String JavaDoc toString() {
36             return "general"; //$NON-NLS-1$
37 }
38     }
39
40     public static Element createElement(BundleDescription bundleDescription, DependencySystem system) {
41         String JavaDoc name = getSymbolicName(bundleDescription);
42         Version version = getVersion(bundleDescription);
43         return system.createElement(name, version, createPrerequisites(bundleDescription, system), bundleDescription.isSingleton(), bundleDescription);
44     }
45
46     private static Version getVersion(BundleDescription bundleDescription) {
47         Version version = bundleDescription.getVersion();
48         if (version == null)
49             version = Version.emptyVersion;
50         return version;
51     }
52
53     private static String JavaDoc getSymbolicName(BundleDescription bundleDescription) {
54         String JavaDoc name = bundleDescription.getSymbolicName();
55         // TODO do we still need to return the number as the name if there is no name?
56 if (name == null)
57             // could not be null
58 name = Long.toString(bundleDescription.getBundleId());
59         return name;
60     }
61
62     private static Dependency[] createPrerequisites(BundleDescription bundleDesc, DependencySystem system) {
63         BundleSpecification[] required = bundleDesc.getRequiredBundles();
64         HostSpecification host = bundleDesc.getHost();
65         int dependencyCount = required == null ? 0 : required.length;
66         if (host != null)
67             dependencyCount++;
68         if (dependencyCount == 0)
69             return new Dependency[0];
70         List prereqs = new ArrayList(dependencyCount);
71         for (int i = 0; i < required.length; i++)
72             // ignore if a bundle requires itself (bug 48568 comment 2)
73 if (!required[i].getName().equals(bundleDesc.getSymbolicName()))
74                 prereqs.add(createPrerequisite(system, required[i]));
75         if (host != null)
76             prereqs.add(createPrerequisite(system, host));
77         return (Dependency[]) prereqs.toArray(new Dependency[prereqs.size()]);
78     }
79
80     private static Dependency createPrerequisite(DependencySystem system, VersionConstraint constraint) {
81         boolean optional = (constraint instanceof BundleSpecification) && ((BundleSpecification) constraint).isOptional();
82         return system.createDependency(constraint.getName(), GENERAL_MATCHRULE, optional, constraint);
83     }
84
85     public static DependencySystem createDependencySystem(ISelectionPolicy policy) {
86         return new DependencySystem(new ResolverHelper.BundleVersionComparator(), policy);
87     }
88
89     public static DependencySystem buildDependencySystem(State state, ISelectionPolicy selectionPolicy) {
90         DependencySystem dependencySystem = createDependencySystem(selectionPolicy);
91         BundleDescription[] bundles = state.getBundles();
92         for (int i = 0; i < bundles.length; i++)
93             dependencySystem.addElement(ResolverHelper.createElement(bundles[i], dependencySystem));
94         return dependencySystem;
95     }
96
97     public static void remove(BundleDescription description, DependencySystem system) {
98         system.removeElement(getSymbolicName(description), getVersion(description));
99     }
100
101     public static void add(BundleDescription description, DependencySystem system) {
102         system.addElement(createElement(description, system));
103     }
104
105     public static void unresolve(BundleDescription bundle, DependencySystem system) {
106         Element element = system.getElement(getSymbolicName(bundle), getVersion(bundle));
107         if (element != null)
108             system.unresolve(new Element[] {element});
109     }
110
111     public static void update(BundleDescription newDescription, BundleDescription existing, DependencySystem system) {
112         system.removeElement(getSymbolicName(existing), getVersion(existing));
113         system.addElement(createElement(newDescription, system));
114     }
115 }
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