DependencyMediator


1   /*
2    * Copyright (c) 2003-2004, Inversoft, All Rights Reserved
3    *
4    * This software is distribuable under the GNU Lesser General Public License.
5    * For more information visit gnu.org.
6    */
7   package com.inversoft.savant;
8   
9   
10  import java.io.File  ;
11  import java.util.ArrayList  ;
12  import java.util.HashMap  ;
13  import java.util.HashSet  ;
14  import java.util.Iterator  ;
15  import java.util.List  ;
16  import java.util.Map  ;
17  import java.util.Set  ;
18  
19  
20  /**
21   * <p>
22   * This is used to iterate over depedency lists (artifacts
23   * and artifact groups) and call out to interested listeners.
24   * </p>
25   *
26   * @author Brian Pontarelli
27   */
28  public class DependencyMediator {
29  
30      private static Set   projectsBuilt = new HashSet  ();
31      private static Map   artifactsFetched = new HashMap  ();
32  
33      private List   listeners = new ArrayList  ();
34      private Dependencies dependencies = new Dependencies();
35      private LocalCacheStore localCacheStore;
36      private Workflow workflow;
37  
38  
39      /**
40       * Creates a new DepedencyMediator.
41       */
42      public DependencyMediator() {
43      }
44  
45  
46      /**
47       * Fetches the local cache location from this mediators {@link LocalCacheStore}.
48       * If the local cache hasn't been constructed, this returns null.
49       */
50      public File   getLocalCacheDir() {
51          return (localCacheStore == null) ? null : localCacheStore.getLocation();
52      }
53  
54      /**
55       * Sets the local cache location for this mediators {@link LocalCacheStore}.
56       *
57       * @param   localCacheDir The directory that is used as the LocalCacheStore
58       *          location
59       * @throws  SavantException If the File given is invalid
60       */
61      public void setLocalCacheDir(File   localCacheDir) throws SavantException {
62          this.localCacheStore = new LocalCacheStore(localCacheDir);
63      }
64  
65      /**
66       * Adds the given listener from the list of lisetners.
67       *
68       * @param   listener The listener to add
69       */
70      public void addListener(DependencyListener listener) {
71          listeners.add(listener);
72      }
73  
74      /**
75       * Removes the given listener from the list of lisetners.
76       *
77       * @param   listener The listener to remove
78       */
79      public void removeListener(DependencyListener listener) {
80          listeners.remove(listener);
81      }
82  
83      /**
84       * Fetches the dependencies that will be mediated over during mediation.
85       *
86       * @return  The {@link Dependencies} object or null if one was never set
87       */
88      public Dependencies getDependencies() {
89          return dependencies;
90      }
91  
92      /**
93       * Sets the dependencies that will be mediated over during mediation.
94       *
95       * @param   dependencies The new dependencies to mediate over
96       */
97      public void setDependencies(Dependencies dependencies) {
98          this.dependencies = dependencies;
99      }
100 
101     /**
102      * Retrieves the workflow.
103      */
104     public Workflow getWorkflow() {
105         return workflow;
106     }
107 
108     /**
109      * Sets the workflow.
110      */
111     public void setWorkflow(Workflow workflow) {
112         this.workflow = workflow;
113     }
114 
115     /**
116      * Executes this task that builds up the dependencies and such.
117      */
118     public void mediate() throws SavantException {
119         workflow.validate();
120 
121         handleGroups(dependencies.getArtifactGroups());
122 
123         Iterator   aIter = dependencies.getArtifacts().iterator();
124         while (aIter.hasNext()) {
125             Artifact artifact = (Artifact) aIter.next();
126             handleArtifact(artifact, null);
127         }
128     }
129 
130     /**
131      * Handles iteration over ArtifactGroups. This calls the
132      * {@link #handleArtifact(Artifact, ArtifactGroup)} for each artifact in the
133      * group and then recurses for each ArtifactGroup in the group.
134      *
135      * @param   groups The groups to retrieve the artifacts and sub-groups from
136      * @throws  SavantException If the mediation failed for any reason
137      */
138     protected void handleGroups(List   groups) throws SavantException {
139         // Loop over all the artifact group and try to fetch the artifacts
140         for (int i = 0; i < groups.size(); i++) {
141             ArtifactGroup group = (ArtifactGroup) groups.get(i);
142             List   artifacts = group.getArtifacts();
143             for (int j = 0; j < artifacts.size(); j++) {
144                 Artifact artifact = (Artifact) artifacts.get(j);
145                 handleArtifact(artifact, group);
146             }
147 
148             List   subGroups = group.getArtifactGroups();
149             if (subGroups.size() > 0) {
150                 handleGroups(subGroups);
151             }
152         }
153     }
154 
155     /**
156      * Handles the fetching of a single artifact. This method also optionally takes
157      * a file set and path (classpath) that the artifact is added to. If these
158      * are null, they are ignored.
159      *
160      * @param   artifact The artifact to fetch and store
161      */
162     protected void handleArtifact(Artifact artifact, ArtifactGroup group)
163     throws SavantException {
164         // Setup the dependencies (if any)
165         workflow.resolveArtifactDependencies(artifact, localCacheStore);
166 
167         // Go find the file and build the projects
168         File   file = (File  ) artifactsFetched.get(artifact);
169         if (file == null) {
170             String   artifactProject = artifact.getProjectname();
171             String   artifactGroup = artifact.getGroup();
172 
173             // Figure out if this project is local and if so, build it
174             String   projectID = LocalProject.makeProjectID(artifactGroup,
175                 artifactProject);
176             LocalProject project = dependencies.getProject(projectID);
177             if (project != null && !projectsBuilt.contains(project)) {
178                 project.build();
179                 projectsBuilt.add(project);
180 
181                 for (int i = 0; i < listeners.size(); i++) {
182                     DependencyListener listener = (DependencyListener) listeners.get(i);
183                     listener.projectBuilt(project);
184                 }
185             }
186 
187             // Let the workflow handle the resolution from both the local cache and
188             // the process objects.
189             file = workflow.findArtifact(artifact, localCacheStore);
190             if (file == null) {
191                 throw new SavantException("Unable to locate dependency [" +
192                     artifact.toString() + "]");
193             }
194 
195             artifactsFetched.put(artifact, file);
196         }
197 
198         for (int i = 0; i < listeners.size(); i++) {
199             DependencyListener listener = (DependencyListener) listeners.get(i);
200             listener.artifactFound(file, artifact, group);
201         }
202 
203         // Recurse to handle the dependencies of the artifact
204         List   deps = artifact.getDependencies();
205         if (deps.size() > 0) {
206             for (int i = 0; i < deps.size(); i++) {
207                 handleArtifact((Artifact) deps.get(i), group);
208             }
209         }
210     }
211 }
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