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Java > Open Source Codes > org > apache > tools > ant > taskdefs > ImportTask


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3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  */
18
19 package org.apache.tools.ant.taskdefs;
20
21 import org.apache.tools.ant.BuildException;
22 import org.apache.tools.ant.ProjectHelper;
23 import org.apache.tools.ant.Project;
24 import org.apache.tools.ant.Task;
25 import org.apache.tools.ant.util.FileUtils;
26
27 import java.io.File JavaDoc;
28 import java.util.Vector JavaDoc;
29
30 /**
31  * Task to import another build file into the current project.
32  * <p>
33  * It must be 'top level'. On execution it will read another Ant file
34  * into the same Project.
35  * </p>
36  * <p>
37  * <b>Important</b>: we have not finalized how relative file references
38  * will be resolved in deep/complex build hierarchies - such as what happens
39  * when an imported file imports another file. Use absolute references for
40  * enhanced build file stability, especially in the imported files.
41  * </p>
42  * <p>Examples:</p>
43  * <pre>
44  * &lt;import file="../common-targets.xml"/&gt;
45  * </pre>
46  * <p>Import targets from a file in a parent directory.</p>
47  * <pre>
48  * &lt;import file="${deploy-platform}.xml"/&gt;
49  * </pre>
50  * <p>Import the project defined by the property <code>deploy-platform</code>.</p>
51  *
52  * @since Ant1.6
53  * @ant.task category="control"
54  */
55 public class ImportTask extends Task {
56     private String JavaDoc file;
57     private boolean optional;
58     private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
59
60     /**
61      * sets the optional attribute
62      *
63      * @param optional if true ignore files that are not present,
64      * default is false
65      */
66     public void setOptional(boolean optional) {
67         this.optional = optional;
68     }
69
70     /**
71      * the name of the file to import. How relative paths are resolved is still
72      * in flux: use absolute paths for safety.
73      * @param file the name of the file
74      */
75     public void setFile(String JavaDoc file) {
76         // I don't think we can use File - different rules
77 // for relative paths.
78 this.file = file;
79     }
80
81     /**
82      * This relies on the task order model.
83      *
84      */
85     public void execute() {
86         if (file == null) {
87             throw new BuildException("import requires file attribute");
88         }
89         if (getOwningTarget() == null
90             || !"".equals(getOwningTarget().getName())) {
91             throw new BuildException("import only allowed as a top-level task");
92         }
93
94         ProjectHelper helper =
95                 (ProjectHelper) getProject().
96                     getReference(ProjectHelper.PROJECTHELPER_REFERENCE);
97
98         if (helper == null) {
99             // this happens if the projecthelper was not registered with the project.
100 throw new BuildException("import requires support in ProjectHelper");
101         }
102
103         Vector JavaDoc importStack = helper.getImportStack();
104
105         if (importStack.size() == 0) {
106             // this happens if ant is used with a project
107 // helper that doesn't set the import.
108 throw new BuildException("import requires support in ProjectHelper");
109         }
110
111         if (getLocation() == null || getLocation().getFileName() == null) {
112             throw new BuildException("Unable to get location of import task");
113         }
114
115         File JavaDoc buildFile = new File JavaDoc(getLocation().getFileName()).getAbsoluteFile();
116
117         // Paths are relative to the build file they're imported from,
118 // *not* the current directory (same as entity includes).
119
120         File JavaDoc buildFileParent = new File JavaDoc(buildFile.getParent());
121         File JavaDoc importedFile = FILE_UTILS.resolveFile(buildFileParent, file);
122
123         getProject().log("Importing file " + importedFile + " from "
124                          + buildFile.getAbsolutePath(), Project.MSG_VERBOSE);
125
126         if (!importedFile.exists()) {
127             String JavaDoc message =
128                 "Cannot find " + file + " imported from "
129                 + buildFile.getAbsolutePath();
130             if (optional) {
131                 getProject().log(message, Project.MSG_VERBOSE);
132                 return;
133             } else {
134                 throw new BuildException(message);
135             }
136         }
137
138         if (importStack.contains(importedFile)) {
139             getProject().log(
140                 "Skipped already imported file:\n "
141                 + importedFile + "\n", Project.MSG_VERBOSE);
142             return;
143         }
144
145         try {
146             helper.parse(getProject(), importedFile);
147         } catch (BuildException ex) {
148             throw ProjectHelper.addLocationToBuildException(
149                 ex, getLocation());
150         }
151     }
152
153 }
154
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