<import> task.

This is almost the same as in embed, except few simplifications
and cleanups.

PR:
Obtained from:
Submitted by:
Reviewed by:


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273687 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/ImportTask.java

@@ -0,0 +1,152 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.taskdefs;
+
+import org.apache.tools.ant.*;
+import org.apache.tools.ant.helper.ProjectHelper2;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * EXPERIMENTAL
+ * Import task.
+ *
+ * It must be 'top level'. On execution it'll read another file
+ * into the same Project.
+ *
+ * Important: there is one limitation related with the top level
+ * elements in the imported files. The current implementation will
+ * add them at the end of the top-level ( instead of replacing the
+ * import element - which would be more intuitive ).
+ *
+ *
+ * @author Nicola Ken Barozzi nicolaken@apache.org
+ * @author Dominique Devienne DDevienne@lgc.com
+ * @author Costin Manolache
+ */
+public class ImportTask extends Task {
+    String file;
+
+    public void setFile( String file ) {
+        // I don't think we can use File - different rules
+        // for relative paths.
+        this.file=file;
+    }
+    
+    /**
+     *  This relies on the task order model.
+     *
+     */
+    public void execute() throws BuildException
+    {
+        if (file == null) {
+            throw new BuildException("import requires file attribute");
+        }
+    
+        ProjectHelper2.AntXmlContext context;
+        context=(ProjectHelper2.AntXmlContext)project.getReference("ant.parsing.context");
+
+        context.importlevel++;
+
+        project.log("Importing file "+file +" from "+
+                    context.buildFile.getAbsolutePath() +
+                "( level=" + context.importlevel + " )",
+                    Project.MSG_VERBOSE);
+
+        // Paths are relative to the build file they're imported from,
+        // *not* the current directory (same as entity includes).
+        File importedFile = new File(file);
+        if (!importedFile.isAbsolute()) {
+            importedFile = new File(context.buildFileParent, file);
+        }
+        if (!importedFile.exists()) {
+                throw new BuildException("Cannot find "+file+" imported from "+
+                                         context.buildFile.getAbsolutePath());
+        }
+
+        // Add parent build file to the map to avoid cycles...
+        String parentFilename = getPath(context.buildFile);
+        if (!context.importedFiles.containsKey(parentFilename)) {
+            context.importedFiles.put(parentFilename, context.buildFile);
+        }
+
+        // Make sure we import the file only once
+        String importedFilename = getPath(importedFile);
+        if (context.importedFiles.containsKey(importedFilename)) {
+            project.log("\nSkipped already imported file:\n   "+
+                    importedFilename+"\n",Project.MSG_WARN);
+            context.importlevel--;
+            return;
+        } else {
+            context.importedFiles.put(importedFilename, importedFile);
+        }
+
+        context.ignoreProjectTag=true;
+        context.helper.parse(project, importedFile,
+                new ProjectHelper2.RootHandler(context));
+
+        context.importlevel--;
+    }
+
+    private static String getPath(File file) {
+        try {
+            return file.getCanonicalPath();
+        }
+        catch (IOException e) {
+            return file.getAbsolutePath();
+        }
+    }
+}