http://issues.apache.org/bugzilla/show_bug.cgi?id=41260

[Contribution] WebAppLoader and DirContext implementations
for handling with expanded webapp during development

 by Fabrizio Giustina

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc6.0.x/trunk@491995 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/java/org/apache/catalina/loader/VirtualWebappLoader.java b/java/org/apache/catalina/loader/VirtualWebappLoader.java
new file mode 100755 (executable)
index 0000000..d58bb70
--- /dev/null
+++ b/java/org/apache/catalina/loader/VirtualWebappLoader.java
@@ -0,0 +1,96 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.catalina.loader;
+
+import java.io.File;
+import java.util.StringTokenizer;
+
+import org.apache.catalina.LifecycleException;
+
+/**
+ * Simple webapp classloader that allows a customized classpath to be added
+ * through configuration in context xml. Any additional classpath entry will be
+ * added to the default webapp classpath, making easy to emulate a standard
+ * webapp without the need for assembly all the webapp dependencies as jars in
+ * WEB-INF/lib.
+ *
+ * <code>
+ * &lt;Context docBase="\webapps\mydocbase">
+ *   &lt;Loader className="org.apache.catalina.loader.VirtualWebappLoader"
+ *              virtualClasspath="\dir\classes;\somedir\somejar.jar"/>
+ * &lt;/Context>
+ * </code>
+ * @author Fabrizio Giustina
+ * @version $Id: $
+ */
+public class VirtualWebappLoader extends WebappLoader {
+
+    /**
+     * <code>;</code> separated list of additional path elements.
+     */
+    private String virtualClasspath;
+
+    /**
+     * Construct a new WebappLoader with no defined parent class loader (so that
+     * the actual parent will be the system class loader).
+     */
+    public VirtualWebappLoader() {
+        super();
+    }
+
+    /**
+     * Construct a new WebappLoader with the specified class loader to be
+     * defined as the parent of the ClassLoader we ultimately create.
+     *
+     * @param parent The parent class loader
+     */
+    public VirtualWebappLoader(ClassLoader parent) {
+        super(parent);
+    }
+
+    /**
+     * <code>virtualClasspath</code> attribute that will be automatically set
+     * from the <code>Context</code> <code>virtualClasspath</code> attribute
+     * from the context xml file.
+     * @param path <code>;</code> separated list of path elements.
+     */
+    public void setVirtualClasspath(String path) {
+        virtualClasspath = path;
+    }
+
+    @Override
+    public void start() throws LifecycleException {
+
+        // just add any jar/directory set in virtual classpath to the
+        // repositories list before calling start on the standard WebappLoader
+        StringTokenizer tkn = new StringTokenizer(virtualClasspath, ";");
+        while (tkn.hasMoreTokens()) {
+            File file = new File(tkn.nextToken());
+            if (!file.exists()) {
+                continue;
+            }
+            if (file.isDirectory()) {
+                addRepository("file:/" + file.getAbsolutePath() + "/");
+            } else {
+                addRepository("file:/" + file.getAbsolutePath());
+            }
+        }
+
+        super.start();
+    }
+
+}

diff --git a/java/org/apache/naming/resources/VirtualDirContext.java b/java/org/apache/naming/resources/VirtualDirContext.java
new file mode 100755 (executable)
index 0000000..fef63a4
--- /dev/null
+++ b/java/org/apache/naming/resources/VirtualDirContext.java
@@ -0,0 +1,186 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.naming.resources;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Hashtable;
+import java.util.List;
+import java.util.Map;
+import java.util.StringTokenizer;
+
+import javax.naming.NamingException;
+import javax.naming.directory.Attributes;
+
+import org.apache.naming.NamingEntry;
+
+/**
+ * Extended FileDirContext implementation that will allow loading of tld files
+ * from the META-INF directory (or subdirectories) in classpath. This will fully
+ * mimic the behavior of compressed jars also when using unjarred resources. Tld
+ * files can be loaded indifferently from WEB-INF webapp dir (or subdirs) or
+ * from META-INF dir from jars available in the classpath: using this DirContext
+ * implementation you will be able to use unexpanded jars during development and
+ * to make any tld in them virtually available to the webapp.
+ *
+ * Sample context xml configuration:
+ *
+ * <code>
+ * &lt;Context docBase="\webapps\mydocbase">
+ *   &lt;Resources className="org.apache.naming.resources.VirtualDirContext"
+ *              virtualClasspath="\dir\classes;\somedir\somejar.jar"/>
+ * &lt;/Resources>
+ * </code>
+ * @author Fabrizio Giustina
+ * @version $Id: $
+ */
+public class VirtualDirContext extends FileDirContext {
+
+    /**
+     * Map containing generated virtual names for tld files under WEB-INF and
+     * the actual file reference.
+     */
+    private Map<String, File> virtualMappings;
+
+    /**
+     * <code>;</code> separated list of virtual path elements.
+     */
+    private String virtualClasspath;
+
+    /**
+     * <code>virtualClasspath</code> attribute that will be automatically set
+     * from the <code>Context</code> <code>virtualClasspath</code> attribute
+     * from the context xml file.
+     * @param path <code>;</code> separated list of path elements.
+     */
+    public void setVirtualClasspath(String path) {
+        virtualClasspath = path;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void allocate() {
+        super.allocate();
+
+        virtualMappings = new Hashtable<String, File>();
+
+        // looks into any META-INF dir found in classpath entries for tld files.
+        StringTokenizer tkn = new StringTokenizer(virtualClasspath, ";");
+        while (tkn.hasMoreTokens()) {
+            File file = new File(tkn.nextToken(), "META-INF");
+
+            if (!file.exists() || !file.isDirectory()) {
+                continue;
+            }
+            scanForTlds(file);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void release() {
+        super.release();
+        virtualMappings = null;
+    }
+
+    @Override
+    public Attributes getAttributes(String name) throws NamingException {
+
+        // handle "virtual" tlds
+        if (name.startsWith("/WEB-INF/") && name.endsWith(".tld")) {
+            String tldName = name.substring(name.lastIndexOf("/") + 1);
+            if (virtualMappings.containsKey(tldName)) {
+                return new FileResourceAttributes(virtualMappings.get(tldName));
+            }
+        }
+
+        return super.getAttributes(name);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    protected ArrayList list(File file) {
+        ArrayList entries = super.list(file);
+
+        // adds virtual tlds for WEB-INF listing
+        if ("WEB-INF".equals(file.getName())) {
+            entries.addAll(getVirtualNamingEntries());
+        }
+
+        return entries;
+    }
+
+    @Override
+    public Object lookup(String name) throws NamingException {
+
+        // handle "virtual" tlds
+        if (name.startsWith("/WEB-INF/") && name.endsWith(".tld")) {
+            String tldName = name.substring(name.lastIndexOf("/") + 1);
+            if (virtualMappings.containsKey(tldName)) {
+                return new FileResource(virtualMappings.get(tldName));
+            }
+        }
+
+        return super.lookup(name);
+    }
+
+    /**
+     * Scan a given dir for tld files. Any found tld will be added to the
+     * virtualMappings.
+     * @param dir Dir to scan for tlds
+     */
+    private void scanForTlds(File dir) {
+
+        File[] files = dir.listFiles();
+        for (int j = 0; j < files.length; j++) {
+            File file = files[j];
+
+            if (file.isDirectory()) {
+                scanForTlds(file);
+            } else if (file.getName().endsWith(".tld")) {
+                // just generate a random name using the current timestamp, name
+                // doesn't matter since it needs to be referenced by URI
+                String virtualTldName = "~" + System.currentTimeMillis() + "~"
+                        + file.getName();
+                virtualMappings.put(virtualTldName, file);
+            }
+        }
+
+    }
+
+    /**
+     * Returns a list of virtual naming entries.
+     * @return list of naming entries, containing tlds in virtualMappings
+     */
+    private List<NamingEntry> getVirtualNamingEntries() {
+        List<NamingEntry> virtual = new ArrayList<NamingEntry>();
+
+        for (String name : virtualMappings.keySet()) {
+
+            File file = virtualMappings.get(name);
+            NamingEntry entry = new NamingEntry(name, new FileResource(file),
+                    NamingEntry.ENTRY);
+            virtual.add(entry);
+        }
+        return virtual;
+    }
+
+}