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java/org/apache/naming/factory/ResourceLinkFactory.java

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+/*
+ * 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.factory;
+
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import javax.naming.Context;
+import javax.naming.Name;
+import javax.naming.NamingException;
+import javax.naming.RefAddr;
+import javax.naming.Reference;
+import javax.naming.spi.ObjectFactory;
+
+import org.apache.naming.ResourceLinkRef;
+import org.apache.naming.StringManager;
+
+/**
+ * <p>Object factory for resource links.</p>
+ *
+ * @author Remy Maucherat
+ */
+public class ResourceLinkFactory implements ObjectFactory {
+
+    // ------------------------------------------------------- Static Variables
+
+    protected static final StringManager sm = StringManager.getManager(ResourceLinkFactory.class);
+
+    /**
+     * Global naming context.
+     */
+    private static Context globalContext = null;
+
+    private static Map<ClassLoader,Map<String,String>> globalResourceRegistrations =
+            new ConcurrentHashMap<>();
+
+    // --------------------------------------------------------- Public Methods
+
+    /**
+     * Set the global context (note: can only be used once).
+     *
+     * @param newGlobalContext new global context value
+     */
+    public static void setGlobalContext(Context newGlobalContext) {
+        SecurityManager sm = System.getSecurityManager();
+        if (sm != null) {
+            sm.checkPermission(new RuntimePermission(
+                   ResourceLinkFactory.class.getName() + ".setGlobalContext"));
+        }
+        globalContext = newGlobalContext;
+    }
+
+
+    public static void registerGlobalResourceAccess(Context globalContext, String localName,
+            String globalName) {
+        validateGlobalContext(globalContext);
+        ClassLoader cl = Thread.currentThread().getContextClassLoader();
+        Map<String,String> registrations = globalResourceRegistrations.get(cl);
+        if (registrations == null) {
+            // Web application initialization is single threaded so this is
+            // safe.
+            registrations = new HashMap<>();
+            globalResourceRegistrations.put(cl, registrations);
+        }
+        registrations.put(localName, globalName);
+    }
+
+
+    public static void deregisterGlobalResourceAccess(Context globalContext, String localName) {
+        validateGlobalContext(globalContext);
+        ClassLoader cl = Thread.currentThread().getContextClassLoader();
+        Map<String,String> registrations = globalResourceRegistrations.get(cl);
+        if (registrations != null) {
+            registrations.remove(localName);
+        }
+    }
+
+
+    public static void deregisterGlobalResourceAccess(Context globalContext) {
+        validateGlobalContext(globalContext);
+        ClassLoader cl = Thread.currentThread().getContextClassLoader();
+        globalResourceRegistrations.remove(cl);
+    }
+
+
+    private static void validateGlobalContext(Context globalContext) {
+        if (ResourceLinkFactory.globalContext != null &&
+                ResourceLinkFactory.globalContext != globalContext) {
+            throw new SecurityException(sm.getString("resourceLinkFactory.invalidGlobalContext"));
+        }
+    }
+
+
+    private static boolean validateGlobalResourceAccess(String globalName) {
+        ClassLoader cl = Thread.currentThread().getContextClassLoader();
+        while (cl != null) {
+            Map<String,String> registrations = globalResourceRegistrations.get(cl);
+            if (registrations != null && registrations.containsValue(globalName)) {
+                return true;
+            }
+            cl = cl.getParent();
+        }
+        return false;
+    }
+
+
+    // -------------------------------------------------- ObjectFactory Methods
+
+    /**
+     * Create a new DataSource instance.
+     *
+     * @param obj The reference object describing the DataSource
+     */
+    @Override
+    public Object getObjectInstance(Object obj, Name name, Context nameCtx,
+            Hashtable<?,?> environment) throws NamingException {
+
+        if (!(obj instanceof ResourceLinkRef)) {
+            return null;
+        }
+
+        // Can we process this request?
+        Reference ref = (Reference) obj;
+
+        // Read the global ref addr
+        String globalName = null;
+        RefAddr refAddr = ref.get(ResourceLinkRef.GLOBALNAME);
+        if (refAddr != null) {
+            globalName = refAddr.getContent().toString();
+            // Confirm that the current web application is currently configured
+            // to access the specified global resource
+            if (!validateGlobalResourceAccess(globalName)) {
+                return null;
+            }
+            Object result = null;
+            result = globalContext.lookup(globalName);
+            // Check the expected type
+            String expectedClassName = ref.getClassName();
+            if (expectedClassName == null) {
+                throw new IllegalArgumentException(
+                        sm.getString("resourceLinkFactory.nullType", name, globalName));
+            }
+            try {
+                Class<?> expectedClazz = Class.forName(
+                        expectedClassName, true, Thread.currentThread().getContextClassLoader());
+                if (!expectedClazz.isAssignableFrom(result.getClass())) {
+                    throw new IllegalArgumentException(sm.getString("resourceLinkFactory.wrongType",
+                            name, globalName, expectedClassName, result.getClass().getName()));
+                }
+            } catch (ClassNotFoundException e) {
+                throw new IllegalArgumentException(sm.getString("resourceLinkFactory.unknownType",
+                        name, globalName, expectedClassName), e);
+            }
+            return result;
+        }
+
+        return null;
+    }
+}