(no commit message)
authorerik <erik@77661180-640e-0410-b3a8-9f9b13e6d0e0>
Tue, 22 Jun 2010 20:37:19 +0000 (20:37 +0000)
committererik <erik@77661180-640e-0410-b3a8-9f9b13e6d0e0>
Tue, 22 Jun 2010 20:37:19 +0000 (20:37 +0000)
support/general/src/main/java/org/wamblee/ioc/BeanFactory.java [new file with mode: 0644]
support/general/src/main/java/org/wamblee/ioc/BeanFactoryException.java [new file with mode: 0644]
support/general/src/main/java/org/wamblee/ioc/BeanKernel.java [new file with mode: 0644]

diff --git a/support/general/src/main/java/org/wamblee/ioc/BeanFactory.java b/support/general/src/main/java/org/wamblee/ioc/BeanFactory.java
new file mode 100644 (file)
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--- /dev/null
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2005-2010 the original author or authors.
+ * 
+ * Licensed 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.wamblee.ioc;
+
+/**
+ * Bean factory used to obtain objects in a transparent way.
+ * 
+ * @author Erik Brakkee
+ */
+public interface BeanFactory {
+    /**
+     * Finds a bean based on id.
+     * 
+     * @param aId
+     *            Id of the bean.
+     * @return Object (always non-null).
+     * @throws BeanFactoryException
+     *             In case the object could not be found.
+     */
+    Object find(String aId);
+
+    <T> T find(Class<T> aClass);
+
+    <T> T find(String aId, Class<T> aClass);
+}
diff --git a/support/general/src/main/java/org/wamblee/ioc/BeanFactoryException.java b/support/general/src/main/java/org/wamblee/ioc/BeanFactoryException.java
new file mode 100644 (file)
index 0000000..e56c1a9
--- /dev/null
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2005-2010 the original author or authors.
+ * 
+ * Licensed 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.wamblee.ioc;
+
+/**
+ * Exception thrown by the BeanFactory if an object could not be found.
+ * 
+ * @author Erik Brakkee
+ */
+public class BeanFactoryException extends RuntimeException {
+    static final long serialVersionUID = -1215992188624874902L;
+
+    /**
+     * Constructs the exception.
+     * 
+     * @param aMsg
+     *            Message.
+     */
+    public BeanFactoryException(String aMsg) {
+        super(aMsg);
+    }
+
+    /**
+     * Constructs the exception.
+     * 
+     * @param aMsg
+     *            Message.
+     * @param aThrowable
+     *            Cause of the exception.
+     */
+    public BeanFactoryException(String aMsg, Throwable aThrowable) {
+        super(aMsg, aThrowable);
+    }
+}
diff --git a/support/general/src/main/java/org/wamblee/ioc/BeanKernel.java b/support/general/src/main/java/org/wamblee/ioc/BeanKernel.java
new file mode 100644 (file)
index 0000000..3118b5d
--- /dev/null
@@ -0,0 +1,127 @@
+/*
+ * Copyright 2005-2010 the original author or authors.
+ * 
+ * Licensed 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.wamblee.ioc;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.wamblee.io.ClassPathResource;
+import org.wamblee.io.InputResource;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import java.util.Properties;
+
+/**
+ * The standard means to obtain the bean factory. This works by reading a
+ * property {@value #BEAN_FACTORY_CLASS} from a property file named
+ * {@value #BEAN_KERNEL_PROP_FILE} from the class path. This property identifies
+ * the bean factory implementation to use. The configured bean factory must have
+ * a no-arg constructor.
+ */
+public final class BeanKernel {
+    private static final Log LOG = LogFactory.getLog(BeanKernel.class);
+
+    /**
+     * Bean factory kernel properties file.
+     */
+    private static final String BEAN_KERNEL_PROP_FILE = "org.wamblee.beanfactory.properties";
+
+    /**
+     * Name of the property to define the name of the bean factory class to use.
+     * THis class must have a public default constructor.
+     */
+    private static final String BEAN_FACTORY_CLASS = "org.wamblee.beanfactory.class";
+
+    /**
+     * Cached bean factory.
+     */
+    private static BeanFactory BEAN_FACTORY;
+
+    /**
+     * Disabled constructor.
+     * 
+     */
+    private BeanKernel() {
+        // Empty
+    }
+
+    /**
+     * Overrides the default mechanism for looking up the bean factory by
+     * specifying it yourself.
+     * 
+     * @param aOverride
+     *            Override bean factory.
+     */
+    public static void overrideBeanFactory(BeanFactory aOverride) {
+        BEAN_FACTORY = aOverride;
+    }
+
+    /**
+     * Gets the bean factory.
+     * 
+     * @return Bean factory.
+     */
+    public static BeanFactory getBeanFactory() {
+        synchronized (BeanFactory.class) {
+            if (BEAN_FACTORY == null) {
+                BEAN_FACTORY = lookupBeanFactory(BEAN_KERNEL_PROP_FILE);
+            }
+        }
+
+        return BEAN_FACTORY;
+    }
+
+    /**
+     * Lookup the bean factory based on the properties file.
+     * 
+     * 
+     * @return Bean factory.
+     * 
+     */
+    static BeanFactory lookupBeanFactory(String aPropertyFilename) {
+        InputResource resource = new ClassPathResource(aPropertyFilename);
+        InputStream is;
+
+        try {
+            is = resource.getInputStream();
+        } catch (IOException e) {
+            throw new BeanFactoryException("Cannot open resource " + resource,
+                e);
+        }
+
+        try {
+            Properties props = new Properties();
+            props.load(is);
+
+            String className = props.getProperty(BEAN_FACTORY_CLASS);
+            Class beanFactory = Class.forName(className);
+
+            return (BeanFactory) beanFactory.newInstance();
+        } catch (Exception e) {
+            throw new BeanFactoryException("Cannot read from resource " +
+                resource, e);
+        } finally {
+            try {
+                is.close();
+            } catch (IOException e) {
+                // last resort cannot do much now.
+                LOG.error("Error closing resource " + resource);
+            }
+        }
+    }
+}