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Posted to commits@commons.apache.org by oh...@apache.org on 2012/10/09 22:16:22 UTC

svn commit: r1396291 - in /commons/proper/configuration/trunk/src: main/java/org/apache/commons/configuration/builder/FileBasedConfigurationBuilder.java test/java/org/apache/commons/configuration/builder/TestFileBasedConfigurationBuilder.java

Author: oheger
Date: Tue Oct  9 20:16:20 2012
New Revision: 1396291

URL: http://svn.apache.org/viewvc?rev=1396291&view=rev
Log:
Added FileBasedConfigurationBuilder class.

Added:
    commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/builder/FileBasedConfigurationBuilder.java   (with props)
    commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/builder/TestFileBasedConfigurationBuilder.java   (with props)

Added: commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/builder/FileBasedConfigurationBuilder.java
URL: http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/builder/FileBasedConfigurationBuilder.java?rev=1396291&view=auto
==============================================================================
--- commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/builder/FileBasedConfigurationBuilder.java (added)
+++ commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/builder/FileBasedConfigurationBuilder.java Tue Oct  9 20:16:20 2012
@@ -0,0 +1,164 @@
+/*
+ * 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.commons.configuration.builder;
+
+import java.util.Map;
+
+import org.apache.commons.configuration.ConfigurationException;
+import org.apache.commons.configuration.FileBasedConfiguration;
+import org.apache.commons.configuration.io.FileHandler;
+
+/**
+ * <p>
+ * A specialized {@code ConfigurationBuilder} implementation which can handle
+ * configurations read from a {@link FileHandler}.
+ * </p>
+ * <p>
+ * This class extends its base class by the support of a
+ * {@link FileBasedBuilderParameters} object, and especially of the
+ * {@link FileHandler} contained in this object. When the builder creates a new
+ * object the resulting {@code Configuration} instance is associated with the
+ * {@code FileHandler}. If the {@code FileHandler} has a location set, the
+ * {@code Configuration} is directly loaded from this location.
+ * </p>
+ * <p>
+ * The {@code FileHandler} is kept by this builder and can be queried later on.
+ * It can be used for instance to save the current {@code Configuration} after
+ * it was modified. Some care has to be taken when changing the location of the
+ * {@code FileHandler}: The new location is recorded and also survives an
+ * invocation of the {@code resetResult()} method. However, when the builder's
+ * initialization parameters are reset by calling {@code resetParameters()} the
+ * location is reset, too.
+ * </p>
+ *
+ * @version $Id$
+ * @since 2.0
+ * @param <T> the concrete type of {@code Configuration} objects created by this
+ *        builder
+ */
+public class FileBasedConfigurationBuilder<T extends FileBasedConfiguration>
+        extends BasicConfigurationBuilder<T>
+{
+    /** Stores the FileHandler associated with the current configuration. */
+    private FileHandler currentFileHandler;
+
+    /** A flag whether the builder's parameters were reset. */
+    private boolean resetParameters;
+
+    /**
+     * Creates a new instance of {@code FileBasedConfigurationBuilder} which
+     * produces result objects of the specified class.
+     *
+     * @param resCls the result class (must not be <b>null</b>
+     * @throws IllegalArgumentException if the result class is <b>null</b>
+     */
+    public FileBasedConfigurationBuilder(Class<T> resCls)
+    {
+        super(resCls);
+    }
+
+    /**
+     * Creates a new instance of {@code FileBasedConfigurationBuilder} which
+     * produces result objects of the specified class and sets initialization
+     * parameters.
+     *
+     * @param resCls the result class (must not be <b>null</b>
+     * @param params a map with initialization parameters
+     * @throws IllegalArgumentException if the result class is <b>null</b>
+     */
+    public FileBasedConfigurationBuilder(Class<T> resCls,
+            Map<String, Object> params)
+    {
+        super(resCls, params);
+    }
+
+    /**
+     * Returns the {@code FileHandler} associated with this builder. If already
+     * a result object has been created, this {@code FileHandler} can be used to
+     * save it. Otherwise, the {@code FileHandler} from the initialization
+     * parameters is returned (which is not associated with a {@code FileBased}
+     * object). Result is never <b>null</b>.
+     *
+     * @return the {@code FileHandler} associated with this builder
+     */
+    public synchronized FileHandler getFileHandler()
+    {
+        return (currentFileHandler != null) ? currentFileHandler
+                : fetchFileHandlerFromParameters();
+    }
+
+    /**
+     * {@inheritDoc} This implementation just records the fact that new
+     * parameters have been set. This means that the next time a result object
+     * is created, the {@code FileHandler} has to be initialized from
+     * initialization parameters rather than reusing the existing one.
+     */
+    @Override
+    public synchronized BasicConfigurationBuilder<T> setParameters(
+            Map<String, Object> params)
+    {
+        super.setParameters(params);
+        resetParameters = true;
+        return this;
+    }
+
+    /**
+     * {@inheritDoc} This implementation deals with the creation and
+     * initialization of a {@code FileHandler} associated with the new result
+     * object.
+     */
+    @Override
+    protected void initResultInstance(T obj) throws ConfigurationException
+    {
+        FileHandler srcHandler =
+                (currentFileHandler != null && !resetParameters) ? currentFileHandler
+                        : fetchFileHandlerFromParameters();
+        currentFileHandler = new FileHandler(obj, srcHandler);
+        initFileHandler(currentFileHandler);
+        resetParameters = false;
+    }
+
+    /**
+     * Initializes the new current {@code FileHandler}. When a new result object
+     * is created, a new {@code FileHandler} is created, too, and associated
+     * with the result object. This new handler is passed to this method. If a
+     * location is defined, the result object is loaded from this location.
+     * Note: This method is called from a synchronized block.
+     *
+     * @param handler the new current {@code FileHandler}
+     * @throws ConfigurationException if an error occurs
+     */
+    protected void initFileHandler(FileHandler handler)
+            throws ConfigurationException
+    {
+        if (handler.isLocationDefined())
+        {
+            handler.load();
+        }
+    }
+
+    /**
+     * Obtains the {@code FileHandler} from this builder's parameters.
+     *
+     * @return the {@code FileHandler} from initialization parameters
+     */
+    private FileHandler fetchFileHandlerFromParameters()
+    {
+        return FileBasedBuilderParameters.fromParameters(getParameters(), true)
+                .getFileHandler();
+    }
+}

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Added: commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/builder/TestFileBasedConfigurationBuilder.java
URL: http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/builder/TestFileBasedConfigurationBuilder.java?rev=1396291&view=auto
==============================================================================
--- commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/builder/TestFileBasedConfigurationBuilder.java (added)
+++ commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/builder/TestFileBasedConfigurationBuilder.java Tue Oct  9 20:16:20 2012
@@ -0,0 +1,209 @@
+/*
+ * 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.commons.configuration.builder;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.commons.configuration.ConfigurationException;
+import org.apache.commons.configuration.PropertiesConfiguration;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+/**
+ * Test class for {@code FileBasedConfigurationBuilder}.
+ *
+ * @version $Id$
+ */
+public class TestFileBasedConfigurationBuilder
+{
+    /** Constant for a test property name. */
+    private static final String PROP = "testProperty";
+
+    /** Helper object for managing temporary files. */
+    @Rule
+    public TemporaryFolder folder = new TemporaryFolder();
+
+    /**
+     * Creates a test properties file with the given property value
+     *
+     * @param value the value for the test property
+     * @return the File object pointing to the test file
+     */
+    private File createTestFile(int value)
+    {
+        Writer out = null;
+        File file;
+        try
+        {
+            file = folder.newFile();
+            out = new FileWriter(file);
+            out.write(String.format("%s=%d", PROP, value));
+        }
+        catch (IOException ioex)
+        {
+            fail("Could not create test file: " + ioex);
+            return null; // cannot happen
+        }
+        finally
+        {
+            if (out != null)
+            {
+                try
+                {
+                    out.close();
+                }
+                catch (IOException ioex)
+                {
+                    // ignore
+                }
+            }
+        }
+        return file;
+    }
+
+    /**
+     * Tests whether a configuration can be created if no location is set.
+     */
+    @Test
+    public void testGetConfigurationNoLocation() throws ConfigurationException
+    {
+        Map<String, Object> params = new HashMap<String, Object>();
+        params.put("throwExceptionOnMissing", Boolean.TRUE);
+        FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
+                new FileBasedConfigurationBuilder<PropertiesConfiguration>(
+                        PropertiesConfiguration.class, params);
+        PropertiesConfiguration conf = builder.getConfiguration();
+        assertTrue("Property not set", conf.isThrowExceptionOnMissing());
+        assertTrue("Not empty", conf.isEmpty());
+    }
+
+    /**
+     * Tests whether a configuration is loaded from file if a location is
+     * provided.
+     */
+    @Test
+    public void testGetConfigurationLoadFromFile()
+            throws ConfigurationException
+    {
+        File file = createTestFile(1);
+        FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
+                new FileBasedConfigurationBuilder<PropertiesConfiguration>(
+                        PropertiesConfiguration.class);
+        builder.configure(new FileBasedBuilderParameters().setFile(file));
+        PropertiesConfiguration config = builder.getConfiguration();
+        assertEquals("Not read from file", 1, config.getInt(PROP));
+        assertSame("FileHandler not initialized", config, builder
+                .getFileHandler().getContent());
+    }
+
+    /**
+     * Tests that the location in the FileHandler remains the same if the
+     * builder's result is reset.
+     */
+    @Test
+    public void testLocationSurvivesResetResult() throws ConfigurationException
+    {
+        File file = createTestFile(1);
+        FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
+                new FileBasedConfigurationBuilder<PropertiesConfiguration>(
+                        PropertiesConfiguration.class);
+        builder.configure(new FileBasedBuilderParameters().setFile(file));
+        PropertiesConfiguration config = builder.getConfiguration();
+        builder.resetResult();
+        PropertiesConfiguration config2 = builder.getConfiguration();
+        assertNotSame("Same configuration", config, config2);
+        assertEquals("Not read from file", 1, config2.getInt(PROP));
+    }
+
+    /**
+     * Tests whether the location can be changed after a configuration has been
+     * created.
+     */
+    @Test
+    public void testChangeLocationAfterCreation() throws ConfigurationException
+    {
+        File file1 = createTestFile(1);
+        File file2 = createTestFile(2);
+        FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
+                new FileBasedConfigurationBuilder<PropertiesConfiguration>(
+                        PropertiesConfiguration.class);
+        builder.configure(new FileBasedBuilderParameters().setFile(file1));
+        builder.getConfiguration();
+        builder.getFileHandler().setFile(file2);
+        builder.resetResult();
+        PropertiesConfiguration config = builder.getConfiguration();
+        assertEquals("Not read from file 2", 2, config.getInt(PROP));
+    }
+
+    /**
+     * Tests whether a reset of the builder's initialization parameters also
+     * resets the file location.
+     */
+    @Test
+    public void testResetLocation() throws ConfigurationException
+    {
+        File file = createTestFile(1);
+        FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
+                new FileBasedConfigurationBuilder<PropertiesConfiguration>(
+                        PropertiesConfiguration.class);
+        builder.configure(new FileBasedBuilderParameters().setFile(file));
+        builder.getConfiguration();
+        builder.reset();
+        PropertiesConfiguration config = builder.getConfiguration();
+        assertTrue("Configuration was read from file", config.isEmpty());
+        assertFalse("FileHandler has location", builder.getFileHandler()
+                .isLocationDefined());
+    }
+
+    /**
+     * Tests whether it is possible to permanently change the location after a
+     * reset of parameters.
+     */
+    @Test
+    public void testChangeLocationAfterReset() throws ConfigurationException
+    {
+        File file1 = createTestFile(1);
+        File file2 = createTestFile(2);
+        FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
+                new FileBasedConfigurationBuilder<PropertiesConfiguration>(
+                        PropertiesConfiguration.class);
+        builder.configure(new FileBasedBuilderParameters().setFile(file1));
+        builder.getConfiguration();
+        builder.getFileHandler().setFile(file2);
+        builder.reset();
+        builder.configure(new FileBasedBuilderParameters().setFile(file1));
+        PropertiesConfiguration config = builder.getConfiguration();
+        assertEquals("Not read from file 1", 1, config.getInt(PROP));
+        builder.getFileHandler().setFile(file2);
+        builder.resetResult();
+        config = builder.getConfiguration();
+        assertEquals("Not read from file 2", 2, config.getInt(PROP));
+    }
+}

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