add convenient class for loading tab files

SVN: 1553

common/source/java/ch/systemsx/cisd/common/parser/IParserObjectFactoryFactory.java

+/*
+ * Copyright 2007 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.parser;
+
+
+/**
+ * A factory of {@link IParserObjectFactory} objects based on a {@link IPropertyMapper}.
+ *
+ * @author Franz-Josef Elmer
+ */
+public interface IParserObjectFactoryFactory<T>
+{
+    /**
+     * Creates a new factory for the specified property mapper.
+     */
+    public IParserObjectFactory<T> createFactory(IPropertyMapper propertyMapper);
+}

common/source/java/ch/systemsx/cisd/common/parser/TabFileLoader.java

+/*
+ * Copyright 2007 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.parser;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang.StringUtils;
+
+import ch.systemsx.cisd.common.exceptions.EnvironmentFailureException;
+import ch.systemsx.cisd.common.exceptions.UserFailureException;
+
+/**
+ * Convenient class to load a tab file and deliver a list of beans of type <code>T</code>.
+ *
+ * @author Franz-Josef Elmer
+ */
+public class TabFileLoader<T>
+{
+    
+    private final IParserObjectFactoryFactory<T> factory;
+
+    /**
+     * Creates a new instance based on the specified factory.
+     */
+    public TabFileLoader(IParserObjectFactoryFactory<T> factory)
+    {
+        assert factory != null : "Undefined factory";
+        this.factory = factory;
+    }
+
+    /**
+     * Loads from the specified tab file a list of objects of type <code>T</code>.
+     * 
+     * @throws UserFailureException if the file does not exists, the header line with correct column 
+     *      bean attribute names is missing, or a parsing error occurs.
+     * @throws EnvironmentFailureException if a IOException occured.
+     */
+    public List<T> load(File file)
+    {
+        // Just check whether the file exists. Lets <code>FileUtils</code> do the rest.
+        if (file.exists() == false)
+        {
+            throw new UserFailureException("Given file '" + file.getAbsolutePath() + "' does not exist.");
+        }
+        DefaultReaderParser<T> parser = new DefaultReaderParser<T>();
+        final ParserUtilities.Line headerLine =
+                ParserUtilities.getFirstAcceptedLine(file, ExcludeEmptyAndCommentLineFilter.INSTANCE);
+        if (headerLine == null)
+        {
+            throw new UserFailureException("No header line found in file '" + file.getAbsolutePath() + "'.");
+        }
+        final HeaderLineFilter lineFilter = new HeaderLineFilter(headerLine.number);
+        IPropertyMapper propertyMapper = new HeaderFilePropertyMapper(StringUtils.split(headerLine.text));
+        parser.setObjectFactory(factory.createFactory(propertyMapper));
+        FileReader reader = null;
+        try
+        {
+            reader = new FileReader(file);
+            return parser.parse(reader, lineFilter);
+        } catch (IOException ex)
+        {
+            throw new EnvironmentFailureException(ex.getMessage());
+        } catch (ParseException ex)
+        {
+            throw UserFailureException.fromTemplate("A problem has occurred while parsing line %d of file '%s' [%s].",
+                    ex.getLineNumber(), file, ex.getCause().getMessage());
+        } finally
+        {
+            IOUtils.closeQuietly(reader);
+        }
+
+    }
+}