org.databene.formats.csv.CSVToJavaBeanMapper Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of databene-formats Show documentation
'Databene Formats' is an open source software library for supporting data file and other formats like CSV, fixed width files, XLS, Properties and Regex. It is designed for multithreaded use and high performance.
There is a newer version: 1.0.14
Show newest version
/*
 * Copyright (C) 2011-2014 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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.databene.formats.csv;

import org.databene.commons.BeanUtil;
import org.databene.commons.ConfigurationError;
import org.databene.commons.IOUtil;
import org.databene.commons.mutator.AnyMutator;
import org.databene.commons.mutator.NamedMutator;
import org.databene.formats.DataContainer;
import org.databene.formats.DataIterator;
import org.databene.formats.util.ThreadLocalDataContainer;

import java.io.*;

/**
 * Reads a CSV file and maps its columns to JavaBeans.

 * 

 * Created: 21.07.2006 15:07:36
 * @author Volker Bergmann
 */
public class CSVToJavaBeanMapper implements DataIterator {

    private CSVLineIterator iterator;
    private Class type;
    private String emptyValue;
    
    private NamedMutator[] mutators;
    private int classIndex;
    private ThreadLocalDataContainer dataContainer = new ThreadLocalDataContainer();


    // constructors ----------------------------------------------------------------------------------------------------

    public CSVToJavaBeanMapper(Reader reader, Class type) throws IOException {
        this(reader, type, ',', null);
    }

    public CSVToJavaBeanMapper(Reader reader, Class type, char separator, String emptyValue) throws IOException {
    	CSVLineIterator iterator = new CSVLineIterator(reader, separator, true);
        String[] attributeNames = iterator.next(dataContainer.get()).getData();
        init(iterator, type, emptyValue, attributeNames);
    }

    public CSVToJavaBeanMapper(Reader reader, Class type, char separator, String emptyValue, String[] attributeNames) throws IOException {
    	CSVLineIterator iterator = new CSVLineIterator(reader, separator, true);
        init(iterator, type, emptyValue, attributeNames);
    }


    // DataIterator interface implementation ---------------------------------------------------------------------------

    @Override
	public Class getType() {
    	return type;
    }
    
	@SuppressWarnings("unchecked")
	@Override
	public DataContainer next(DataContainer wrapper) {
        int i = 0;
        String value = null;
        try {
            DataContainer tmp = nextRaw(dataContainer.get());
            if (tmp == null)
            	return null;
			String[] line = tmp.getData();
			if (line.length == 0)
				return null;
			Class beanClass = (classIndex >= 0 ? (Class) BeanUtil.forName(line[classIndex]) : type);
            E bean = BeanUtil.newInstance(beanClass);
            int columns = Math.min(line.length, mutators.length);
            for (i = 0; i < columns; i++) {
            	if (i != classIndex) {
	                value = line[i];
	                if (value != null && value.length() == 0)
	                    value = emptyValue;
	                mutators[i].setValue(bean, value);
            	}
            }
            return wrapper.setData(bean);
        } catch (Exception e) {
            throw new ConfigurationError("Failed to set property '" + 
                    mutators[i].getName() + "' to '" + value + "' on class " + type, e);
        }
    }

    public DataContainer nextRaw(DataContainer wrapper) {
    	return iterator.next(wrapper);
    }

    @Override
	public void close() {
    	IOUtil.close(iterator);
    }


    // further public methods ------------------------------------------------------------------------------------------

    public void skip() {
    	iterator.next(dataContainer.get());
    }


    // private helpers -------------------------------------------------------------------------------------------------

    private void init(CSVLineIterator iterator, Class type, String emptyValue, String[] attributeNames) {
		this.iterator = iterator;
        this.type = type;
        this.emptyValue = emptyValue;
        this.mutators = new NamedMutator[attributeNames.length];
        this.classIndex = -1;
        for (int i = 0; i < attributeNames.length; i++) {
            String attributeName = attributeNames[i];
            if ("class".equals(attributeName)) {
            	mutators[i] = null;
            	this.classIndex = i;
            } else {
            	mutators[i] = new AnyMutator(attributeName, false, true);
            }
        }
	}

}