org.databene.formats.properties.BeanPropertiesFileWriter Maven / Gradle / Ivy

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'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.
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/*
 * 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.properties;

import org.databene.commons.Context;
import org.databene.commons.ConversionException;
import org.databene.commons.Converter;
import org.databene.commons.StringUtil;
import org.databene.commons.SystemInfo;
import org.databene.commons.BeanUtil;
import org.databene.commons.bean.BeanToPropertyArrayConverter;
import org.databene.commons.converter.ArrayConverter;
import org.databene.commons.converter.ConverterChain;
import org.databene.commons.converter.ToStringConverter;
import org.databene.formats.script.AbstractScript;
import org.databene.formats.script.Script;
import org.databene.formats.script.ScriptException;
import org.databene.formats.script.ScriptUtil;
import org.databene.formats.script.ScriptedDocumentWriter;

import java.io.IOException;
import java.io.Writer;
import java.io.FileWriter;
import java.text.MessageFormat;
import java.text.FieldPosition;
import java.beans.PropertyDescriptor;

/**
 * Writes JavaBeans to property files.

 * 

 * Created: 07.06.2007 13:05:38
 * @author Volker Bergmann
 */
public class BeanPropertiesFileWriter extends ScriptedDocumentWriter {

    public BeanPropertiesFileWriter(Writer out, String ... propertyNames) {
        this(out, null, (Script)null, (Script)null, propertyNames);
    }

    public BeanPropertiesFileWriter(Writer out, String prefixPattern, String headerScriptUrl, String footerScriptUrl,
                                    String ... propertyNames)
            throws IOException {
        this(
            out,
            prefixPattern,
            (headerScriptUrl != null ? ScriptUtil.readFile(headerScriptUrl) : null),
            (footerScriptUrl != null ? ScriptUtil.readFile(footerScriptUrl) : null),
            propertyNames
        );
    }

    public BeanPropertiesFileWriter(Writer out, String prefixPattern, Script headerScript, Script footerScript,
                                    String ... propertyNames) {
        super( out, headerScript, new PartScript(prefixPattern, propertyNames), footerScript);
    }

    public static  void persist(T bean, String filename) throws IOException {
        FileWriter out = new FileWriter(filename);
        BeanPropertiesFileWriter writer = new BeanPropertiesFileWriter(out, getPropertyNames(bean.getClass()));
        writer.writeHeader();
        writer.writeElement(bean);
        writer.close();
        out.close();
    }

    private static String[] getPropertyNames(Class beanType) {
        PropertyDescriptor[] descriptors = BeanUtil.getPropertyDescriptors(beanType);
        String[] names = new String[descriptors.length];
        for (int i = 0; i < descriptors.length; i++)
            names[i] = descriptors[i].getName();
        return names;
    }

    // scripts ---------------------------------------------------------------------------------------------------------

    private static class PartScript extends AbstractScript {

        private static final String LINE_SEPARATOR = SystemInfo.getLineSeparator();

        private MessageFormat prefixFormat;
        private String[] propertyNames;
        private Converter converter;

        private int elementCount;
        private StringBuffer buffer;
        FieldPosition pos0 = new FieldPosition(0);

        @SuppressWarnings({ "unchecked", "rawtypes" })
        public PartScript(String prefixPattern, String ... propertyNames) {
            this.prefixFormat = (prefixPattern != null ? new MessageFormat(prefixPattern) : null);
            this.propertyNames = propertyNames;
            int length = propertyNames.length;
            Converter[] propertyConverters = new Converter[length];
            for (int i = 0; i < length; i++)
                propertyConverters[i] = new ToStringConverter();
            this.converter = new ConverterChain(
                new BeanToPropertyArrayConverter(propertyNames),
                new ArrayConverter(Object.class, String.class, propertyConverters)
            );
            this.elementCount = 0;
            this.buffer = new StringBuffer();
        }

        @Override
        public void execute(Context context, Writer out) throws IOException, ScriptException {
            try {
                elementCount++;
                String[] cells = converter.convert(context.get("part"));
                String prefix = "";
                if (prefixFormat != null) {
                    prefixFormat.format(new Integer[] {elementCount}, buffer, pos0);
                    prefix = buffer.toString();
                    buffer.delete(0, buffer.length());
                }
                for (int i = 0; i < cells.length; i++) {
                    out.write(prefix);
                    out.write(propertyNames[i]);
                    out.write('=');
                    out.write(StringUtil.escape(cells[i]));
                    out.write(LINE_SEPARATOR);
                }
            } catch (ConversionException e) {
                throw new ScriptException(e);
            }
        }

    }
}