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/*
 * Copyright (C) 2004-2014 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.commons;

import java.io.IOException;
import java.lang.reflect.Array;
import java.text.FieldPosition;
import java.text.Format;
import java.text.ParsePosition;

import org.databene.commons.converter.AnyConverter;
import org.databene.commons.converter.ToStringConverter;

/**
 * java.lang.text.Format implementation for formatting and parsing arrays.
 * Created: 20.06.2007 07:04:37
 * @author Volker Bergmann
 */
public class ArrayFormat extends Format {

    // defaults --------------------------------------------------------------------------------------------------------

    private static final long serialVersionUID = 290320869220307493L;
    
	private static final String DEFAULT_SEPARATOR = ", ";
    private static final Converter DEFAULT_ITEM_FORMATTER = new ToStringConverter("null");

    // attributes ------------------------------------------------------------------------------------------------------

    private Converter itemFormatter;
    private String separator;

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

    public ArrayFormat() {
        this(DEFAULT_ITEM_FORMATTER, DEFAULT_SEPARATOR);
    }

    public ArrayFormat(String separator) {
        this(DEFAULT_ITEM_FORMATTER, separator);
    }

    public ArrayFormat(Converter itemFormat) {
        this(itemFormat, DEFAULT_SEPARATOR);
    }

    public ArrayFormat(Converter itemFormatter, String separator) {
        this.itemFormatter = itemFormatter;
        this.separator = separator;
    }

    // java.text.Format interface implementation -----------------------------------------------------------------------

    @Override
    public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
        return formatPart(toAppendTo, itemFormatter, separator, 0, Array.getLength(obj), obj);
    }

    @Override
    public Object parseObject(String source, ParsePosition pos) {
        String[] result = parse(source, separator, String.class);
        pos.setIndex(source.length());
		return result;
    }

    // publicly available utility methods ------------------------------------------------------------------------------

    public static  String format(T ... items) {
        return format(", ", items);
    }

    public static  String format(String separator, T ... items) {
        if (items == null)
            return "";
        return formatPart(null, separator, 0, items.length, items);
    }

    public static  String format(Converter formatter, String separator, T ... items) {
        return formatPart(formatter, separator, 0, items.length, items);
    }

    public static  String formatPart(int offset, int length, T ... items) {
        return formatPart(null, DEFAULT_SEPARATOR, offset, length, items);
    }

    public static  String formatPart(String separator, int offset, int length, T ... items) {
        return formatPart(null, separator, offset, length, items);
    }

    public static  String formatPart(Converter formatter, String separator, int offset, int length, T ... items) {
        if (items.length == 0)
            return "";
        return formatPart(new StringBuilder(), formatter, separator, offset, length, items).toString();
    }

    public static  E formatPart(E toAppendTo, Converter formatter, String separator,
                                                         int offset, int length, Object items) {
        if (Array.getLength(items) == 0)
            return toAppendTo;
        try {
            if (formatter == null)
                formatter = DEFAULT_ITEM_FORMATTER;
            toAppendTo.append(formatter.convert(Array.get(items, offset)));
            for (int i = 1; i < length; i++)
                toAppendTo.append(separator).append(formatter.convert(Array.get(items, offset + i)));
            return toAppendTo;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static String formatInts(String separator, int ... items) {
        if (items.length == 0)
            return "";
        StringBuilder builder = new StringBuilder();
        builder.append(items[0]);
        for (int i = 1; i < items.length; i++)
            builder.append(separator).append(items[i]);
        return builder.toString();
    }

    public static String formatBytes(String separator, byte ... items) {
        if (items.length == 0)
            return "";
        StringBuilder builder = new StringBuilder();
        builder.append(items[0]);
        for (int i = 1; i < items.length; i++)
            builder.append(separator).append(items[i]);
        return builder.toString();
    }

    public static String formatChars(String separator, char ... items) {
        if (items.length == 0)
            return "";
        StringBuilder builder = new StringBuilder();
        builder.append(items[0]);
        for (int i = 1; i < items.length; i++)
            builder.append(separator).append(items[i]);
        return builder.toString();
    }

    public static String formatStrings(String separator, String ... items) {
        if (items == null)
            return "";
        return formatPart(null, separator, 0, items.length, items);
    }
    
    // parse methods ---------------------------------------------------------------------------------------------------

    public static  T[] parse(String source, String separator, Class componentType) {
        ArrayBuilder builder = new ArrayBuilder(componentType);
        int i = 0;
        int sepIndex;
        while ((sepIndex = source.indexOf(separator, i)) >= 0) {
            String token = source.substring(i, sepIndex);
            builder.add(AnyConverter.convert(token, componentType));
            i = sepIndex + separator.length();
        }
        builder.add(AnyConverter.convert(source.substring(i, source.length()), componentType));
        return builder.toArray();
    }

}