bitsetconverter.java

xstream是一个把java object序列化成xml文件的开源库,轻便好用

package com.thoughtworks.xstream.converters.collections;

import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;

import java.util.BitSet;
import java.util.StringTokenizer;

/**
 * Converts a java.util.BitSet to XML, as a compact
 * comma delimited list of ones and zeros.
 *
 * @author Joe Walnes
 */
public class BitSetConverter implements Converter {

    public boolean canConvert(Class type) {
        return type.equals(BitSet.class);
    }

    public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) {
        BitSet bitSet = (BitSet) source;
        StringBuffer buffer = new StringBuffer();
        boolean seenFirst = false;
        for (int i = 0; i < bitSet.length(); i++) {
            if (bitSet.get(i)) {
                if (seenFirst) {
                    buffer.append(',');
                } else {
                    seenFirst = true;
                }
                buffer.append(i);
            }
        }
        writer.setValue(buffer.toString());
    }

    public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
        BitSet result = new BitSet();
        StringTokenizer tokenizer = new StringTokenizer(reader.getValue(), ",", false);
        while (tokenizer.hasMoreTokens()) {
            int index = Integer.parseInt(tokenizer.nextToken());
            result.set(index);
        }
        return result;
    }
}