FileType.java

/**
 * FileType.java
 *
 * Created on 19.08.2009
 */

package treeProperties.types;


import treeProperties.PropertyType;
import treeProperties.TreeProperties;

import java.io.File;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


/**
 * The class FileType.
 *
 * @author Clemens Koza
 * @version V0.0 19.08.2009
 */
public class FileType implements PropertyType<File> {
    /** Constant <code>suffix="file"</code> */
    public static final String suffix = "file";
    /** Constant <code>type</code> */
    public static final Class<File> type = File.class;

    /**
     * <p>Getter for the field <code>suffix</code>.</p>
     *
     * @return a {@link java.lang.String} object.
     */
    public String getSuffix() {
        return suffix;
    }

    /**
     * <p>Getter for the field <code>type</code>.</p>
     *
     * @return a {@link java.lang.Class} object.
     */
    public Class<File> getType() {
        return type;
    }


    /** {@inheritDoc} */
    public File toObject(TreeProperties p, String s) {
        String path = getPath(s);
        File f = new File(path);
        if (f.isAbsolute()) return f;
        else return new File(p.getPath(), path);
    }

    /**
     * Returns a path path from a property value. Three substitutions are applied:
     * <ul>
     * <li>A "~/" or "~\" at the beginning is replaced with the user's home directory</li>
     * <li>A "$$" anywhere is replaced with a single "$"</li>
     * <li>A "${*}", where * is any string without "}", is replaced by {@link System#getProperty(String)}</li>
     * </ul>
     *
     * @param s a {@link java.lang.String} object.
     * @return a {@link java.lang.String} object.
     */
    public static String getPath(String s) {
        if (s.startsWith("~/")) s = System.getProperty("user.home") + "/" + s.substring(2);
        else if (s.startsWith("~\\")) s = System.getProperty("user.home") + "\\" + s.substring(2);
        Matcher m = Pattern.compile("\\$\\$|\\$\\{([^\\}]*)\\}").matcher(s);
        StringBuffer result = new StringBuffer();
        while (m.find()) {
            if (m.group().equals("$$")) m.appendReplacement(result, Matcher.quoteReplacement("$"));
            else m.appendReplacement(result, Matcher.quoteReplacement(System.getProperty(m.group(1))));
        }
        m.appendTail(result);
        return result.toString();
    }
}