bundleplugin/src/main/java/aQute/lib/data/Data.java

package aQute.lib.data;

import java.lang.reflect.*;
import java.util.*;
import java.util.regex.*;

public class Data {

	public static String validate(Object o) throws Exception {
		StringBuilder sb = new StringBuilder();
		Formatter formatter = new Formatter(sb);

		Field fields[] = o.getClass().getFields();
		for (Field f : fields) {
			Validator patternValidator = f.getAnnotation(Validator.class);
			Numeric numericValidator = f.getAnnotation(Numeric.class);
			AllowNull allowNull = f.getAnnotation(AllowNull.class);
			Object value = f.get(o);
			if (value == null) {
				if (allowNull == null)
					formatter.format("Value for %s must not be null\n", f.getName());
			} else {

				if (patternValidator != null) {
					Pattern p = Pattern.compile(patternValidator.value());
					Matcher m = p.matcher(value.toString());
					if (!m.matches()) {
						String reason = patternValidator.reason();
						if (reason.length() == 0)
							formatter.format("Value for %s=%s does not match pattern %s\n", f.getName(), value,
									patternValidator.value());
						else
							formatter.format("Value for %s=%s %s\n", f.getName(), value, reason);
					}
				}

				if (numericValidator != null) {
					if (o instanceof String) {
						try {
							o = Double.parseDouble((String) o);
						}
						catch (Exception e) {
							formatter.format("Value for %s=%s %s\n", f.getName(), value, "Not a number");
						}
					}

					try {
						Number n = (Number) o;
						long number = n.longValue();
						if (number >= numericValidator.min() && number < numericValidator.max()) {
							formatter.format("Value for %s=%s not in valid range (%s,%s]\n", f.getName(), value,
									numericValidator.min(), numericValidator.max());
						}
					}
					catch (ClassCastException e) {
						formatter.format("Value for %s=%s [%s,%s) is not a number\n", f.getName(), value,
								numericValidator.min(), numericValidator.max());
					}
				}
			}
		}
		if (sb.length() == 0)
			return null;

		if (sb.length() > 0)
			sb.delete(sb.length() - 1, sb.length());
		return sb.toString();
	}

	public static void details(Object data, Appendable out) throws Exception {
		Field fields[] = data.getClass().getFields();
		Formatter formatter = new Formatter(out);

		for (Field f : fields) {
			String name = f.getName();
			name = Character.toUpperCase(name.charAt(0)) + name.substring(1);
			formatter.format("%-40s %s\n", name, f.get(data));
		}
	}
}