/framework/src/play/utils/Utils.java

package play.utils;

import play.Play;
import play.mvc.Scope;

import java.lang.annotation.Annotation;
import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.CharsetDecoder;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Generic utils
 */
public class Utils {

    public static <T> String join(Iterable<T> values, String separator) {
        if (values == null) {
            return "";
        }
        Iterator<T> iter = values.iterator();
        if (!iter.hasNext()) {
            return "";
        }
        StringBuffer toReturn = new StringBuffer(String.valueOf(iter.next()));
        while (iter.hasNext()) {
            toReturn.append(separator + String.valueOf(iter.next()));
        }
        return toReturn.toString();
    }

    public static String join(String[] values, String separator) {
        return (values == null) ? "" : join(Arrays.asList(values), separator);
    }

    public static String join(Annotation[] values, String separator) {
        return (values == null) ? "" : join(Arrays.asList(values), separator);
    }

    public static String getSimpleNames(Annotation[] values) {
        if (values == null) {
            return "";
        }
        List<Annotation> a = Arrays.asList(values);
        Iterator<Annotation> iter = a.iterator();
        if (!iter.hasNext()) {
            return "";
        }
        StringBuffer toReturn = new StringBuffer("@" + iter.next().annotationType().getSimpleName());
        while (iter.hasNext()) {
            toReturn.append(", @" + iter.next().annotationType().getSimpleName());
        }
        return toReturn.toString();
    }

    /**
     * @deprecated Use Utils.join(values, " ");
     */
    @Deprecated
    public static String toString(Annotation[] values) {
        return join(values, " ");
    }

    public static String open(String file, Integer line) {
        if (Play.configuration.containsKey("play.editor")) {
            return String.format(Play.configuration.getProperty("play.editor"), Play.getFile(file).getAbsolutePath(), line);
        }
        return null;
    }

    /**
     * for java.util.Map
     */
    public static class Maps {

        public static void mergeValueInMap(Map<String, String[]> map, String name, String value) {
            String[] newValues = null;
            String[] oldValues = map.get(name);
            if (oldValues == null) {
                newValues = new String[1];
                newValues[0] = value;
            } else {
                newValues = new String[oldValues.length + 1];
                System.arraycopy(oldValues, 0, newValues, 0, oldValues.length);
                newValues[oldValues.length] = value;
            }
            map.put(name, newValues);
        }

        public static void mergeValueInMap(Map<String, String[]> map, String name, String[] values) {
            for (String value : values) {
                mergeValueInMap(map, name, value);
            }
        }

        public static <K, V> Map<K, V> filterMap(Map<K, V> map, String keypattern) {
            try {
                @SuppressWarnings("unchecked")
                Map<K, V> filtered = map.getClass().newInstance();
                for (Map.Entry<K, V> entry : map.entrySet()) {
                    K key = entry.getKey();
                    if (key.toString().matches(keypattern)) {
                        filtered.put(key, entry.getValue());
                    }
                }
                return filtered;
            } catch (Exception iex) {
                return null;
            }
        }
    }
    private static ThreadLocal<SimpleDateFormat> httpFormatter = new ThreadLocal<SimpleDateFormat>();

    public static SimpleDateFormat getHttpDateFormatter() {
        if (httpFormatter.get() == null) {
            httpFormatter.set(new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US));
            httpFormatter.get().setTimeZone(TimeZone.getTimeZone("GMT"));
        }
        return httpFormatter.get();
    }

    public static Map<String, String[]> filterMap(Map<String, String[]> map, String prefix) {
        Map<String, String[]> newMap = new HashMap<String, String[]>();
        for (String key : map.keySet()) {
            if (!key.startsWith(prefix + ".")) {
                newMap.put(key, map.get(key));
            }
        }
        return newMap;
    }

    public static Map<String, String> filterParams(Scope.Params params, String prefix) {
        return filterParams(params.all(), prefix);
    }

    public static Map<String, String> filterParams(Map<String, String[]> params, String prefix, String separator) {
        Map<String, String> filteredMap = new LinkedHashMap<String, String>();
        prefix += ".";
        for(Map.Entry<String, String[]> e: params.entrySet()){
            if(e.getKey().startsWith(prefix)) {
                filteredMap.put(
                        e.getKey().substring(prefix.length()),
                        Utils.join(e.getValue(), separator)
                );
            }
        }
        return filteredMap;
    }

    public static Map<String, String> filterParams(Map<String, String[]> params, String prefix) {
        return filterParams(params, prefix, ", ");
    }

    public static void kill(String pid) throws Exception {
        String os = System.getProperty("os.name");
        String command = (os.startsWith("Windows"))
                       ? "taskkill /F /PID " + pid
                       : "kill " + pid;
        Runtime.getRuntime().exec(command).waitFor();
    }

    public static class AlternativeDateFormat {

        Locale locale;
        List<SimpleDateFormat> formats = new ArrayList<SimpleDateFormat>();

        public AlternativeDateFormat(Locale locale, String... alternativeFormats) {
            super();
            this.locale = locale;
            setFormats(alternativeFormats);
        }

        public void setFormats(String... alternativeFormats) {
            for (String format : alternativeFormats) {
                formats.add(new SimpleDateFormat(format, locale));
            }
        }

        public Date parse(String source) throws ParseException {
            for (SimpleDateFormat dateFormat : formats) {
                if (source.length() == dateFormat.toPattern().replace("\'", "").length()) {
                    try {
                        return dateFormat.parse(source);
                    } catch (ParseException ex) {
                    }
                }
            }
            throw new ParseException("Date format not understood", 0);
        }
        static ThreadLocal<AlternativeDateFormat> dateformat = new ThreadLocal<AlternativeDateFormat>();

        public static AlternativeDateFormat getDefaultFormatter() {
            if (dateformat.get() == null) {
                dateformat.set(new AlternativeDateFormat(Locale.US,
                        "yyyy-MM-dd'T'HH:mm:ss'Z'", // ISO8601 + timezone
                        "yyyy-MM-dd'T'HH:mm:ss", // ISO8601
                        "yyyy-MM-dd HH:mm:ss",
                        "yyyyMMdd HHmmss",
                        "yyyy-MM-dd",
                        "yyyyMMdd'T'HHmmss",
                        "yyyyMMddHHmmss",
                        "dd'/'MM'/'yyyy",
                        "dd-MM-yyyy",
                        "dd'/'MM'/'yyyy HH:mm:ss",
                        "dd-MM-yyyy HH:mm:ss",
                        "ddMMyyyy HHmmss",
                "ddMMyyyy"));
            }
            return dateformat.get();
        }
    }

    private static final Pattern encodedChars = Pattern.compile("%([a-fA-F0-9][a-fA-F0-9])");

    public static String decodeBytes(String enc, CharsetDecoder decoder) {
        Matcher matcher = encodedChars.matcher(enc);
        StringBuffer buf = new StringBuffer();
        ByteBuffer bytes = ByteBuffer.allocate(enc.length() / 3);
        while (matcher.find()) {
            int b = Integer.parseInt(matcher.group(1), 16);
            bytes.put((byte) b);
        }
        bytes.flip();
        try {
            if (bytes.hasRemaining())
                return decoder.decode(bytes).toString();
            return enc;
        } catch (CharacterCodingException e) {
            throw new RuntimeException(e);
        }
    }
}