exm.stc.common.util.Misc.java Source code

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Here is the source code for exm.stc.common.util.Misc.java

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/*
 * Copyright 2013 University of Chicago and Argonne National Laboratory
 *
 * 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 exm.stc.common.util;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import com.google.common.collect.Multimap;

import exm.stc.common.exceptions.STCRuntimeError;
import exm.stc.common.lang.Types.Type;

/**
 * Miscellaneous utility functions
 * @author wozniak
 * */
public class Misc {
    static DateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");

    /**
       @return Current time formatted as human-readable String
     */
    public static String timestamp() {
        return df.format(new Date());
    }

    public static String stackTrace(Throwable e) {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        e.printStackTrace(pw);
        return sw.toString();
    }

    /**
     * Invert mapping, assuming surjective (i.e. each key maps to unique value)
     * @param m
     * @return
     */
    public static <K, V> Map<V, K> invertSurjective(Map<K, V> m) {
        Map<V, K> result = new HashMap<V, K>();
        for (Map.Entry<K, V> e : m.entrySet()) {
            K k = e.getKey();
            V v = e.getValue();
            K prev = result.put(v, k);
            if (prev != null) {
                throw new STCRuntimeError("Duplicate value when inverting: " + v + " for keys " + prev + ", " + k);
            }
        }

        return result;
    }

    public static void putAllMultimap(Multimap<String, Type> dst, Map<String, Type> src) {
        for (Entry<String, Type> e : src.entrySet()) {
            dst.put(e.getKey(), e.getValue());
        }
    }
}