edu.illinois.cs.cogcomp.wikifier.utils.datastructure.StringMap.java Source code

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Here is the source code for edu.illinois.cs.cogcomp.wikifier.utils.datastructure.StringMap.java

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/**
 * This software is released under the University of Illinois/Research and Academic Use License. See
 * the LICENSE file in the root folder for details. Copyright (c) 2016
 *
 * Developed by: The Cognitive Computation Group University of Illinois at Urbana-Champaign
 * http://cogcomp.cs.illinois.edu/
 */
package edu.illinois.cs.cogcomp.wikifier.utils.datastructure;

import gnu.trove.map.hash.TCustomHashMap;
import gnu.trove.set.hash.TCustomHashSet;
import gnu.trove.strategy.HashingStrategy;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Collection;
import java.util.Map;
import java.util.Set;

import org.apache.commons.lang3.StringUtils;

import com.google.common.hash.HashFunction;
import com.google.common.hash.Hashing;

/**
 * A much more compact map than the default hash map
 * @author cheng88
 *
 * @param <T>
 */
public class StringMap<T> extends TCustomHashMap<String, T> implements Serializable {

    public static final float DEFAULT_LOAD_FACTOR = 0.6f;
    private static final HashFunction defaultHashFunction = Hashing.murmur3_32();
    private static final HashingStrategy<String> stringHashStrat = new HashingStrategy<String>() {

        /**
         *
         */
        private static final long serialVersionUID = -7000292520586925123L;

        @Override
        public int computeHashCode(String arg0) {
            return defaultHashFunction.hashString(arg0).asInt();
        }

        @Override
        public boolean equals(String arg0, String arg1) {
            return StringUtils.equals(arg0, arg1);
        }

    };

    public StringMap() {
        super(stringHashStrat, 10, DEFAULT_LOAD_FACTOR);
    }

    public StringMap(int capacity) {
        super(stringHashStrat, (int) Math.floor(capacity / DEFAULT_LOAD_FACTOR), DEFAULT_LOAD_FACTOR);
    }

    /**
     * Compacts itself upon finishing
     * @param map
     */
    public StringMap(Map<String, T> map) {
        super(stringHashStrat, map.size(), DEFAULT_LOAD_FACTOR);
        this.putAll(map);
        compact();
    }

    private void writeObject(ObjectOutputStream oos) throws IOException {
        compact();
        writeExternal(oos);
    }

    private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
        readExternal(ois);
    }

    /**
     * Better performance set
     * @author cheng88
     *
     */
    public static class StringSet extends TCustomHashSet<String> implements Set<String> {

        public StringSet(int capacity) {
            super(stringHashStrat, (int) Math.floor(capacity / DEFAULT_LOAD_FACTOR), DEFAULT_LOAD_FACTOR);
        }

        public StringSet(Collection<? extends String> coll) {
            super(stringHashStrat, coll);
        }

        public StringSet() {
            this(10);
        }
    }

}