ProvenanceCountMap.java

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/*******************************************************************************
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use these files 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.
 *
 * Copyright 2014 - Juan Pino, Aurelien Waite, William Byrne
 *******************************************************************************/
package uk.ac.cam.eng.extraction.hadoop.datatypes;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import org.apache.commons.collections.map.LRUMap;
import org.apache.hadoop.io.ByteWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Writable;

public class ProvenanceCountMap implements Writable,
                Map<ByteWritable, IntWritable> {

        // Probably should fix the integer cache to work in the same way
        // as the cache in the Integer class
        private static LRUMap lruIntCache = new LRUMap(100000);

        private static Map<Byte, ByteWritable> bytesCache = new HashMap<>();

        private Map<ByteWritable, IntWritable> instance = new HashMap<ByteWritable, IntWritable>();

        public ProvenanceCountMap() {

        }

        public ProvenanceCountMap(ProvenanceCountMap other) {
                instance.putAll(other.instance);
        }

        public Map<ByteWritable, IntWritable> getInstance() {
                return instance;
        }

        private static ByteWritable getCached(byte b) {
                if (bytesCache.containsKey(b)) {
                        return bytesCache.get(b);
                }
                ByteWritable result = new ByteWritable(b);
                bytesCache.put(b, result);
                return result;
        }

        private static IntWritable getCached(int i) {
                if (lruIntCache.containsKey(i)) {
                        return (IntWritable) lruIntCache.get(i);
                }
                IntWritable result = new IntWritable(i);
                lruIntCache.put(i, result);
                return result;
        }


        public void increment(ProvenanceCountMap newCounts) {
                for (Entry<ByteWritable, IntWritable> provCount : newCounts.entrySet()) {
                        ByteWritable key = provCount.getKey();
                        if (containsKey(key)) {
                                put(key, getCached(get(key).get() + newCounts.get(key).get()));
                        } else {
                                put(key, newCounts.get(key));
                        }
                }
        }

        public int size() {
                return instance.size();
        }

        public boolean isEmpty() {
                return instance.isEmpty();
        }

        public boolean containsKey(Object key) {
                return instance.containsKey(key);
        }

        public boolean containsValue(Object value) {
                return instance.containsValue(value);
        }

        public IntWritable get(Object key) {
                return instance.get(key);
        }

        public IntWritable put(ByteWritable key, IntWritable value) {
                return instance.put(key, value);
        }

        public IntWritable remove(Object key) {
                return instance.remove(key);
        }

        public void putAll(Map<? extends ByteWritable, ? extends IntWritable> m) {
                instance.putAll(m);
        }

        public void clear() {
                instance.clear();
        }

        public Set<ByteWritable> keySet() {
                return instance.keySet();
        }

        public Collection<IntWritable> values() {
                return instance.values();
        }

        public Set<java.util.Map.Entry<ByteWritable, IntWritable>> entrySet() {
                return instance.entrySet();
        }

        public boolean equals(Object o) {
                return instance.equals(o);
        }

        public int hashCode() {
                return instance.hashCode();
        }

        public String toString() {
                return instance.toString();
        }

        @Override
        public void write(DataOutput out) throws IOException {
                out.writeByte(instance.size());
                for (Entry<ByteWritable, IntWritable> entry : instance.entrySet()) {
                        entry.getKey().write(out);
                        entry.getValue().write(out);
                }

        }

        @Override
        public void readFields(DataInput in) throws IOException {
                instance.clear();
                byte length = in.readByte();
                for (int i = 0; i < length; ++i) {
                        byte key = in.readByte();
                        int value = in.readInt();
                        instance.put(getCached(key), getCached(value));
                }

        }

}