com.davidbracewell.collection.Counters Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of mango Show documentation
A set of utilities and tools to speed up and ease programming in Java.
There is a newer version: 0.5
/*
 * (c) 2005 David B. Bracewell
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.davidbracewell.collection;

import com.davidbracewell.conversion.Convert;
import com.davidbracewell.io.CSV;
import com.davidbracewell.io.resource.Resource;
import com.davidbracewell.io.structured.csv.CSVReader;
import lombok.NonNull;

import java.io.IOException;
import java.util.Arrays;
import java.util.EnumSet;
import java.util.Map;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Collector;

/**
 * The interface Counters.
 */
public interface Counters {

  /**
   * From array counter.
   *
   * @param array the array
   * @return the counter
   */
  static Counter fromArray(@NonNull double[] array) {
    Counter counter = Counters.newHashMapCounter();
    for (int i = 0; i < array.length; i++) {
      counter.set(i, array[i]);
    }
    return counter;
  }

  /**
   * New concurrent counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  @SafeVarargs
  static  Counter newConcurrentCounter(TYPE... items) {
    if (items == null) {
      return new ConcurrentMapCounter<>();
    }
    return newConcurrentCounter(Arrays.asList(items));
  }

  /**
   * New concurrent counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  static  Counter newConcurrentCounter(@NonNull Iterable items) {
    return new ConcurrentMapCounter<>(items);
  }

  /**
   * New concurrent counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  static  Counter newConcurrentCounter(@NonNull Map items) {
    return new ConcurrentMapCounter<>(items);
  }

  /**
   * New concurrent counter.
   *
   * @param   the type parameter
   * @param counter the counter
   * @return the counter
   */
  static  Counter newConcurrentCounter(@NonNull Counter counter) {
    return new ConcurrentMapCounter<>(counter);
  }

  /**
   * New hash map counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  @SafeVarargs
  static  Counter newHashMapCounter(TYPE... items) {
    if (items == null) {
      return new HashMapCounter<>();
    }
    return newHashMapCounter(Arrays.asList(items));
  }

  /**
   * New hash map counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  static  Counter newHashMapCounter(@NonNull Iterable items) {
    return new HashMapCounter<>(items);
  }

  /**
   * New hash map counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  static  Counter newHashMapCounter(@NonNull Map items) {
    return new HashMapCounter<>(items);
  }

  /**
   * New hash map counter.
   *
   * @param   the type parameter
   * @param counter the counter
   * @return the counter
   */
  static  Counter newHashMapCounter(@NonNull Counter counter) {
    return new HashMapCounter<>(counter);
  }

  /**
   * New tree map counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  @SafeVarargs
  static  Counter newTreeMapCounter(TYPE... items) {
    if (items == null) {
      return new TreeMapCounter<>();
    }
    return newTreeMapCounter(Arrays.asList(items));
  }

  /**
   * New tree map counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  static  Counter newTreeMapCounter(@NonNull Iterable items) {
    return new TreeMapCounter<>(items);
  }

  /**
   * New tree map counter.
   *
   * @param  the type parameter
   * @param items  the items
   * @return the counter
   */
  static  Counter newTreeMapCounter(@NonNull Map items) {
    return new TreeMapCounter<>(items);
  }

  /**
   * New tree map counter.
   *
   * @param   the type parameter
   * @param counter the counter
   * @return the counter
   */
  static  Counter newTreeMapCounter(@NonNull Counter counter) {
    return new TreeMapCounter<>(counter);
  }

  /**
   * Unmodifable counter.
   *
   * @param   the type parameter
   * @param counter the counter
   * @return the counter
   */
  static  Counter unmodifableCounter(@NonNull final Counter counter) {
    return new UnmodifiableCounter<>(counter);
  }

  /**
   * From csv counter.
   *
   * @param    the type parameter
   * @param resource the resource
   * @param keyClass the key class
   * @param supplier the supplier
   * @return the counter
   * @throws IOException the io exception
   */
  static  Counter fromCSV(@NonNull Resource resource, @NonNull Class keyClass, @NonNull Supplier> supplier) throws IOException {
    Counter counter = supplier.get();
    try (CSVReader reader = CSV.builder().reader(resource)) {
      reader.forEach(row -> {
        if (row.size() >= 2) {
          counter.increment(Convert.convert(row.get(0), keyClass), Double.parseDouble(row.get(1)));
        }
      });
    }
    return counter;
  }

  /**
   * Collector collector.
   *
   * @param  the type parameter
   * @return the collector
   */
  static  Collector, Counter> collector() {
    return new CounterCollector<>();
  }

  /**
   * The type Counter collector.
   *
   * @param  the type parameter
   */
  class CounterCollector implements Collector, Counter> {

    @Override
    public Supplier> supplier() {
      return Counters::newHashMapCounter;
    }

    @Override
    public BiConsumer, T> accumulator() {
      return Counter::increment;
    }

    @Override
    public BinaryOperator> combiner() {
      return (c1, c2) -> {
        c1.merge(c2);
        return c1;
      };
    }

    @Override
    public Function, Counter> finisher() {
      return c -> c;
    }

    @Override
    public Set characteristics() {
      return EnumSet.of(Characteristics.UNORDERED);
    }

  }


}//END OF Counters