com.davidbracewell.math.linear.VectorMap.java Source code

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Here is the source code for com.davidbracewell.math.linear.VectorMap.java

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/*
 * (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.math.linear;

import com.davidbracewell.math.DoubleEntry;
import com.davidbracewell.tuple.Pair;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterators;
import com.google.common.primitives.Doubles;

import javax.annotation.Nullable;
import java.util.*;

/**
 * The type Vector map.
 *
 * @author David B. Bracewell
 */
public class VectorMap extends AbstractMap<Integer, Double> {

    private final Vector vector;
    private final Predicate<Double> isValidValue;

    /**
     * Instantiates a new Vector map.
     *
     * @param vector     the vector
     * @param validValue the valid value
     */
    protected VectorMap(Vector vector, Predicate<Double> validValue) {
        this.vector = vector;
        isValidValue = validValue;
    }

    /**
     * Wrap map.
     *
     * @param v          the v
     * @param validValue the valid value
     * @return the map
     */
    public static Map<Integer, Double> wrap(Vector v, Predicate<Double> validValue) {
        return new VectorMap(Preconditions.checkNotNull(v), validValue);
    }

    /**
     * Wrap map.
     *
     * @param v the v
     * @return the map
     */
    public static Map<Integer, Double> wrap(Vector v) {
        return new VectorMap(Preconditions.checkNotNull(v), VALID_VALUES.NON_ZERO);
    }

    @Override
    public int size() {
        return vector.dimension();
    }

    @Override
    public boolean containsKey(Object key) {
        return key instanceof Number && isValidValue.apply(vector.get(((Number) key).intValue()));
    }

    @Override
    public Double get(Object key) {
        if (key instanceof Number) {
            return vector.get(((Number) key).intValue());
        }
        return 0d;
    }

    @Override
    public Set<Integer> keySet() {
        return new AbstractSet<Integer>() {

            @Override
            public Iterator<Integer> iterator() {
                return Iterators.transform(vector.nonZeroIterator(), new Function<DoubleEntry, Integer>() {
                    @Nullable
                    @Override
                    public Integer apply(@Nullable DoubleEntry input) {
                        return input == null ? null : input.index;
                    }
                });
            }

            @Override
            public int size() {
                return vector.size();
            }

        };
    }

    @Override
    public Set<Entry<Integer, Double>> entrySet() {
        return new AbstractSet<Entry<Integer, Double>>() {
            @Override
            public Iterator<Entry<Integer, Double>> iterator() {
                return Iterators.transform(vector.iterator(), new Function<DoubleEntry, Entry<Integer, Double>>() {
                    @Nullable
                    @Override
                    public Entry<Integer, Double> apply(@Nullable DoubleEntry input) {
                        return input == null ? null : Pair.of(input.index, input.value);
                    }
                });
            }

            @Override
            public int size() {
                return vector.dimension();
            }
        };
    }

    public static enum VALID_VALUES implements Predicate<Double> {
        /**
         * The NON_ZERO.
         */
        NON_ZERO {
            @Override
            public boolean apply(@Nullable Double input) {
                return input != null && input != 0;
            }
        },
        /**
         * The FINITE.
         */
        FINITE {
            @Override
            public boolean apply(@Nullable Double input) {
                return input != null && Doubles.isFinite(input);
            }
        }
    }

}//END OF VectorMap