CategoricalAttribute.java

/*
 * $#
 * FOS API
 *  
 * Copyright (C) 2013 Feedzai SA
 *  
 * This software is licensed under the Apache License, Version 2.0 (the "Apache License") or the GNU
 * Lesser General Public License version 3 (the "GPL License"). You may choose either license to govern
 * your use of this software only upon the condition that you accept all of the terms of either the Apache
 * License or the LGPL License.
 * 
 * You may obtain a copy of the Apache License and the LGPL License at:
 * 
 * http://www.apache.org/licenses/LICENSE-2.0.txt
 * http://www.gnu.org/licenses/lgpl-3.0.txt
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the Apache License
 * or the LGPL License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the Apache License and the LGPL License for the specific language governing
 * permissions and limitations under the Apache License and the LGPL License.
 * #$
 */
package com.feedzai.fos.api;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.feedzai.fos.common.validation.NotBlank;
import com.google.common.base.Joiner;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableList;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static com.google.common.base.Objects.toStringHelper;
import static com.google.common.base.Preconditions.checkArgument;


/**
 * A CategoricalAttribute will be mapped into the underlying implementation categorical type.
 * It holds a list of all possible categorical values and the ability to replace a unknown categorical value
 * by a default value.
 */
public final class CategoricalAttribute extends Attribute {
    private List<String> categoricalInstances;

    /**
     * Creates a new categorical with the given <code>name</code>, <code>type</code> and <code>categoricalInstances</code>.
     * <p/> The <code>categoricalInstances</code> is the set of possible values that the field can take.
     *
     * @param name                  the name of the field
     * @param pcategoricalInstances for <code>type=nominal</code>, defines the possibles values of the field
     */
    @JsonCreator
    public CategoricalAttribute(@NotBlank @JsonProperty("name") String name,
                                @JsonProperty("categoricalInstances") List<String> pcategoricalInstances) {
        super(name);

        checkArgument(pcategoricalInstances != null && pcategoricalInstances.size() > 0, "Missing instances for nominal value");
        checkArgument(!pcategoricalInstances.contains(""), "Nominal instances values must not empty");
        checkArgument(!pcategoricalInstances.contains(null), "Nominal instances must not be null");

        String[] sorted = pcategoricalInstances.toArray(new String[pcategoricalInstances.size()]);
        Arrays.sort(sorted);

        this.categoricalInstances = ImmutableList.copyOf(sorted);
    }

    /**
     * Gets the list of nominal values for this field (if the <code>type=Nominal</code>) or null otherwise.
     *
     * @return a list of nominal values (can be null!!)
     */
    public List<String> getCategoricalInstances() {
        return ImmutableList.copyOf(categoricalInstances);
    }

    @Override
    protected double parse(Object original) throws FOSException {
        String value = original.toString();
        int index = Collections.binarySearch(categoricalInstances, value);

        if (index < 0) {
            throw new FOSException(String.format("Failed to parse %s", original));
        }

        return index;
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(categoricalInstances);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || getClass() != obj.getClass()) {
            return false;
        }
        if (!super.equals(obj)) {
            return false;
        }
        final CategoricalAttribute other = (CategoricalAttribute) obj;
        return Objects.equal(categoricalInstances, other.categoricalInstances);
    }

    @Override
    public String toString() {
        return toStringHelper(this)
                .addValue(getName())
                .add("categoricalInstances", categoricalInstances)
                .toString();
    }
}