tools.dynamia.commons.DynamicComparator Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of tools.dynamia.commons Show documentation
There is a newer version: 5.3.1
Show newest version
/*
 * Copyright (C) 2009 - 2019 Dynamia Soluciones IT S.A.S - NIT 900302344-1
 * Colombia - South America
 * All Rights Reserved.
 *
 * DynamiaTools is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License (LGPL v3) as
 * published by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * DynamiaTools is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with DynamiaTools.  If not, see .
 */
package tools.dynamia.commons;

import java.util.Comparator;

/**
 * Archivo: DynamicComparator.java Fecha Creacion: 4/05/2009
 *
 * @author Ing. Mario Serrano Leones
 * @param  the generic type
 */
public class DynamicComparator implements Comparator {

    /**
     * The field.
     */
    private String field;

    /**
     * The ascending.
     */
    private boolean ascending;

    /**
     * Instantiates a new dynamic comparator.
     */
    public DynamicComparator() {
        this(null);
    }

    /**
     * Instantiates a new dynamic comparator.
     *
     * @param field the field
     */
    public DynamicComparator(String field) {
        setField(field);
    }

    public DynamicComparator(String field, boolean ascending) {
        super();
        this.field = field;
        this.ascending = ascending;
    }

    /**
     * Checks if is ascending.
     *
     * @return true, if is ascending
     */
    public boolean isAscending() {
        return ascending;
    }

    /**
     * Sets the ascending.
     *
     * @param ascending the new ascending
     */
    public void setAscending(boolean ascending) {
        this.ascending = ascending;
    }

    /**
     * Gets the field.
     *
     * @return the field
     */
    public String getField() {
        return field;
    }

    /**
     * Sets the field.
     *
     * @param field the new field
     */
    public void setField(String field) {
        if (field != null && field.isEmpty()) {
            throw new IllegalArgumentException("Field name cannot be empty ");
        }

        this.field = field;
    }

    /*
	 * (non-Javadoc)
	 * 
	 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    @Override
    public int compare(T o1, T o2) {
        int result = 0;

        Comparable value1 = getValue(o1);
        Comparable value2 = getValue(o2);
        if (value1 != null && value2 == null) {
            result = 1;
        } else if (value1 == null && value2 != null) {
            result = -1;
        } else if (value1 == null && value2 == null) {
            result = 0;
        } else {
            result = value1.compareTo(value2);
        }

        if (!isAscending()) {
            if (result < 0) {
                result = 1;
            } else if (result > 0) {
                result = -1;
            }
        }

        return result;
    }

    /**
     * Gets the value.
     *
     * @param obj the obj
     * @return the value
     */
    @SuppressWarnings("rawtypes")
    private Comparable getValue(T obj) {
        Comparable value = null;
        if (obj != null && field != null) {

            try {
                Object result = BeanUtils.invokeGetMethod(obj, field);
                if (result instanceof Comparable) {
                    value = (Comparable) result;
                }
            } catch (Exception ex) {
                throw new RuntimeException(ex);
            }
        }
        return value;
    }
}