org.openmrs.module.reporting.common.BeanPropertyComparator.java Source code

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Here is the source code for org.openmrs.module.reporting.common.BeanPropertyComparator.java

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/**
 * The contents of this file are subject to the OpenMRS Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://license.openmrs.org
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * Copyright (C) OpenMRS, LLC.  All Rights Reserved.
 */
package org.openmrs.module.reporting.common;

import java.util.Comparator;

import org.apache.commons.beanutils.PropertyUtils;

/**
 * A comparator that can compare 2 objects based on a particular nested property value
 */
@SuppressWarnings("rawtypes")
public class BeanPropertyComparator implements Comparator {

    private String sortSpecification;

    /**
     * Constructor
     */
    public BeanPropertyComparator(String sortSpecification) {
        this.sortSpecification = sortSpecification;
    }

    /**
     * @see Comparator#compare(Object, Object)
     */
    @SuppressWarnings({ "unchecked" })
    @Override
    public int compare(Object left, Object right) {
        try {
            for (String token : sortSpecification.split(",")) {
                String[] values = token.trim().split(" ");
                String property = values[0];
                boolean sortAsc = (values.length == 1 || !values[1].equalsIgnoreCase("desc"));

                Object valueLeft = PropertyUtils.getNestedProperty(left, property);
                Object valueRight = PropertyUtils.getNestedProperty(right, property);

                //We put NULLs at the bottom.
                if (valueLeft == null)
                    return 1;

                if (valueRight == null)
                    return -1;

                if (!valueLeft.equals(valueRight)) {
                    int ret = ((Comparable) valueLeft).compareTo(valueRight);
                    if (!sortAsc) {
                        ret = (ret == 1 ? -1 : 1);
                    }
                    return ret;
                }
                //else values are equal. Try next sort property
            }
        } catch (Exception ex) {
            throw new IllegalArgumentException("Unable to compare " + left + " and " + right
                    + " using sort specification: " + sortSpecification);
        }

        return 0;
    }
}