com.hula.lang.commands.data.Sort.java Source code

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Here is the source code for com.hula.lang.commands.data.Sort.java

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/**
 * Copyright 2013 Simon Curd <simoncurd@gmail.com>
 * 
 * Licensed 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.hula.lang.commands.data;

import java.math.BigDecimal;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.apache.commons.beanutils.PropertyUtils;

import com.hula.lang.commands.AbstractCommand;
import com.hula.lang.model.NoReturnParam;
import com.hula.lang.model.RequiresParams;
import com.hula.lang.parser.exception.ParseError;
import com.hula.lang.parser.util.ValidationUtil;
import com.hula.lang.runtime.RuntimeConnector;
import com.hula.lang.runtime.exception.HulaRuntimeException;

/**
 * The Sort command sorts a list of objects. <br/>
 * <br/>
 * 
 * Example Usage:<br/>
 * <br/>
 * 
 * Sort a list of names in ascending order. <br/>
 * <code>Sort $namelist, type=Alpha</code><br/>
 * <br/>
 * 
 * Sort a list of names in descending order. <br/>
 * <code>Sort $namelist, type=Alpha, order=desc</code><br/>
 * <br/>
 * 
 * Sort a list of person objects on the name attribute.<br/>
 * <code>Sort $personlist, type=Alpha, property=name</code><br/>
 * <br/>
 * 
 * Sort a list of person objects on the age attribute.<br/>
 * <code>Sort $personlist, type=Numeric, property=age</code><br/>
 * <br/>
 */
@NoReturnParam
@RequiresParams(names = { "default", "type" })
public class Sort extends AbstractCommand {

    @Override
    public void execute(RuntimeConnector connector) {
        List list = (List) getVariableValue("default", connector);
        String propertyName = getVariableValueAsString("property", connector);
        String sortType = getVariableValueAsString("type", connector);
        String order = getVariableValueAsString("order", connector);

        Collections.sort(list, new HulaComparator(sortType, propertyName));

        if (order != null && order.equals("desc")) {
            Collections.reverse(list);
        }
    }

    public void validate(List<ParseError> errors) {
        ValidationUtil.assertParameterValueOneOf(this, errors, "type", "Alpha,Numeric");

        if (signatureParameters.containsKey("order")) {
            ValidationUtil.assertParameterValueOneOf(this, errors, "order", "asc,desc");
        }

    }

    class HulaComparator implements Comparator<Object> {
        String type = null;
        String property = null;

        public HulaComparator(String type, String property) {
            this.type = type;
            this.property = property;
        }

        @Override
        public int compare(Object left, Object right) {
            try {
                if (property != null) {
                    left = PropertyUtils.getProperty(left, property);
                    right = PropertyUtils.getProperty(right, property);
                }

                // if both null, return 0
                if (left == null && right == null) {
                    return 0;
                }

                else {

                    if (type.equals("Numeric")) {
                        BigDecimal leftnum = new BigDecimal(left.toString());
                        BigDecimal rightnum = new BigDecimal(right.toString());
                        return leftnum.compareTo(rightnum);
                    } else if (type.equals("Alpha")) {
                        return left.toString().compareTo(right.toString());
                    }

                }

                return 0;
            } catch (Throwable t) {
                throw new HulaRuntimeException("error.sorting.list", "error sorting list", t);
            }
        }

    }

}