com.mgmtp.jfunk.data.generator.constraint.FromTo.java Source code

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Here is the source code for com.mgmtp.jfunk.data.generator.constraint.FromTo.java

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/*
 * Copyright (c) 2015 mgm technology partners GmbH
 *
 * 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.mgmtp.jfunk.data.generator.constraint;

import java.util.Collections;
import java.util.List;

import org.jdom.Element;

import com.google.common.collect.Lists;
import com.mgmtp.jfunk.common.random.MathRandom;
import com.mgmtp.jfunk.data.generator.Generator;
import com.mgmtp.jfunk.data.generator.control.FieldCase;

/**
 * This complex constraint generates values for its sub-constraints so that they are in ascending
 * order. After 10000 unsuccessful tries an exception is thrown.
 * <p>
 * Example:
 * 
 * <pre>
 * {@code 
 * <constraint id="c0" class="com.mgmtp.jfunk.data.generator.constraint.FromTo">
 *   <constraint id="c1">
 *     <field>
 *       <value>A</value>
 *       <value>B</value>
 *       <value>C</value>
 *     </field>
 *   </constraint>
 *   <constraint id="c2">
 *     <field>
 *       <value>A</value>
 *       <value>B</value>
 *       <value>C</value>
 *     </field>
 *   </constraint>
 * </constraint>
 * }
 * </pre>
 * 
 * The constraints c1 and c2 are not generated individually anymore but considered as a unit such
 * that c1 combined with c2 always is "ascending". Generated values would be:
 * <table>
 * <tr>
 * <th>c1</th>
 * <td>A</td>
 * <td>A</td>
 * <td>A</td>
 * <td>B</td>
 * <td>B</td>
 * <td>C</td>
 * </tr>
 * <tr>
 * <th>c2</th>
 * <td>A</td>
 * <td>B</td>
 * <td>C</td>
 * <td>B</td>
 * <td>C</td>
 * <td>C</td>
 * </tr>
 * </table>
 * Please note that constraint c0 does not have a value, {@link #initValues(FieldCase)} always
 * returns {@code null}.
 * 
 */
public class FromTo extends Complex {
    public FromTo(final MathRandom random, final Element el, final Generator generator) {
        super(random, el, generator);
    }

    /**
     * @return always null - only affects the values of the sub-constraints.
     */
    @Override
    public String initValues(final FieldCase c) {
        List<String> lastValues = Lists.newArrayListWithCapacity(constraints.size());
        List<String> values = Lists.newArrayListWithCapacity(constraints.size());
        List<String> sortedValues = Lists.newArrayListWithCapacity(constraints.size());
        int generate = 10000;
        int equalsCount = 0;
        while (generate > 0) {
            super.initValues(c);
            for (Constraint constraint : constraints) {
                String s = constraint.initValues(c);
                if (s != null) {
                    values.add(s);
                }
            }
            if (values.isEmpty()) {
                break;
            }
            sortedValues.addAll(values);
            Collections.sort(sortedValues);
            if (values.equals(sortedValues)) {
                break;
            }
            if (values.equals(lastValues)) {
                equalsCount++;
            } else {
                equalsCount = 0;
            }
            if (equalsCount == 5) {
                log.debug("Generated values were equal in a row for five times und thus can be assumed as fixed");
                break;
            }
            lastValues.clear();
            lastValues.addAll(values);
            values.clear();
            sortedValues.clear();
            resetValues();
            generate--;
        }
        if (generate == 0) {
            throw new IllegalStateException("Could not generate values in ascending order after 10000 tries");
        }
        return null;
    }
}