org.jeasy.rules.jexl.JexlRuleFactory Maven / Gradle / Ivy

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/*
 * The MIT License
 *
 *  Copyright (c) 2022, Mahmoud Ben Hassine ([email protected])
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *  THE SOFTWARE.
 */
package org.jeasy.rules.jexl;

import java.io.Reader;
import java.util.List;
import java.util.Objects;
import org.apache.commons.jexl3.JexlEngine;
import org.jeasy.rules.api.Rule;
import org.jeasy.rules.api.Rules;
import org.jeasy.rules.support.AbstractRuleFactory;
import org.jeasy.rules.support.RuleDefinition;
import org.jeasy.rules.support.reader.RuleDefinitionReader;

/**
 * @author Lauri Kimmel
 * @author Mahmoud Ben Hassine
 */
public class JexlRuleFactory extends AbstractRuleFactory {

  private final RuleDefinitionReader reader;
  private final JexlEngine jexl;

  public JexlRuleFactory(RuleDefinitionReader reader) {
    this(reader, JexlRule.DEFAULT_JEXL);
  }

  public JexlRuleFactory(RuleDefinitionReader reader, JexlEngine jexl) {
    this.reader = Objects.requireNonNull(reader, "reader cannot be null");
    this.jexl = Objects.requireNonNull(jexl, "Jexl Engine cannot be null");
  }

  public Rule createRule(Reader ruleDescriptor) throws Exception {
    Objects.requireNonNull(ruleDescriptor, "ruleDescriptor cannot be null");
    Objects.requireNonNull(jexl, "jexl cannot be null");
    List ruleDefinitions = reader.read(ruleDescriptor);
    if (ruleDefinitions.isEmpty()) {
      throw new IllegalArgumentException("rule descriptor is empty");
    }
    return createRule(ruleDefinitions.get(0));
  }

  public Rules createRules(Reader rulesDescriptor) throws Exception {
    Objects.requireNonNull(rulesDescriptor, "rulesDescriptor cannot be null");
    Rules rules = new Rules();
    List ruleDefinitions = reader.read(rulesDescriptor);
    for (RuleDefinition ruleDefinition : ruleDefinitions) {
      rules.register(createRule(ruleDefinition));
    }
    return rules;
  }

  @Override
  protected Rule createSimpleRule(RuleDefinition ruleDefinition) {
    Objects.requireNonNull(ruleDefinition, "ruleDefinition cannot be null");
    JexlRule rule =
        new JexlRule(jexl)
            .name(ruleDefinition.getName())
            .description(ruleDefinition.getDescription())
            .priority(ruleDefinition.getPriority())
            .when(ruleDefinition.getCondition());
    for (String action : ruleDefinition.getActions()) {
      rule.then(action);
    }
    return rule;
  }
}