org.jppf.node.policy.RegExp Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jppf-common Show documentation
JPPF, the open source grid computing solution
There is a newer version: 6.3-alpha
/*
 * JPPF.
 * Copyright (C) 2005-2015 JPPF Team.
 * http://www.jppf.org
 *
 * 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 org.jppf.node.policy;

import java.util.regex.*;

import org.jppf.utils.PropertiesCollection;

/**
 * An execution policy rule that encapsulates a test of type property_value matches regular_expression.
 * The expression syntax must follow the one specified for {@link java.util.regex.Pattern Pattern}.
 * The test applies to string values only.
 * @author Laurent Cohen
 */
public class RegExp extends ExecutionPolicy
{
  /**
   * Explicit serialVersionUID.
   */
  private static final long serialVersionUID = 1L;
  /**
   * The name of the property to compare.
   */
  private String propertyName = null;
  /**
   * A regular expression to match the property value against.
   */
  private String regExp = null;
  /**
   * The pattern object to compile from the regular expression.
   */
  private transient Pattern pattern = null;

  /**
   * Define an equality comparison between the string value of a property and another string value.
   * @param propertyName the name of the property to compare.
   * @param regExp a regular expression to match the property value against.
   * @throws PatternSyntaxException if the syntax of expression is invalid
   */
  public RegExp(final String propertyName, final String regExp) throws PatternSyntaxException
  {
    this.propertyName = propertyName;
    // compiled at creation time to ensure any syntax problem in the expression
    // is known on the client side.
    pattern = Pattern.compile(regExp);
    this.regExp = regExp;
  }

  /**
   * Determines whether this policy accepts the specified node.
   * @param info system information for the node on which the tasks will run if accepted.
   * @return true if the node is accepted, false otherwise.
   */
  @Override
  public boolean accepts(final PropertiesCollection info)
  {
    if (regExp == null) return false;
    // the pattern is cached so it doesn't have to be compiled every time.
    if (pattern == null) pattern = Pattern.compile(regExp);
    String s = getProperty(info, propertyName);
    if (s == null) return false;
    return pattern.matcher(s).matches();
  }

  /**
   * Print this object to a string.
   * @return an XML string representation of this object
   */
  @Override
  public String toString()
  {
    if (computedToString == null)
    {
      synchronized(ExecutionPolicy.class)
      {
        StringBuilder sb = new StringBuilder();
        sb.append(indent()).append("\n");
        toStringIndent++;
        sb.append(indent()).append("").append(propertyName).append("\n");
        sb.append(indent()).append("").append(regExp).append("\n");
        toStringIndent--;
        sb.append(indent()).append("\n");
        computedToString = sb.toString();
      }
    }
    return computedToString;
  }
}