SimpleRuleStore.java

/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2013, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.joran.spi;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import ch.qos.logback.core.Context;
import ch.qos.logback.core.joran.action.Action;
import ch.qos.logback.core.spi.ContextAwareBase;
import ch.qos.logback.core.util.OptionHelper;

/**
 * This class implements the {@link RuleStore} interface. It is the rule store
 * implementation used by default in Joran.
 * 
 * @author Ceki Gülcü
 * 
 */
public class SimpleRuleStore extends ContextAwareBase implements RuleStore {

  static String KLEENE_STAR = "*";
  
  // key: Pattern instance, value: ArrayList containing actions
  HashMap<ElementSelector, List<Action>> rules = new HashMap<ElementSelector, List<Action>>();

  // public SimpleRuleStore() {
  // }

  public SimpleRuleStore(Context context) {
    setContext(context);
  }

  /**
   * Add a new rule, i.e. a pattern, action pair to the rule store. <p> Note
   * that the added action's LoggerRepository will be set in the process.
   */
  public void addRule(ElementSelector elementSelector, Action action) {
    action.setContext(context);

    List<Action> a4p = rules.get(elementSelector);

    if (a4p == null) {
      a4p = new ArrayList<Action>();
      rules.put(elementSelector, a4p);
    }

    a4p.add(action);
  }

  public void addRule(ElementSelector elementSelector, String actionClassName) {
    Action action = null;

    try {
      action = (Action) OptionHelper.instantiateByClassName(actionClassName,
          Action.class, context);
    } catch (Exception e) {
      addError("Could not instantiate class [" + actionClassName + "]", e);
    }
    if (action != null) {
      addRule(elementSelector, action);
    }
  }

  // exact match has highest priority
  // if no exact match, check for suffix (tail) match, i.e matches
  // of type */x/y. Suffix match for */x/y has higher priority than match for
  // */x
  // if no suffix match, check for prefix match, i.e. matches for x/*
  // match for x/y/* has higher priority than matches for x/*

  public List<Action> matchActions(ElementPath elementPath) {
    List<Action> actionList;

    if ((actionList = fullPathMatch(elementPath)) != null) {
      return actionList;
    } else if ((actionList = suffixMatch(elementPath)) != null) {
      return actionList;
    } else if ((actionList = prefixMatch(elementPath)) != null) {
      return actionList;
    } else if ((actionList = middleMatch(elementPath)) != null) {
      return actionList;
    } else {
      return null;
    }
  }

  List<Action> fullPathMatch(ElementPath elementPath) {
    for (ElementSelector selector : rules.keySet()) {
       if(selector.fullPathMatch(elementPath))
         return rules.get(selector);
    }
    return null;
  }

  // Suffix matches are matches of type */x/y
  List<Action> suffixMatch(ElementPath elementPath) {
    int max = 0;
    ElementSelector longestMatchingElementSelector = null;

    for (ElementSelector selector : rules.keySet()) {
      if (isSuffixPattern(selector)) {
        int r = selector.getTailMatchLength(elementPath);
        if (r > max) {
          max = r;
          longestMatchingElementSelector = selector;
        }
      }
    }

    if (longestMatchingElementSelector != null) {
      return rules.get(longestMatchingElementSelector);
    } else {
      return null;
    }
  }

  private boolean isSuffixPattern(ElementSelector p) {
    return (p.size() > 1) && p.get(0).equals(KLEENE_STAR);
  }

  List<Action> prefixMatch(ElementPath elementPath) {
    int max = 0;
    ElementSelector longestMatchingElementSelector = null;

    for (ElementSelector selector : rules.keySet()) {
      String last = selector.peekLast();
      if (isKleeneStar(last)) {
        int r = selector.getPrefixMatchLength(elementPath);
        // to qualify the match length must equal p's size omitting the '*'
        if ((r == selector.size() - 1) && (r > max)) {
          max = r;
          longestMatchingElementSelector = selector;
        }
      }
    }

    if (longestMatchingElementSelector != null) {
      return rules.get(longestMatchingElementSelector);
    } else {
      return null;
    }
  }

  private boolean isKleeneStar(String last) {
    return KLEENE_STAR.equals(last);
  }

  List<Action> middleMatch(ElementPath path) {
    
    int max = 0;
    ElementSelector longestMatchingElementSelector = null;

    for (ElementSelector selector : rules.keySet()) {
      String last = selector.peekLast();
      String first = null;
      if(selector.size() > 1) {
        first = selector.get(0);
      }
      if (isKleeneStar(last) && isKleeneStar(first)) {
        List<String> copyOfPartList = selector.getCopyOfPartList();
        if(copyOfPartList.size() > 2) {
          copyOfPartList.remove(0);
          copyOfPartList.remove(copyOfPartList.size()-1);
        }
        
        int r = 0;
        ElementSelector clone = new ElementSelector(copyOfPartList);
        if(clone.isContainedIn(path)) {
          r = clone.size();
        }
        if (r > max) {
          max = r;
          longestMatchingElementSelector = selector;
        }
      }
    }

    if (longestMatchingElementSelector != null) {
      return rules.get(longestMatchingElementSelector);
    } else {
      return null;
    }
  }
  

  public String toString() {
    final String TAB = "  ";

    StringBuilder retValue = new StringBuilder();

    retValue.append("SimpleRuleStore ( ").append("rules = ").append(this.rules)
        .append(TAB).append(" )");

    return retValue.toString();
  }

}