/*
    * Copyright 2004-2005 Germinus XXI
    *
    * 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.germinus.easyconf;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /***
   * Builds filters from arrays of strings or up to three string paramters
   * 
   * @author jferrer
   */
  public class Filter {
  
      private String[] selectors;
      private Map variables;
  
      // ............. Constructors ................
      
      private Filter(String[] selectors) {
          this.selectors = selectors;
      }
      private Filter(Map variables) {
          this.variables = variables;
      }
  
      
      // ......... static methods ...........
      
      public static Filter by(String first) {
          return new Filter(new String[]{first});
      }
  
      public static Filter by(String first, String second) {
          return new Filter(new String[]{first, second});
      }
  
      public static Filter by(String first, String second, String third) {
          return new Filter(new String[]{first, second, third});
      }
      
      public static Filter by(String[] selectors) {
          return new Filter(selectors);
      }
  
      public static Filter usingVariables(String var1, String value1) {
          Map vars = new HashMap();
          vars.put(var1, value1);
          return new Filter(vars);
      }
      public static Filter usingVariables(String var1, String value1, 
                                          String var2, String value2) {
          Map vars = new HashMap();
          vars.put(var1, value1);
          vars.put(var2, value2);
          return new Filter(vars);
      }
      public static Filter usingVariables(String var1, String value1, 
                                          String var2, String value2,
                                          String var3, String value3) {
          Map vars = new HashMap();
          vars.put(var1, value1);
          vars.put(var2, value2);
          vars.put(var3, value3);
          return new Filter(vars);
      }
      public static Filter usingVariables(Map vars) {
          return new Filter(vars);
      }
  
      // .............. instance methods ................
      
      public boolean hasVariables() {
          return (variables != null) && (!variables.isEmpty());
      }
  
      public Filter setVariables(Map newVars) {
          this.variables = newVars;
          return this;
      }
      public Map getVariables() {
          return variables;
      }
  
      public String[] getSelectors() {
          return selectors;
     }
     
     public Filter setSelectors(String[] newSelectors) {
         this.selectors = newSelectors;
         return this;
     }
     
     public int numOfSelectors() {
         if (selectors == null) {
             return 0;
         }
         return selectors.length;
     }
 
     /***
      * Get a fragment of the filter which includes the first 'n' selectors
      * concatenated.
      *
      * Example: if the filter has two selectors (bar and foo). Fragments would
      * be:
      * <ul>
      *  <li>For n=2: "[bar][foo]"
      *  <li>For n=1: "[bar]"
      *  <li>For n=0: ""
      *  <li>Otherwise: throws IllegalArgumentException
      * </ul>
      * @param n
      * @return
      * @throws IllegalArgumentException if n < 1 or n > size()
      */
     public String getFilterSuffix(int n) {
         if ((n<0) || (n > numOfSelectors())) {
             throw new IllegalArgumentException("Imposible to obtain filter fragment for n="+n);
         }
         if (n==0) {
             return "";
         }
         StringBuffer filter = new StringBuffer();
         for (int i = 0; i < n; i++) {
             filter.append(Conventions.SELECTOR_START);
             filter.append(selectors[i]);
             filter.append(Conventions.SELECTOR_END);
         }
         return filter.toString();
     }
 
     public String toString() {
         return getFilterSuffix(numOfSelectors());
     }
 
 
 }