/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.apache.commons.jxpath.ri.compiler;
  
  import org.apache.commons.jxpath.ri.Compiler;
  import org.apache.commons.jxpath.ri.QName;
  
  /**
   * @author Dmitri Plotnikov
   * @version $Revision: 652845 $ $Date: 2008-05-02 19:46:46 +0200 (Fr, 02 Mai 2008) $
   */
  public class TreeCompiler implements Compiler {
  
      private static final QName QNAME_NAME = new QName(null, "name");
  
      public Object number(String value) {
          return new Constant(new Double(value));
      }
  
      public Object literal(String value) {
          return new Constant(value);
      }
  
      public Object qname(String prefix, String name) {
          return new QName(prefix, name);
      }
  
      public Object sum(Object[] arguments) {
          return new CoreOperationAdd(toExpressionArray(arguments));
      }
  
      public Object minus(Object left, Object right) {
          return new CoreOperationSubtract(
              (Expression) left,
              (Expression) right);
      }
  
      public Object multiply(Object left, Object right) {
          return new CoreOperationMultiply((Expression) left, (Expression) right);
      }
  
      public Object divide(Object left, Object right) {
          return new CoreOperationDivide((Expression) left, (Expression) right);
      }
  
      public Object mod(Object left, Object right) {
          return new CoreOperationMod((Expression) left, (Expression) right);
      }
  
      public Object lessThan(Object left, Object right) {
          return new CoreOperationLessThan((Expression) left, (Expression) right);
      }
  
      public Object lessThanOrEqual(Object left, Object right) {
          return new CoreOperationLessThanOrEqual(
              (Expression) left,
              (Expression) right);
      }
  
      public Object greaterThan(Object left, Object right) {
          return new CoreOperationGreaterThan(
              (Expression) left,
              (Expression) right);
      }
  
      public Object greaterThanOrEqual(Object left, Object right) {
          return new CoreOperationGreaterThanOrEqual(
              (Expression) left,
              (Expression) right);
      }
  
      public Object equal(Object left, Object right) {
          return isNameAttributeTest((Expression) left)
                  ? new NameAttributeTest((Expression) left, (Expression) right)
                  : new CoreOperationEqual((Expression) left, (Expression) right);
      }
  
      public Object notEqual(Object left, Object right) {
          return new CoreOperationNotEqual((Expression) left, (Expression) right);
      }
  
      public Object minus(Object argument) {
          return new CoreOperationNegate((Expression) argument);
      }
  
     public Object variableReference(Object qName) {
         return new VariableReference((QName) qName);
     }
 
     public Object function(int code, Object[] args) {
         return new CoreFunction(code, toExpressionArray(args));
     }
 
     public Object function(Object name, Object[] args) {
         return new ExtensionFunction((QName) name, toExpressionArray(args));
     }
 
     public Object and(Object[] arguments) {
         return new CoreOperationAnd(toExpressionArray(arguments));
     }
 
     public Object or(Object[] arguments) {
         return new CoreOperationOr(toExpressionArray(arguments));
     }
 
     public Object union(Object[] arguments) {
         return new CoreOperationUnion(toExpressionArray(arguments));
     }
 
     public Object locationPath(boolean absolute, Object[] steps) {
         return new LocationPath(absolute, toStepArray(steps));
     }
 
     public Object expressionPath(Object expression, Object[] predicates,
             Object[] steps) {
         return new ExpressionPath(
             (Expression) expression,
             toExpressionArray(predicates),
             toStepArray(steps));
     }
 
     public Object nodeNameTest(Object qname) {
         return new NodeNameTest((QName) qname);
     }
 
     public Object nodeTypeTest(int nodeType) {
         return new NodeTypeTest(nodeType);
     }
 
     public Object processingInstructionTest(String instruction) {
         return new ProcessingInstructionTest(instruction);
     }
 
     public Object step(int axis, Object nodeTest, Object[] predicates) {
         return new Step(
             axis,
             (NodeTest) nodeTest,
             toExpressionArray(predicates));
     }
 
     /**
      * Get an Object[] as an Expression[].
      * @param array Object[]
      * @return Expression[]
      */
     private Expression[] toExpressionArray(Object[] array) {
         Expression[] expArray = null;
         if (array != null) {
             expArray = new Expression[array.length];
             for (int i = 0; i < expArray.length; i++) {
                 expArray[i] = (Expression) array[i];
             }
         }
         return expArray;
     }
 
     /**
      * Get an Object[] as a Step[].
      * @param array Object[]
      * @return Step[]
      */
     private Step[] toStepArray(Object[] array) {
         Step[] stepArray = null;
         if (array != null) {
             stepArray = new Step[array.length];
             for (int i = 0; i < stepArray.length; i++) {
                 stepArray[i] = (Step) array[i];
             }
         }
         return stepArray;
     }
 
     /**
      * Learn whether arg is a name attribute test.
      * @param arg Expression to test
      * @return boolean
      */
     private boolean isNameAttributeTest(Expression arg) {
         if (!(arg instanceof LocationPath)) {
             return false;
         }
 
         Step[] steps = ((LocationPath) arg).getSteps();
         if (steps.length != 1) {
             return false;
         }
         if (steps[0].getAxis() != Compiler.AXIS_ATTRIBUTE) {
             return false;
         }
         NodeTest test = steps[0].getNodeTest();
         if (!(test instanceof NodeNameTest)) {
             return false;
         }
         if (!((NodeNameTest) test).getNodeName().equals(QNAME_NAME)) {
             return false;
         }
         return true;
     }
 }