/*
    * Copyright 2004-2009 the original author or authors.
    *
    * 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.springmodules.validation.util.cel.ognl;
  
  import ognl.Ognl;
  import ognl.OgnlException;
  import org.springframework.util.Assert;
  import org.springmodules.validation.util.condition.AbstractCondition;
  import org.springmodules.validation.util.condition.Condition;
  import org.springmodules.validation.util.lang.NestedIllegalArgumentException;
  
  /**
   * A {@link Condition} that checks the given object based on a boolean OGNL expression.
   *
   * @author Uri Boness
   */
  public class OgnlCondition extends AbstractCondition {
  
      private String expression;
  
      private Object compiledExpression;
  
      /**
       * Constructs a new OgnlCondition with given OGNL boolean expression.
       *
       * @param expression The given OGNL boolean expression.
       */
      public OgnlCondition(String expression) {
          Assert.notNull(expression, "OGNL expression cannot be null");
          this.expression = expression;
          try {
              compiledExpression = Ognl.parseExpression(expression);
          } catch (OgnlException oe) {
              throw new NestedIllegalArgumentException("Could not parse OGNL boolean expression '" + expression + "'", oe);
          }
      }
  
      /**
       * @see AbstractCondition#doCheck(Object)
       */
      public boolean doCheck(Object object) {
          try {
              return ((Boolean) Ognl.getValue(compiledExpression, object, Boolean.class)).booleanValue();
          } catch (OgnlException e) {
              throw new IllegalArgumentException("Could not evaluate expression '" + expression +
                  "' on given object '" + String.valueOf(object) + "'");
          }
      }
  
  }