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/*
 * Based on JUEL 2.2.1 code, 2006-2009 Odysseus Software GmbH
 *
 * 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.activiti.engine.impl.juel;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

import org.activiti.engine.impl.javax.el.ELContext;
import org.activiti.engine.impl.javax.el.ELException;
import org.activiti.engine.impl.javax.el.MethodInfo;
import org.activiti.engine.impl.javax.el.MethodNotFoundException;
import org.activiti.engine.impl.javax.el.PropertyNotFoundException;
import org.activiti.engine.impl.javax.el.ValueExpression;
import org.activiti.engine.impl.javax.el.ValueReference;

public class AstIdentifier extends AstNode implements IdentifierNode {
  private final String name;
  private final int index;

  public AstIdentifier(String name, int index) {
    this.name = name;
    this.index = index;
  }

  public Class getType(Bindings bindings, ELContext context) {
    ValueExpression expression = bindings.getVariable(index);
    if (expression != null) {
      return expression.getType(context);
    }
    context.setPropertyResolved(false);
    Class result = context.getELResolver().getType(context, null, name);
    if (!context.isPropertyResolved()) {
      throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
    }
    return result;
  }

  public boolean isLeftValue() {
    return true;
  }

  public boolean isMethodInvocation() {
    return false;
  }

  public boolean isLiteralText() {
    return false;
  }

  public ValueReference getValueReference(Bindings bindings, ELContext context) {
    ValueExpression expression = bindings.getVariable(index);
    if (expression != null) {
      return expression.getValueReference(context);
    }
    return new ValueReference(null, name);
  }

  @Override
  public Object eval(Bindings bindings, ELContext context) {
    ValueExpression expression = bindings.getVariable(index);
    if (expression != null) {
      return expression.getValue(context);
    }
    context.setPropertyResolved(false);
    Object result = context.getELResolver().getValue(context, null, name);
    if (!context.isPropertyResolved()) {
      throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
    }
    return result;
  }

  public void setValue(Bindings bindings, ELContext context, Object value) {
    ValueExpression expression = bindings.getVariable(index);
    if (expression != null) {
      expression.setValue(context, value);
      return;
    }
    context.setPropertyResolved(false);
    context.getELResolver().setValue(context, null, name, value);
    if (!context.isPropertyResolved()) {
      throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
    }
  }

  public boolean isReadOnly(Bindings bindings, ELContext context) {
    ValueExpression expression = bindings.getVariable(index);
    if (expression != null) {
      return expression.isReadOnly(context);
    }
    context.setPropertyResolved(false);
    boolean result = context.getELResolver().isReadOnly(context, null, name);
    if (!context.isPropertyResolved()) {
      throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
    }
    return result;
  }

  protected Method getMethod(Bindings bindings, ELContext context, Class returnType, Class[] paramTypes) {
    Object value = eval(bindings, context);
    if (value == null) {
      throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
    }
    if (value instanceof Method) {
      Method method = (Method) value;
      if (returnType != null && !returnType.isAssignableFrom(method.getReturnType())) {
        throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
      }
      if (!Arrays.equals(method.getParameterTypes(), paramTypes)) {
        throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
      }
      return method;
    }
    throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notamethod", name, value.getClass()));
  }

  public MethodInfo getMethodInfo(Bindings bindings, ELContext context, Class returnType, Class[] paramTypes) {
    Method method = getMethod(bindings, context, returnType, paramTypes);
    return new MethodInfo(method.getName(), method.getReturnType(), paramTypes);
  }

  public Object invoke(Bindings bindings, ELContext context, Class returnType, Class[] paramTypes, Object[] params) {
    Method method = getMethod(bindings, context, returnType, paramTypes);
    try {
      return method.invoke(null, params);
    } catch (IllegalAccessException e) {
      throw new ELException(LocalMessages.get("error.identifier.method.access", name));
    } catch (IllegalArgumentException e) {
      throw new ELException(LocalMessages.get("error.identifier.method.invocation", name, e));
    } catch (InvocationTargetException e) {
      throw new ELException(LocalMessages.get("error.identifier.method.invocation", name, e.getCause()));
    }
  }

  @Override
  public String toString() {
    return name;
  }

  @Override
  public void appendStructure(StringBuilder b, Bindings bindings) {
    b.append(bindings != null && bindings.isVariableBound(index) ? "" : name);
  }

  public int getIndex() {
    return index;
  }

  public String getName() {
    return name;
  }

  public int getCardinality() {
    return 0;
  }

  public AstNode getChild(int i) {
    return null;
  }
}