Examples of org.camunda.bpm.engine.impl.javax.el.ValueExpression

Package org.camunda.bpm.engine.impl.javax.el

Examples of org.camunda.bpm.engine.impl.javax.el.ValueExpression

org.camunda.bpm.engine.impl.javax.el.ValueExpression
An Expression that can get or set a value. In previous incarnations of this API, expressions could only be read. ValueExpression objects can now be used both to retrieve a value and to set a value. Expressions that can have a value set on them are referred to as l-value expressions. Those that cannot are referred to as r-value expressions. Not all r-value expressions can be used as l-value expressions (e.g. "${1+1}" or "${firstName} ${lastName}"). See the EL Specification for details. Expressions that cannot be used as l-values must always return true from isReadOnly(). The {@link ExpressionFactory#createValueExpression(ELContext,String,Class)}method can be used to parse an expression string and return a concrete instance of ValueExpression that encapsulates the parsed expression. The {@link FunctionMapper} is used atparse time, not evaluation time, so one is not needed to evaluate an expression using this class. However, the {@link ELContext} is needed at evaluation time. The {@link #getValue(ELContext)}, {@link #setValue(ELContext,Object)}, {@link #isReadOnly(ELContext)} and{@link #getType(ELContext)} methods will evaluate the expression each time they are called. The{@link ELResolver} in the ELContext is used to resolve the top-level variables and to determinethe behavior of the . and [] operators. For any of the four methods, the {@link ELResolver#getValue(ELContext,Object,Object)} method is used to resolve all propertiesup to but excluding the last one. This provides the base object. At the last resolution, the ValueExpression will call the corresponding {@link ELResolver#getValue(ELContext,Object,Object)}, {@link ELResolver#setValue(ELContext,Object,Object,Object)}, {@link ELResolver#isReadOnly(ELContext,Object,Object)} or{@link ELResolver#getType(ELContext,Object,Object)} method, depending on which was called onthe ValueExpression. See the notes about comparison, serialization and immutability in the {@link Expression} javadocs. @see ELResolver @see Expression @see ExpressionFactory

  public JuelScriptEngine() {
    this(null);
  }


  public Object eval(String script, ScriptContext scriptContext) throws ScriptException {
    ValueExpression expr = parse(script, scriptContext);
    return evaluateExpression(expr, scriptContext);
  }

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      return null;
    }


    @Override
    public ValueExpression setVariable(String name, ValueExpression value) {
      ValueExpression previousValue = resolveVariable(name);
      scriptContext.setAttribute(name, value, ScriptContext.ENGINE_SCOPE);
      return previousValue;
    }

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    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));

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  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);
  }

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    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));

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    }
    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()) {

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      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));

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    }
    ValueExpression[] expressions = null;
    if (identifiers.size() > 0) {
      expressions = new ValueExpression[identifiers.size()];
      for (IdentifierNode node: identifiers) {
        ValueExpression expression = null;
        if (varMapper != null) {
          expression = varMapper.resolveVariable(node.getName());
        }
        expressions[node.getIndex()] = expression;
      }

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    expressionFactory = new ExpressionFactoryImpl();
    this.beans = beans;
  }


  public Expression createExpression(String expression) {
    ValueExpression valueExpression = expressionFactory.createValueExpression(parsingElContext, expression, Object.class);
    return new JuelExpression(valueExpression, this, expression);
  }

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  }






  public Expression createExpression(String expression) {
    ValueExpression valueExpression = expressionFactory.createValueExpression(parsingElContext, expression, Object.class);
    return new JuelExpression(valueExpression, this, expression);
  }

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Related Classes of org.camunda.bpm.engine.impl.javax.el.ValueExpression

org.camunda.bpm.engine.impl.el.ExpressionManager

org.camunda.bpm.engine.impl.juel.AstIdentifier

org.camunda.bpm.engine.impl.juel.Tree

org.camunda.bpm.engine.impl.scripting.engine.JuelScriptEngine

org.camunda.bpm.engine.impl.scripting.engine.JuelScriptEngine$ScriptContextVariableMapper

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