org.apache.nifi.expression.ExpressionLanguageCompiler Maven / Gradle / Ivy
/*
* 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.nifi.expression;
import org.apache.nifi.expression.AttributeExpression.ResultType;
public interface ExpressionLanguageCompiler {
/**
* Compiles the given Attribute Expression string into an
* AttributeExpression that can be evaluated
*
* @param expression the Attribute Expression to be compiled
* @return expression that can be evaluated
* @throws IllegalArgumentException if the given expression is not valid
*/
AttributeExpression compile(String expression) throws IllegalArgumentException;
/**
* Indicates whether or not the given string is a valid Attribute
* Expression.
*
* @param expression to validate
* @return if is value or not
*/
boolean isValidExpression(String expression);
/**
* Attempts to validate the given expression and returns null
* if the expression is syntactically valid or a String indicating why the
* expression is invalid otherwise.
*
* @param expression to validate
* @param allowSurroundingCharacters if true allows characters
* to surround the Expression, otherwise the expression must be exactly
* equal to a valid Expression. E.g., /${path} is valid if and
* only if allowSurroundingCharacters is true
*
* @return a String indicating the reason that the expression is not
* syntactically correct, or null if the expression is
* syntactically correct
*/
String validateExpression(String expression, boolean allowSurroundingCharacters);
/**
* Returns the ResultType that will be returned by the given Expression
*
* @param expression the Expression to evaluate
* @return result type for the given expression
* @throws IllegalArgumentException if the given Expression is not a valid
* Expression Language Expression; the message of this Exception will
* indicate the problem if the expression is not syntactically valid.
*/
ResultType getResultType(String expression) throws IllegalArgumentException;
}