org.parboiled.Parboiled Maven / Gradle / Ivy
/*
* Copyright (C) 2009-2011 Mathias Doenitz
*
* 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.parboiled;
import static org.parboiled.common.Preconditions.*;
import org.parboiled.transform.ParserTransformer;
import java.lang.reflect.Constructor;
import static org.parboiled.common.Utils.findConstructor;
/**
* Main class providing the high-level entry point into the parboiled library.
*/
public class Parboiled {
protected Parboiled() {}
/**
* Creates a parser object whose rule creation methods can then be used with one of the {@link org.parboiled.parserunners.ParseRunner} implementations.
* Since parboiled needs to extend your parser with certain extra logic (e.g. to prevent infinite recursions
* in recursive rule definitions) you cannot create your parser object yourself, but have to go through this method.
* Also your parser class has to be derived from {@link BaseParser}. If you want to use a non-default constructor
* you can provide its arguments to this method. Make sure your non-default constructor does not use primitive
* type parameters (like "int") but rather their boxed counterparts (like "Integer"), otherwise the constructor
* will not be found.
* Performing the rule analysis and extending the parser class is an expensive process (time-wise) and can
* take up to several hundred milliseconds for large grammars. However, this cost is only incurred once per
* parser class and class loader. Subsequent calls to this method are therefore fast once the initial extension
* has been performed.
*
* @param parserClass the type of the parser to create
* @param constructorArgs optional arguments to the parser class constructor
* @return the ready to use parser instance
*/
@SuppressWarnings({"unchecked"})
public static , V> P createParser(Class
parserClass, Object... constructorArgs) {
checkArgNotNull(parserClass, "parserClass");
try {
Class extendedClass = ParserTransformer.transformParser(parserClass);
Constructor constructor = findConstructor(extendedClass, constructorArgs);
return (P) constructor.newInstance(constructorArgs);
} catch (Exception e) {
throw new RuntimeException("Error creating extended parser class: " + e.getMessage(), e);
}
}
}