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'rapiddweller Script' is an open source software library for resolving Java-like script expressions, forked from Databene Scripts written by Volker Bergmann.

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/*
 * Copyright (C) 2011-2014 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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 com.rapiddweller.script;

import com.rapiddweller.commons.ArrayFormat;
import com.rapiddweller.commons.ArrayUtil;
import com.rapiddweller.commons.ConfigurationError;
import com.rapiddweller.commons.Context;
import com.rapiddweller.commons.ObjectNotFoundException;
import com.rapiddweller.commons.accessor.FeatureAccessor;
import com.rapiddweller.commons.bean.DefaultClassProvider;
import com.rapiddweller.script.expression.DynamicExpression;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;

/**
 * {@link Expression} implementation that evaluates a qualified name as attributes of an object reference or 
 * static fields of a Java class.

 * 

 * Created at 08.10.2009 07:18:53
 * @since 0.6.0
 * @author Volker Bergmann
 */

public class QNExpression extends DynamicExpression {

	private static final Logger LOGGER = LogManager.getLogger(DatabeneScriptParser.class);
	
	private String[] qnParts;
	
	public QNExpression(String[] qnParts) {
	    this.qnParts = qnParts;
    }

    @Override
	public Object evaluate(Context context) {
    	try {
    		return resolveNamePart(qnParts, qnParts.length, context);
    	} catch (ObjectNotFoundException e) {
    		throw new ObjectNotFoundException("Unable to resolve " + ArrayFormat.format(".", qnParts));
    	}
    }

    public static Object resolveNamePart(String[] qnParts, int qnLength, Context context) {
    	String objectOrClassName = ArrayFormat.formatPart(".", 0, qnLength, qnParts);
    	if (context.contains(objectOrClassName)) {
    		return context.get(objectOrClassName);
    	} else {
    		try {
    			return DefaultClassProvider.resolveByObjectOrDefaultInstance(objectOrClassName, context);
    		} catch (ConfigurationError e) {
    			// ignore errors signaling that a class was not found
    		}
			LOGGER.debug("Class not found: {}", objectOrClassName);
			if (qnLength > 1) {
    			return readField(qnParts, qnLength - 1, qnParts[qnLength - 1], context);
			} else
				throw new ObjectNotFoundException("'" + objectOrClassName + "' is not defined");
    	}
    }

    private static Object readField(String[] qnParts, int qnLength, String fieldName, Context context) {
    	return FeatureAccessor.getValue(resolveNamePart(qnParts, qnLength, context), fieldName);
    }

	public BeanSpec resolve(Context context) {
        String qn = ArrayFormat.format(".", qnParts);
        if (context.contains(qn)) {
        	return BeanSpec.createReference(context.get(qn));
        } else {
    		try {
    			Class bean = DefaultClassProvider.resolveByObjectOrDefaultInstance(qn, context);
				return BeanSpec.createConstruction(bean);
    		} catch (ConfigurationError e) {
    			// ignore this
    		}
			LOGGER.debug("Class not found: {}", qn);
	    	Object bean = readField(qnParts, qnParts.length - 1, ArrayUtil.lastElementOf(qnParts), context);
			return BeanSpec.createReference(bean);
        }
	}
    
    @Override
    public String toString() {
        return ArrayFormat.format(".", qnParts);
    }

}

    

    

    

            

    

            



    
    






    
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