at.porscheinformatik.common.spring.web.extended.util.ParboiledUtils.java Source code

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Here is the source code for at.porscheinformatik.common.spring.web.extended.util.ParboiledUtils.java

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/**
 * Copyright 2014 Daniel Furtlehner
 *
 * 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 at.porscheinformatik.common.spring.web.extended.util;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang.StringUtils;
import org.parboiled.errors.ParseError;
import org.parboiled.support.ParsingResult;
import org.springframework.util.Assert;

public class ParboiledUtils {

    public static <T> List<T> buildFromResult(ParsingResult<T> result, String resourceDescription) {
        Assert.notNull(result, "Got null Result while parsing template " + resourceDescription);

        if (result.hasErrors()) {
            throw new IllegalArgumentException(buildErrorMessag(result, resourceDescription));
        }

        Assert.isTrue(result.matched, "Template " + resourceDescription + " does not match the required format ");

        List<T> parts = new ArrayList<>(result.valueStack.size());

        for (T part : result.valueStack) {
            parts.add(0, part);
        }

        return parts;
    }

    private static <T> String buildErrorMessag(ParsingResult<T> result, String resourceDescription) {
        StringBuilder builder = new StringBuilder();
        builder.append("Template " + resourceDescription + " contains errors: \n");
        for (ParseError error : result.parseErrors) {
            int start = error.getStartIndex();
            int end = error.getEndIndex();

            if (start - 10 > 0) {
                start -= 10;
            } else {
                start = 0;
            }

            builder.append(error.getInputBuffer().extract(start, end)).append(" --> ");

            if (error.getErrorMessage() != null) {
                builder.append(error.getErrorMessage());
            } else {
                builder.append(error.toString());
            }

            builder.append("\n");

            builder.append(StringUtils.leftPad("^", error.getStartIndex() - start - 1));

            if (error.getEndIndex() > error.getStartIndex()) {
                builder.append(StringUtils.left("^", error.getEndIndex() - error.getStartIndex() - 1));
            }
        }

        return builder.toString();
    }
}