de.codesourcery.spring.contextrewrite.AnnotationParser.java Source code

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Here is the source code for de.codesourcery.spring.contextrewrite.AnnotationParser.java

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/**
 * Copyright 2015 Tobias Gierke <tobias.gierke@code-sourcery.de>
 *
 * 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 de.codesourcery.spring.contextrewrite;

import java.util.NoSuchElementException;
import java.util.Optional;

import org.apache.commons.lang3.Validate;

import de.codesourcery.spring.contextrewrite.ContextRewritingBootStrapper.ContextConfiguration;
import de.codesourcery.spring.contextrewrite.ContextRewritingBootStrapper.InsertAttributeRule;
import de.codesourcery.spring.contextrewrite.ContextRewritingBootStrapper.InsertElementRule;
import de.codesourcery.spring.contextrewrite.ContextRewritingBootStrapper.RemoveRule;
import de.codesourcery.spring.contextrewrite.ContextRewritingBootStrapper.ReplaceRule;

/**
 * Populates a <code>RewriteConfig</code> by gathering XML rewrite annotations from a class hierarchy. 
 *
 * @author tobias.gierke@code-sourcery.de
 */
public class AnnotationParser {
    /**
     * Parse rewrite annotations.
     * 
     * @param clazz class whose annotations should be parsed. This method will also parse parent classes and merge any rewriting annotations it encounters 
     *             according to the rules described in {@link RewriteConfig#getRules()}.
     *               
     * @return rewriting configuration
     * @throws NoSuchElementException if neither the input class nor any of its parents had a {@link ContextConfiguration} annotation.
     */
    public RewriteConfig parse(Class<?> clazz) throws NoSuchElementException {
        Validate.notNull(clazz, "clazz must not be NULL");

        RewriteConfig first = null;
        RewriteConfig previous = null;
        Class<?> currentClass = clazz;
        while (currentClass != Object.class) {
            final Optional<ContextConfiguration> ctxConfiguration = Optional
                    .ofNullable(currentClass.getAnnotation(ContextConfiguration.class));

            final RewriteConfig config = new RewriteConfig(currentClass);

            if (ctxConfiguration.isPresent()) {
                config.setContextPath(ctxConfiguration.get().value());
                config.setDebug(ctxConfiguration.get().debug());
                config.setDumpXML(ctxConfiguration.get().dumpRewrittenXML());
            }

            config.addRules(XMLRewrite.wrap(currentClass.getAnnotationsByType(ReplaceRule.class)));
            config.addRules(XMLRewrite.wrap(currentClass.getAnnotationsByType(RemoveRule.class)));
            config.addRules(XMLRewrite.wrap(currentClass.getAnnotationsByType(InsertElementRule.class)));
            config.addRules(XMLRewrite.wrap(currentClass.getAnnotationsByType(InsertAttributeRule.class)));

            if (ctxConfiguration.isPresent() || config.hasRules()) {
                if (previous != null) {
                    previous.setParent(config);
                }
                previous = config;

                if (first == null) {
                    first = config;
                }
            }
            currentClass = currentClass.getSuperclass();
        }
        if (first == null) {
            throw new NoSuchElementException("Found no @" + ContextConfiguration.class.getName() + " annotation on "
                    + clazz.getName() + " or any of its super classes");
        }
        return first;
    }
}