maven-model-transform/src/main/java/org/apache/maven/model/transform/FastForwardFilter.java

package org.apache.maven.model.transform;

/*
 * 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.
 */

import java.io.IOException;
import java.util.ArrayDeque;
import java.util.Deque;

import org.apache.maven.model.transform.pull.BufferingParser;
import org.codehaus.plexus.util.xml.pull.XmlPullParser;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;

/**
 * This filter will skip all following filters and write directly to the output.
 * Should be used in case of a DOM that should not be effected by other filters, even though the elements match.
 *
 * @author Robert Scholte
 * @author Guillaume Nodet
 * @since 4.0.0
 */
class FastForwardFilter extends BufferingParser
{
    /**
     * DOM elements of pom
     *
     * <ul>
     *  <li>execution.configuration</li>
     *  <li>plugin.configuration</li>
     *  <li>plugin.goals</li>
     *  <li>profile.reports</li>
     *  <li>project.reports</li>
     *  <li>reportSet.configuration</li>
     * <ul>
     */
    private final Deque<String> state = new ArrayDeque<>();

    private int domDepth = 0;

    FastForwardFilter( XmlPullParser xmlPullParser )
    {
        super( xmlPullParser );
    }

    @Override
    protected boolean accept() throws XmlPullParserException, IOException
    {
        if ( xmlPullParser.getEventType() == START_TAG )
        {
            String localName = xmlPullParser.getName();
            if ( domDepth > 0 )
            {
                domDepth++;
            }
            else
            {
                final String key = state.peek() + '/' + localName;
                switch ( key )
                {
                    case "execution/configuration":
                    case "plugin/configuration":
                    case "plugin/goals":
                    case "profile/reports":
                    case "project/reports":
                    case "reportSet/configuration":
                        domDepth++;
                        disable();
                        break;
                    default:
                        break;
                }
            }
            state.add( localName );
        }
        else if ( xmlPullParser.getEventType() == END_TAG )
        {
            domDepth--;
            if ( domDepth == 0 )
            {
                enable();
            }
            state.pop();
        }
        return true;
    }

}