enforcer-rules/src/main/java/org/apache/maven/plugins/enforcer/RequireFilesExist.java

package org.apache.maven.plugins.enforcer;

/*
 * 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.File;
import java.io.IOException;

/**
 * The Class RequireFilesExist.
 */
public class RequireFilesExist
    extends AbstractRequireFiles
{
    @Override
    boolean checkFile( File file )
    {
        // if we get here and the handle is null, treat it as a success
        return file == null ? true : file.exists() && osIndependentNameMatch( file, true );
    }

    @Override
    String getErrorMsg()
    {
        return "Some required files are missing:" + System.lineSeparator();
    }

    /**
     * OSes like Windows are case insensitive, so this method will compare the file path with the actual path. A simple
     * {@link File#exists()} is not enough for such OS.
     * 
     * @param file the file to verify
     * @param defaultValue value to return in case an IO exception occurs, should never happen as the file already
     *            exists
     * @return
     */
    private boolean osIndependentNameMatch( File file, boolean defaultValue )
    {
        try
        {
            File absFile;
            if ( !file.isAbsolute() )
            {
                absFile = new File( new File( "." ).getCanonicalFile(), file.getPath() );
            }
            else
            {
                absFile = file;
            }

            return absFile.toURI().equals( absFile.getCanonicalFile().toURI() );
        }
        catch ( IOException e )
        {
            return defaultValue;
        }
    }
}