FileConverter.java

/*
 * Copyright (c) 2001-2007, Inversoft Inc., 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 org.primeframework.mvc.parameter.convert.converters;

import java.io.File;
import java.lang.reflect.Type;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;
import org.primeframework.mvc.parameter.convert.AbstractGlobalConverter;
import org.primeframework.mvc.parameter.convert.ConversionException;
import org.primeframework.mvc.parameter.convert.ConverterStateException;
import org.primeframework.mvc.parameter.convert.annotation.GlobalConverter;

/**
 * This class converts to and from the java.io.File class.
 *
 * @author Brian Pontarelli
 */
@GlobalConverter
public class FileConverter extends AbstractGlobalConverter {
  /**
   * Returns null if the value is null, otherwise this returns a new File of the value.
   *
   * @param attributes Can contain the parentDir attribute which if the String is relative will
   * @param expression No used.
   */
  protected Object stringToObject(String value, Type convertTo, Map<String, String> attributes, String expression)
    throws ConversionException, ConverterStateException {
    if (StringUtils.isBlank(value)) {
      return null;
    }

    if (value.charAt(0) == File.separatorChar || value.charAt(0) == '\\') {
      return new File(value);
    }

    if (attributes != null) {
      String parent = attributes.get("parentDir");
      if (parent != null) {
        return new File(parent, value);
      }
    }

    return new File(value);
  }

  /**
   * Joins the values and then sends the new joined String to the stringToObject method.
   */
  protected Object stringsToObject(String[] values, Type convertTo, Map<String, String> attributes, String expression)
    throws ConversionException, ConverterStateException {
    String joined = StringUtils.join(values, File.separator);
    return stringToObject(joined, convertTo, attributes, expression);
  }

  /**
   * Returns the absolute path of the file.
   */
  protected String objectToString(Object value, Type convertFrom, Map<String, String> attributes, String expression)
    throws ConversionException, ConverterStateException {
    File file = (File) value;
    return file.getAbsolutePath();
  }
}