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/*
* Copyright 2007-2009 Medsea Business Solutions S.L.
*
* 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 eu.medsea.mimeutil.handler;
import eu.medsea.mimeutil.TextMimeType;
/**
* This interface is to be implemented by all TextMmeDetector(s)
* that are registered with the TextMimeDetector
*
* A scenario in which you would want to use this feature is when
* handling text files that are ultimately XML type files.
*
*
* These handlers are given a chance to influence the returned
* MimeType present in the Collection returned from the TextMimeDetector
* that is pre-registered with mime-util. Each TextMimeHandler will
* be called in the order they are registered. If the handle(...) method
* returns true, no more handlers will be called but if handle(...) returns false
* the next handler in the chain will be called and given a chance to change the
* information contained in the passed in TextMimeType such as the mediaType, subType
* and encoding.
*
*
* As these operate in a chain like fashion you can create generic handlers for say
* XML files that checks the content for the presence of the xml declaration and set
* the media and sub types of the MimeType to text/xml instead of the default text/plain.
* You can also change the encoding from the guessed encoding to the encoding defined
* in the XML file. The next handler could be configured to only execute it's logic
* if the sub type of the TextMimeType is or contains xml. This handler could then look to see if
* the content is actually and SVG file and change the media type to application, the sub type to svg+xml
* and return true from the handle method so that no more handlers in the chain are called because
* we now know we have the correct information.
*
*
* For some VERY basic implementations of TextMimeHandler(s) using string functions see the unit tests for
* the TextMimeDetector. For your implementations you will probably want to use regular expressions
* to determine content or even to decide if this handler is interested in the content.
*
*
* This is one area that you can contribute back to the community. If you have a first class TexMimeHandler
* implementation for a specific type of text file content then please consider donating it back to
* the project and we will release this in a future contributed library. You could even sell these as
* commercial add ons if it's the bees knees for a specific, hard to detect, type of text content.
*
* @author Steven McArdle
*
*/
public interface TextMimeHandler {
/**
* All TextMimeHandler(s) will have this method that has a chance
* to re-handle what the TextMimeDetector has decided
* @param mimeType what the current TextMimeType looks like i.e. it's
* current MimeType and encoding
* @param content is the actual text you can use to better determine what this text really is
* @return if true is returned then no more registered TextMimeHandler(s) will fire after this.
* false means that the next registered TextMimeHandler in the list gets a chance to also change
* the MimeType and encoding.
*/
public boolean handle(final TextMimeType mimeType, final String content);
}