src/main/java/org/apache/commons/configuration2/convert/LegacyListDelimiterHandler.java - commons-configuration - Git at Google

 /*
  * 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.
  */
 package org.apache.commons.configuration2.convert;

 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;

 import org.apache.commons.lang3.StringUtils;

 /**
  * <p>
  * A specialized implementation of {@code ListDelimiterHandler} which simulates
  * the list delimiter handling as it was used by {@code PropertiesConfiguration}
  * in Commons Configuration 1.x.
  * </p>
  * <p>
  * This class mainly exists for compatibility reasons. It is intended to be used
  * by applications which have to deal with properties files created by an older
  * version of this library.
  * </p>
  * <p>
  * In the 1.x series of Commons Configuration list handling was not fully
  * consistent. The escaping of property values was done in a different way if
  * they contained a list delimiter or not. From version 2.0 on, escaping is more
  * stringent which might cause slightly different results when parsing
  * properties files created by or for Configuration 1.x. If you encounter such
  * problems, you can switch to this {@code ListDelimiterHandler} implementation
  * rather than the default one. In other cases, this class should not be used!
  * </p>
  * <p>
  * Implementation note: An instance of this class can safely be shared between
  * multiple {@code Configuration} instances.
  * </p>
  *
  * @version $Id$
  * @since 2.0
  */
 public class LegacyListDelimiterHandler extends AbstractListDelimiterHandler
 {
     /** Constant for the escaping character. */
     private static final String ESCAPE = "\\";

     /** Constant for the escaped escaping character. */
     private static final String DOUBLE_ESC = ESCAPE + ESCAPE;

     /** Constant for a duplicated sequence of escaping characters. */
     private static final String QUAD_ESC = DOUBLE_ESC + DOUBLE_ESC;

     /** The list delimiter character. */
     private final char delimiter;

     /**
      * Creates a new instance of {@code LegacyListDelimiterHandler} and sets the
      * list delimiter character.
      *
      * @param listDelimiter the list delimiter character
      */
     public LegacyListDelimiterHandler(char listDelimiter)
     {
         delimiter = listDelimiter;
     }

     /**
      * Returns the list delimiter character.
      *
      * @return the list delimiter character
      */
     public char getDelimiter()
     {
         return delimiter;
     }

     /**
      * {@inheritDoc} This implementation performs delimiter escaping for a
      * single value (which is not part of a list).
      */
     @Override
     public Object escape(Object value, ValueTransformer transformer)
     {
         return escapeValue(value, false, transformer);
     }

     /**
      * {@inheritDoc} This implementation performs a special encoding of
      * backslashes at the end of a string so that they are not interpreted as
      * escape character for a following list delimiter.
      */
     @Override
     public Object escapeList(List<?> values, ValueTransformer transformer)
     {
         if (!values.isEmpty())
         {
             Iterator<?> it = values.iterator();
             String lastValue = escapeValue(it.next(), true, transformer);
             StringBuilder buf = new StringBuilder(lastValue);
             while (it.hasNext())
             {
                 // if the last value ended with an escape character, it has
                 // to be escaped itself; otherwise the list delimiter will
                 // be escaped
                 if (lastValue.endsWith(ESCAPE)
                         && (countTrailingBS(lastValue) / 2) % 2 != 0)
                 {
                     buf.append(ESCAPE).append(ESCAPE);
                 }
                 buf.append(getDelimiter());
                 lastValue = escapeValue(it.next(), true, transformer);
                 buf.append(lastValue);
             }
             return buf.toString();
         }
         else
         {
             return null;
         }
     }

     /**
      * {@inheritDoc} This implementation simulates the old splitting algorithm.
      * The string is split at the delimiter character if it is not escaped. If
      * the delimiter character is not found, the input is returned unchanged.
      */
     @Override
     protected Collection<String> splitString(String s, boolean trim)
     {
         if (s.indexOf(getDelimiter()) < 0)
         {
             return Collections.singleton(s);
         }

         List<String> list = new ArrayList<String>();

         StringBuilder token = new StringBuilder();
         int begin = 0;
         boolean inEscape = false;
         char esc = ESCAPE.charAt(0);

         while (begin < s.length())
         {
             char c = s.charAt(begin);
             if (inEscape)
             {
                 // last character was the escape marker
                 // can current character be escaped?
                 if (c != getDelimiter() && c != esc)
                 {
                     // no, also add escape character
                     token.append(esc);
                 }
                 token.append(c);
                 inEscape = false;
             }

             else
             {
                 if (c == getDelimiter())
                 {
                     // found a list delimiter -> add token and
                     // resetDefaultFileSystem buffer
                     String t = token.toString();
                     if (trim)
                     {
                         t = t.trim();
                     }
                     list.add(t);
                     token = new StringBuilder();
                 }
                 else if (c == esc)
                 {
                     // eventually escape next character
                     inEscape = true;
                 }
                 else
                 {
                     token.append(c);
                 }
             }

             begin++;
         }

         // Trailing delimiter?
         if (inEscape)
         {
             token.append(esc);
         }
         // Add last token
         String t = token.toString();
         if (trim)
         {
             t = t.trim();
         }
         list.add(t);

         return list;
     }

     /**
      * {@inheritDoc} This is just a dummy implementation. It is never called.
      */
     @Override
     protected String escapeString(String s)
     {
         return null;
     }

     /**
      * Performs the escaping of backslashes in the specified properties value.
      * Because a double backslash is used to escape the escape character of a
      * list delimiter, double backslashes also have to be escaped if the
      * property is part of a (single line) list. In addition, because the output
      * is written into a properties file, each occurrence of a backslash again
      * has to be doubled. This method is called by {@code escapeValue()}.
      *
      * @param value the value to be escaped
      * @param inList a flag whether the value is part of a list
      * @return the value with escaped backslashes as string
      */
     protected String escapeBackslashs(Object value, boolean inList)
     {
         String strValue = String.valueOf(value);

         if (inList && strValue.indexOf(DOUBLE_ESC) >= 0)
         {
             strValue = StringUtils.replace(strValue, DOUBLE_ESC, QUAD_ESC);
         }

         return strValue;
     }

     /**
      * Escapes the given property value. This method is called on saving the
      * configuration for each property value. It ensures a correct handling of
      * backslash characters and also takes care that list delimiter characters
      * in the value are escaped.
      *
      * @param value the property value
      * @param inList a flag whether the value is part of a list
      * @param transformer the {@code ValueTransformer}
      * @return the escaped property value
      */
     protected String escapeValue(Object value, boolean inList,
             ValueTransformer transformer)
     {
         String escapedValue =
                 String.valueOf(transformer.transformValue(escapeBackslashs(
                         value, inList)));
         if (getDelimiter() != 0)
         {
             escapedValue =
                     StringUtils.replace(escapedValue,
                             String.valueOf(getDelimiter()), ESCAPE
                                     + getDelimiter());
         }
         return escapedValue;
     }

     /**
      * Returns the number of trailing backslashes. This is sometimes needed for
      * the correct handling of escape characters.
      *
      * @param line the string to investigate
      * @return the number of trailing backslashes
      */
     private static int countTrailingBS(String line)
     {
         int bsCount = 0;
         for (int idx = line.length() - 1; idx >= 0 && line.charAt(idx) == '\\'; idx--)
         {
             bsCount++;
         }

         return bsCount;
     }
 }
	/*
	* 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.
	*/
	package org.apache.commons.configuration2.convert;

	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.Iterator;
	import java.util.List;

	import org.apache.commons.lang3.StringUtils;

	/**
	* <p>
	* A specialized implementation of {@code ListDelimiterHandler} which simulates
	* the list delimiter handling as it was used by {@code PropertiesConfiguration}
	* in Commons Configuration 1.x.
	* </p>
	* <p>
	* This class mainly exists for compatibility reasons. It is intended to be used
	* by applications which have to deal with properties files created by an older
	* version of this library.
	* </p>
	* <p>
	* In the 1.x series of Commons Configuration list handling was not fully
	* consistent. The escaping of property values was done in a different way if
	* they contained a list delimiter or not. From version 2.0 on, escaping is more
	* stringent which might cause slightly different results when parsing
	* properties files created by or for Configuration 1.x. If you encounter such
	* problems, you can switch to this {@code ListDelimiterHandler} implementation
	* rather than the default one. In other cases, this class should not be used!
	* </p>
	* <p>
	* Implementation note: An instance of this class can safely be shared between
	* multiple {@code Configuration} instances.
	* </p>
	*
	* @version $Id$
	* @since 2.0
	*/
	public class LegacyListDelimiterHandler extends AbstractListDelimiterHandler
	{
	/** Constant for the escaping character. */
	private static final String ESCAPE = "\\";

	/** Constant for the escaped escaping character. */
	private static final String DOUBLE_ESC = ESCAPE + ESCAPE;

	/** Constant for a duplicated sequence of escaping characters. */
	private static final String QUAD_ESC = DOUBLE_ESC + DOUBLE_ESC;

	/** The list delimiter character. */
	private final char delimiter;

	/**
	* Creates a new instance of {@code LegacyListDelimiterHandler} and sets the
	* list delimiter character.
	*
	* @param listDelimiter the list delimiter character
	*/
	public LegacyListDelimiterHandler(char listDelimiter)
	{
	delimiter = listDelimiter;
	}

	/**
	* Returns the list delimiter character.
	*
	* @return the list delimiter character
	*/
	public char getDelimiter()
	{
	return delimiter;
	}

	/**
	* {@inheritDoc} This implementation performs delimiter escaping for a
	* single value (which is not part of a list).
	*/
	@Override
	public Object escape(Object value, ValueTransformer transformer)
	{
	return escapeValue(value, false, transformer);
	}

	/**
	* {@inheritDoc} This implementation performs a special encoding of
	* backslashes at the end of a string so that they are not interpreted as
	* escape character for a following list delimiter.
	*/
	@Override
	public Object escapeList(List<?> values, ValueTransformer transformer)
	{
	if (!values.isEmpty())
	{
	Iterator<?> it = values.iterator();
	String lastValue = escapeValue(it.next(), true, transformer);
	StringBuilder buf = new StringBuilder(lastValue);
	while (it.hasNext())
	{
	// if the last value ended with an escape character, it has
	// to be escaped itself; otherwise the list delimiter will
	// be escaped
	if (lastValue.endsWith(ESCAPE)
	&& (countTrailingBS(lastValue) / 2) % 2 != 0)
	{
	buf.append(ESCAPE).append(ESCAPE);
	}
	buf.append(getDelimiter());
	lastValue = escapeValue(it.next(), true, transformer);
	buf.append(lastValue);
	}
	return buf.toString();
	}
	else
	{
	return null;
	}
	}

	/**
	* {@inheritDoc} This implementation simulates the old splitting algorithm.
	* The string is split at the delimiter character if it is not escaped. If
	* the delimiter character is not found, the input is returned unchanged.
	*/
	@Override
	protected Collection<String> splitString(String s, boolean trim)
	{
	if (s.indexOf(getDelimiter()) < 0)
	{
	return Collections.singleton(s);
	}

	List<String> list = new ArrayList<String>();

	StringBuilder token = new StringBuilder();
	int begin = 0;
	boolean inEscape = false;
	char esc = ESCAPE.charAt(0);

	while (begin < s.length())
	{
	char c = s.charAt(begin);
	if (inEscape)
	{
	// last character was the escape marker
	// can current character be escaped?
	if (c != getDelimiter() && c != esc)
	{
	// no, also add escape character
	token.append(esc);
	}
	token.append(c);
	inEscape = false;
	}

	else
	{
	if (c == getDelimiter())
	{
	// found a list delimiter -> add token and
	// resetDefaultFileSystem buffer
	String t = token.toString();
	if (trim)
	{
	t = t.trim();
	}
	list.add(t);
	token = new StringBuilder();
	}
	else if (c == esc)
	{
	// eventually escape next character
	inEscape = true;
	}
	else
	{
	token.append(c);
	}
	}

	begin++;
	}

	// Trailing delimiter?
	if (inEscape)
	{
	token.append(esc);
	}
	// Add last token
	String t = token.toString();
	if (trim)
	{
	t = t.trim();
	}
	list.add(t);

	return list;
	}

	/**
	* {@inheritDoc} This is just a dummy implementation. It is never called.
	*/
	@Override
	protected String escapeString(String s)
	{
	return null;
	}

	/**
	* Performs the escaping of backslashes in the specified properties value.
	* Because a double backslash is used to escape the escape character of a
	* list delimiter, double backslashes also have to be escaped if the
	* property is part of a (single line) list. In addition, because the output
	* is written into a properties file, each occurrence of a backslash again
	* has to be doubled. This method is called by {@code escapeValue()}.
	*
	* @param value the value to be escaped
	* @param inList a flag whether the value is part of a list
	* @return the value with escaped backslashes as string
	*/
	protected String escapeBackslashs(Object value, boolean inList)
	{
	String strValue = String.valueOf(value);

	if (inList && strValue.indexOf(DOUBLE_ESC) >= 0)
	{
	strValue = StringUtils.replace(strValue, DOUBLE_ESC, QUAD_ESC);
	}

	return strValue;
	}

	/**
	* Escapes the given property value. This method is called on saving the
	* configuration for each property value. It ensures a correct handling of
	* backslash characters and also takes care that list delimiter characters
	* in the value are escaped.
	*
	* @param value the property value
	* @param inList a flag whether the value is part of a list
	* @param transformer the {@code ValueTransformer}
	* @return the escaped property value
	*/
	protected String escapeValue(Object value, boolean inList,
	ValueTransformer transformer)
	{
	String escapedValue =
	String.valueOf(transformer.transformValue(escapeBackslashs(
	value, inList)));
	if (getDelimiter() != 0)
	{
	escapedValue =
	StringUtils.replace(escapedValue,
	String.valueOf(getDelimiter()), ESCAPE
	+ getDelimiter());
	}
	return escapedValue;
	}

	/**
	* Returns the number of trailing backslashes. This is sometimes needed for
	* the correct handling of escape characters.
	*
	* @param line the string to investigate
	* @return the number of trailing backslashes
	*/
	private static int countTrailingBS(String line)
	{
	int bsCount = 0;
	for (int idx = line.length() - 1; idx >= 0 && line.charAt(idx) == '\\'; idx--)
	{
	bsCount++;
	}

	return bsCount;
	}
	}