org.xwiki.properties.converter.collection.AbstractCollectionConverter Maven / Gradle / Ivy
/*
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.xwiki.properties.converter.collection;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.io.StringReader;
import java.lang.reflect.Array;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import javax.inject.Inject;
import org.apache.commons.lang3.StringUtils;
import org.xwiki.component.util.ReflectionUtils;
import org.xwiki.properties.ConverterManager;
import org.xwiki.properties.converter.AbstractConverter;
import org.xwiki.properties.converter.ConversionException;
/**
* Base class for all {@link java.util.Collection} converters.
*
* @param the type in which the provided value has to be converted
* @version $Id: 9cdfbdeaeb87e5ff10bdee66bd0a3931c664fa69 $
* @since 5.2M1
*/
public abstract class AbstractCollectionConverter extends AbstractConverter
{
/**
* Quote char.
*/
protected static final char QUOTECHAR = '"';
/**
* Quote string.
*/
protected static final String QUOTESTRING = "\"";
/**
* Used to convert collection elements.
*/
@Inject
private ConverterManager converterManager;
/**
* @see #setDelimiters(String)
*/
private String delimiters = ", ";
/**
* @return the converter manager.
*/
public ConverterManager getConverterManager()
{
return this.converterManager;
}
/**
* Set the delimiter to be used for parsing a delimited String.
*
* @param delimiter The delimiter [default ", "] since 3.2M3
*/
public void setDelimiters(String delimiter)
{
this.delimiters = delimiter;
}
/**
* @return the delimiters
*/
public String getDelimiters()
{
return this.delimiters;
}
@Override
protected G convertToType(Type targetType, Object value)
{
Type elementType = null;
if (targetType instanceof ParameterizedType) {
elementType = ((ParameterizedType) targetType).getActualTypeArguments()[0];
}
if (value instanceof Iterable) {
return fromIterable(targetType, (Iterable) value, elementType);
} else if (value.getClass().isArray()) {
return fromArray(targetType, value, elementType);
} else {
return parseElements(targetType, value.toString(), elementType);
}
}
/**
* @param the type in which the provided value has to be converted
* @param targetType Data type to which this value should be converted.
* @param values the values to be converted (or not) to the target element type
* @param elementType the generic type
* @return List of parsed elements.
* @throws ConversionException if the syntax of value is not syntactically valid
* @throws NullPointerException if value is null
* @since 7.4.6
* @since 8.4.1
* @since 9.0RC1
*/
protected G fromIterable(Type targetType, Iterable values, Type elementType)
{
T collection = newCollection(targetType);
for (Object value : values) {
collection.add(this.converterManager.convert(elementType, value));
}
return (G) collection;
}
/**
* @param the type in which the provided value has to be converted
* @param targetType Data type to which this value should be converted.
* @param values the values to be converted (or not) to the target element type
* @param elementType the generic type
* @return List of parsed elements.
* @throws ConversionException if the syntax of value is not syntactically valid
* @throws NullPointerException if value is null
* @since 7.4.6
* @since 8.4.1
* @since 9.0RC1
*/
protected G fromArray(Type targetType, Object values, Type elementType)
{
T collection = newCollection(targetType);
for (int i = 0; i < Array.getLength(values); ++i) {
Object value = Array.get(values, i);
collection.add(this.converterManager.convert(elementType, value));
}
return (G) collection;
}
/**
*
* Parse an incoming String of the form similar to an array initializer in the Java language into a
* List individual Strings for each element, according to the following rules.
*
*
* - The string is expected to be a comma-separated list of values.
* - The string may optionally have matching '{' and '}' delimiters around the list.
* - Whitespace before and after each element is stripped.
* - Elements in the list may be delimited by single or double quotes. Within a quoted elements, the normal Java
* escape sequences are valid.
*
*
* @param the type in which the provided value has to be converted
* @param targetType Data type to which this value should be converted.
* @param value String value to be parsed
* @param elementType the generic type
* @return List of parsed elements.
* @throws ConversionException if the syntax of value is not syntactically valid
* @throws NullPointerException if value is null
*/
protected G parseElements(Type targetType, String value, Type elementType)
{
String cleanedValue = cleanValue(value);
try {
// Set up a StreamTokenizer on the characters in this String
StreamTokenizer st = createStreamTokenizer(cleanedValue);
// Split comma-delimited tokens into a List
T collection = newCollection(targetType);
while (true) {
int ttype = st.nextToken();
if (ttype == StreamTokenizer.TT_WORD || ttype > 0) {
if (st.sval != null) {
Object objValue = st.sval;
if (elementType != null && elementType != String.class) {
objValue = this.converterManager.convert(elementType, objValue);
}
collection.add(objValue);
}
} else if (ttype == StreamTokenizer.TT_EOF) {
break;
} else {
throw new ConversionException("Encountered token of type " + ttype + " parsing elements.");
}
}
// Return the completed list
return (G) collection;
} catch (IOException e) {
throw new ConversionException("Error converting from String: " + e.getMessage(), e);
}
}
/**
* @param the type of the collection to create
* @param targetType the type of the collection to create
* @return the modifiable {@link Collection} to fill
*/
protected T newCollection(Type targetType)
{
Class targetClass = ReflectionUtils.getTypeClass(targetType);
if (targetClass.isAssignableFrom(ArrayList.class)) {
return (G) new ArrayList();
} else {
try {
return targetClass.newInstance();
} catch (Exception e) {
throw new ConversionException("Failed to create new instance of target type [" + targetType + "]", e);
}
}
}
/**
* @param value the string to cleanup
* @return the clean version of the string
*/
private String cleanValue(String value)
{
// Trim any matching '{' and '}' delimiters
String cleanedValue = value.trim();
if (cleanedValue.startsWith("{") && cleanedValue.endsWith("}")) {
cleanedValue = cleanedValue.substring(1, cleanedValue.length() - 1);
}
return cleanedValue;
}
/**
* Create and initialize a {@link StreamTokenizer} to parse the value.
*
* @param value the string to parse
* @return the {@link StreamTokenizer} used to parse the string
*/
protected StreamTokenizer createStreamTokenizer(String value)
{
// Set up a StreamTokenizer on the characters in this String
StreamTokenizer st = new StreamTokenizer(new StringReader(value));
// Everything is word
st.ordinaryChars(0, 255);
st.wordChars(0, 255);
// Except quote chars
st.quoteChar('"');
st.quoteChar('\'');
// And delimiters
for (char c : getDelimiters().toCharArray()) {
st.whitespaceChars(c, c);
}
return st;
}
@Override
protected String convertToString(T value)
{
StringBuilder sb = new StringBuilder();
for (Object element : value) {
if (sb.length() > 0) {
sb.append(getDelimiters());
}
String elementString = getConverterManager().convert(String.class, element);
if (elementString != null) {
boolean containsDelimiter = StringUtils.containsAny(elementString, getDelimiters());
if (containsDelimiter) {
sb.append(QUOTESTRING);
}
sb.append(elementString.replace("\\", "\\\\").replace(QUOTESTRING, "\\\"").replace("'", "\\'"));
if (containsDelimiter) {
sb.append(QUOTESTRING);
}
}
}
return sb.toString();
}
}