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Tools to assist in the reading of configuration/preferences files in
various formats
/*
* 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;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.configuration2.convert.ListDelimiterHandler;
import org.apache.commons.configuration2.ex.ConfigurationException;
import org.apache.commons.configuration2.ex.ConfigurationRuntimeException;
import org.apache.commons.configuration2.tree.ImmutableNode;
import org.apache.commons.configuration2.tree.InMemoryNodeModel;
import org.apache.commons.configuration2.tree.InMemoryNodeModelSupport;
import org.apache.commons.configuration2.tree.NodeHandler;
import org.apache.commons.configuration2.tree.NodeHandlerDecorator;
import org.apache.commons.configuration2.tree.NodeSelector;
import org.apache.commons.configuration2.tree.TrackedNodeModel;
/**
*
* A specialized hierarchical configuration implementation for parsing ini
* files.
*
*
* An initialization or ini file is a configuration file typically found on
* Microsoft's Windows operating system and contains data for Windows based
* applications.
*
*
* Although popularized by Windows, ini files can be used on any system or
* platform due to the fact that they are merely text files that can easily be
* parsed and modified by both humans and computers.
*
*
* A typical ini file could look something like:
*
*
* [section1]
* ; this is a comment!
* var1 = foo
* var2 = bar
*
* [section2]
* var1 = doo
*
*
* The format of ini files is fairly straight forward and is composed of three
* components:
*
* - Sections: Ini files are split into sections, each section starting
* with a section declaration. A section declaration starts with a '[' and ends
* with a ']'. Sections occur on one line only.
* - Parameters: Items in a section are known as parameters. Parameters
* have a typical {@code key = value} format.
* - Comments: Lines starting with a ';' are assumed to be comments.
*
*
* There are various implementations of the ini file format by various vendors
* which has caused a number of differences to appear. As far as possible this
* configuration tries to be lenient and support most of the differences.
*
*
* Some of the differences supported are as follows:
*
*
* - Comments: The '#' character is also accepted as a comment
* signifier.
* - Key value separator: The ':' character is also accepted in place of
* '=' to separate keys and values in parameters, for example
* {@code var1 : foo}.
* - Duplicate sections: Typically duplicate sections are not allowed,
* this configuration does however support this feature. In the event of a duplicate
* section, the two section's values are merged so that there is only a single
* section. Note: This also affects the internal data of the
* configuration. If it is saved, only a single section is written!
* - Duplicate parameters: Typically duplicate parameters are only
* allowed if they are in two different sections, thus they are local to
* sections; this configuration simply merges duplicates; if a section has a
* duplicate parameter the values are then added to the key as a list.
*
*
* Global parameters are also allowed; any parameters declared before a section
* is declared are added to a global section. It is important to note that this
* global section does not have a name.
*
*
* In all instances, a parameter's key is prepended with its section name and a
* '.' (period). Thus a parameter named "var1" in "section1" will have the key
* {@code section1.var1} in this configuration. (This is the default
* behavior. Because this is a hierarchical configuration you can change this by
* setting a different {@link org.apache.commons.configuration2.tree.ExpressionEngine}.)
*
* Implementation Details:
Consider the following ini file:
*
* default = ok
*
* [section1]
* var1 = foo
* var2 = doodle
*
* [section2]
* ; a comment
* var1 = baz
* var2 = shoodle
* bad =
* = worse
*
* [section3]
* # another comment
* var1 : foo
* var2 : bar
* var5 : test1
*
* [section3]
* var3 = foo
* var4 = bar
* var5 = test2
*
* [sectionSeparators]
* passwd : abc=def
* a:b = "value"
*
*
* This ini file will be parsed without error. Note:
*
* - The parameter named "default" is added to the global section, it's value
* is accessed simply using {@code getProperty("default")}.
* - Section 1's parameters can be accessed using
* {@code getProperty("section1.var1")}.
* - The parameter named "bad" simply adds the parameter with an empty value.
* - The empty key with value "= worse" is added using a key consisting of a
* single space character. This key is still added to section 2 and the value
* can be accessed using {@code getProperty("section2. ")}, notice the
* period '.' and the space following the section name.
* - Section three uses both '=' and ':' to separate keys and values.
* - Section 3 has a duplicate key named "var5". The value for this key is
* [test1, test2], and is represented as a List.
* - The section called sectionSeparators demonstrates how the
* configuration deals with multiple occurrences of separator characters. Per
* default the first separator character in a line is detected and used to
* split the key from the value. Therefore the first property definition in this
* section has the key {@code passwd} and the value {@code abc=def}.
* This default behavior can be changed by using quotes. If there is a separator
* character before the first quote character (ignoring whitespace), this
* character is used as separator. Thus the second property definition in the
* section has the key {@code a:b} and the value {@code value}.
*
*
* Internally, this configuration maps the content of the represented ini file
* to its node structure in the following way:
*
* - Sections are represented by direct child nodes of the root node.
* - For the content of a section, corresponding nodes are created as children
* of the section node.
*
*
* This explains how the keys for the properties can be constructed. You can
* also use other methods of {@link HierarchicalConfiguration} for querying or
* manipulating the hierarchy of configuration nodes, for instance the
* {@code configurationAt()} method for obtaining the data of a specific
* section. However, be careful that the storage scheme described above is not
* violated (e.g. by adding multiple levels of nodes or inserting duplicate
* section nodes). Otherwise, the special methods for ini configurations may not
* work correctly!
*
*
* The set of sections in this configuration can be retrieved using the
* {@code getSections()} method. For obtaining a
* {@code SubnodeConfiguration} with the content of a specific section the
* {@code getSection()} method can be used.
*
*
* Like other {@code Configuration} implementations, this class uses a
* {@code Synchronizer} object to control concurrent access. By choosing a
* suitable implementation of the {@code Synchronizer} interface, an instance
* can be made thread-safe or not. Note that access to most of the properties
* typically set through a builder is not protected by the {@code Synchronizer}.
* The intended usage is that these properties are set once at construction
* time through the builder and after that remain constant. If you wish to
* change such properties during life time of an instance, you have to use
* the {@code lock()} and {@code unlock()} methods manually to ensure that
* other threads see your changes.
*
*
* As this class extends {@link AbstractConfiguration}, all basic features
* like variable interpolation, list handling, or data type conversions are
* available as well. This is described in the chapter
*
* Basic features and AbstractConfiguration of the user's guide.
*
*
* @author Commons
* Configuration team
* @version $Id: INIConfiguration.java 1739471 2016-04-16 15:02:02Z oheger $
* @since 1.6
*/
public class INIConfiguration extends BaseHierarchicalConfiguration implements
FileBasedConfiguration
{
/**
* The characters that signal the start of a comment line.
*/
protected static final String COMMENT_CHARS = "#;";
/**
* The characters used to separate keys from values.
*/
protected static final String SEPARATOR_CHARS = "=:";
/**
* Constant for the line separator.
*/
private static final String LINE_SEPARATOR = System.getProperty("line.separator");
/**
* The characters used for quoting values.
*/
private static final String QUOTE_CHARACTERS = "\"'";
/**
* The line continuation character.
*/
private static final String LINE_CONT = "\\";
/**
* Create a new empty INI Configuration.
*/
public INIConfiguration()
{
super();
}
/**
* Creates a new instance of {@code INIConfiguration} with the
* content of the specified {@code HierarchicalConfiguration}.
*
* @param c the configuration to be copied
* @since 2.0
*/
public INIConfiguration(HierarchicalConfiguration c)
{
super(c);
}
/**
* Save the configuration to the specified writer.
*
* @param writer - The writer to save the configuration to.
* @throws ConfigurationException If an error occurs while writing the
* configuration
* @throws IOException if an I/O error occurs
*/
@Override
public void write(Writer writer) throws ConfigurationException, IOException
{
PrintWriter out = new PrintWriter(writer);
boolean first = true;
beginRead(false);
try
{
for (ImmutableNode node : getModel().getNodeHandler().getRootNode()
.getChildren())
{
if (isSectionNode(node))
{
if (!first)
{
out.println();
}
out.print("[");
out.print(node.getNodeName());
out.print("]");
out.println();
for (ImmutableNode child : node.getChildren())
{
writeProperty(out, child.getNodeName(),
child.getValue());
}
}
else
{
writeProperty(out, node.getNodeName(), node.getValue());
}
first = false;
}
out.println();
out.flush();
}
finally
{
endRead();
}
}
/**
* Load the configuration from the given reader. Note that the
* {@code clear()} method is not called so the configuration read in will
* be merged with the current configuration.
*
* @param in the reader to read the configuration from.
* @throws ConfigurationException If an error occurs while reading the
* configuration
* @throws IOException if an I/O error occurs
*/
@Override
public void read(Reader in) throws ConfigurationException, IOException
{
BufferedReader bufferedReader = new BufferedReader(in);
Map sectionBuilders = new LinkedHashMap();
ImmutableNode.Builder rootBuilder = new ImmutableNode.Builder();
createNodeBuilders(bufferedReader, rootBuilder, sectionBuilders);
ImmutableNode rootNode = createNewRootNode(rootBuilder, sectionBuilders);
addNodes(null, rootNode.getChildren());
}
/**
* Creates a new root node from the builders constructed while reading the
* configuration file.
*
* @param rootBuilder the builder for the top-level section
* @param sectionBuilders a map storing the section builders
* @return the root node of the newly created hierarchy
*/
private static ImmutableNode createNewRootNode(
ImmutableNode.Builder rootBuilder,
Map sectionBuilders)
{
for (Map.Entry e : sectionBuilders
.entrySet())
{
rootBuilder.addChild(e.getValue().name(e.getKey()).create());
}
return rootBuilder.create();
}
/**
* Reads the content of an INI file from the passed in reader and creates a
* structure of builders for constructing the {@code ImmutableNode} objects
* representing the data.
*
* @param in the reader
* @param rootBuilder the builder for the top-level section
* @param sectionBuilders a map storing the section builders
* @throws IOException if an I/O error occurs
*/
private void createNodeBuilders(BufferedReader in,
ImmutableNode.Builder rootBuilder,
Map sectionBuilders)
throws IOException
{
ImmutableNode.Builder sectionBuilder = rootBuilder;
String line = in.readLine();
while (line != null)
{
line = line.trim();
if (!isCommentLine(line))
{
if (isSectionLine(line))
{
String section = line.substring(1, line.length() - 1);
sectionBuilder = sectionBuilders.get(section);
if (sectionBuilder == null)
{
sectionBuilder = new ImmutableNode.Builder();
sectionBuilders.put(section, sectionBuilder);
}
}
else
{
String key;
String value = "";
int index = findSeparator(line);
if (index >= 0)
{
key = line.substring(0, index);
value = parseValue(line.substring(index + 1), in);
}
else
{
key = line;
}
key = key.trim();
if (key.length() < 1)
{
// use space for properties with no key
key = " ";
}
createValueNodes(sectionBuilder, key, value);
}
}
line = in.readLine();
}
}
/**
* Creates the node(s) for the given key value-pair. If delimiter parsing is
* enabled, the value string is split if possible, and for each single value
* a node is created. Otherwise only a single node is added to the section.
*
* @param sectionBuilder the section builder for adding new nodes
* @param key the key
* @param value the value string
*/
private void createValueNodes(ImmutableNode.Builder sectionBuilder,
String key, String value)
{
Collection values =
getListDelimiterHandler().split(value, false);
for (String v : values)
{
sectionBuilder.addChild(new ImmutableNode.Builder().name(key)
.value(v).create());
}
}
/**
* Writes data about a property into the given stream.
*
* @param out the output stream
* @param key the key
* @param value the value
*/
private void writeProperty(PrintWriter out, String key, Object value)
{
out.print(key);
out.print(" = ");
out.print(escapeValue(value.toString()));
out.println();
}
/**
* Parse the value to remove the quotes and ignoring the comment. Example:
*
*
* "value" ; comment -> value
*
*
*
* 'value' ; comment -> value
*
* Note that a comment character is only recognized if there is at least one
* whitespace character before it. So it can appear in the property value,
* e.g.:
*
* C:\\Windows;C:\\Windows\\system32
*
*
* @param val the value to be parsed
* @param reader the reader (needed if multiple lines have to be read)
* @throws IOException if an IO error occurs
*/
private static String parseValue(String val, BufferedReader reader) throws IOException
{
StringBuilder propertyValue = new StringBuilder();
boolean lineContinues;
String value = val.trim();
do
{
boolean quoted = value.startsWith("\"") || value.startsWith("'");
boolean stop = false;
boolean escape = false;
char quote = quoted ? value.charAt(0) : 0;
int i = quoted ? 1 : 0;
StringBuilder result = new StringBuilder();
char lastChar = 0;
while (i < value.length() && !stop)
{
char c = value.charAt(i);
if (quoted)
{
if ('\\' == c && !escape)
{
escape = true;
}
else if (!escape && quote == c)
{
stop = true;
}
else if (escape && quote == c)
{
escape = false;
result.append(c);
}
else
{
if (escape)
{
escape = false;
result.append('\\');
}
result.append(c);
}
}
else
{
if (isCommentChar(c) && Character.isWhitespace(lastChar))
{
stop = true;
}
else
{
result.append(c);
}
}
i++;
lastChar = c;
}
String v = result.toString();
if (!quoted)
{
v = v.trim();
lineContinues = lineContinues(v);
if (lineContinues)
{
// remove trailing "\"
v = v.substring(0, v.length() - 1).trim();
}
}
else
{
lineContinues = lineContinues(value, i);
}
propertyValue.append(v);
if (lineContinues)
{
propertyValue.append(LINE_SEPARATOR);
value = reader.readLine();
}
} while (lineContinues && value != null);
return propertyValue.toString();
}
/**
* Tests whether the specified string contains a line continuation marker.
*
* @param line the string to check
* @return a flag whether this line continues
*/
private static boolean lineContinues(String line)
{
String s = line.trim();
return s.equals(LINE_CONT)
|| (s.length() > 2 && s.endsWith(LINE_CONT) && Character
.isWhitespace(s.charAt(s.length() - 2)));
}
/**
* Tests whether the specified string contains a line continuation marker
* after the specified position. This method parses the string to remove a
* comment that might be present. Then it checks whether a line continuation
* marker can be found at the end.
*
* @param line the line to check
* @param pos the start position
* @return a flag whether this line continues
*/
private static boolean lineContinues(String line, int pos)
{
String s;
if (pos >= line.length())
{
s = line;
}
else
{
int end = pos;
while (end < line.length() && !isCommentChar(line.charAt(end)))
{
end++;
}
s = line.substring(pos, end);
}
return lineContinues(s);
}
/**
* Tests whether the specified character is a comment character.
*
* @param c the character
* @return a flag whether this character starts a comment
*/
private static boolean isCommentChar(char c)
{
return COMMENT_CHARS.indexOf(c) >= 0;
}
/**
* Tries to find the index of the separator character in the given string.
* This method checks for the presence of separator characters in the given
* string. If multiple characters are found, the first one is assumed to be
* the correct separator. If there are quoting characters, they are taken
* into account, too.
*
* @param line the line to be checked
* @return the index of the separator character or -1 if none is found
*/
private static int findSeparator(String line)
{
int index =
findSeparatorBeforeQuote(line,
findFirstOccurrence(line, QUOTE_CHARACTERS));
if (index < 0)
{
index = findFirstOccurrence(line, SEPARATOR_CHARS);
}
return index;
}
/**
* Checks for the occurrence of the specified separators in the given line.
* The index of the first separator is returned.
*
* @param line the line to be investigated
* @param separators a string with the separator characters to look for
* @return the lowest index of a separator character or -1 if no separator
* is found
*/
private static int findFirstOccurrence(String line, String separators)
{
int index = -1;
for (int i = 0; i < separators.length(); i++)
{
char sep = separators.charAt(i);
int pos = line.indexOf(sep);
if (pos >= 0)
{
if (index < 0 || pos < index)
{
index = pos;
}
}
}
return index;
}
/**
* Searches for a separator character directly before a quoting character.
* If the first non-whitespace character before a quote character is a
* separator, it is considered the "real" separator in this line - even if
* there are other separators before.
*
* @param line the line to be investigated
* @param quoteIndex the index of the quote character
* @return the index of the separator before the quote or < 0 if there is
* none
*/
private static int findSeparatorBeforeQuote(String line, int quoteIndex)
{
int index = quoteIndex - 1;
while (index >= 0 && Character.isWhitespace(line.charAt(index)))
{
index--;
}
if (index >= 0 && SEPARATOR_CHARS.indexOf(line.charAt(index)) < 0)
{
index = -1;
}
return index;
}
/**
* Escapes the given property value before it is written. This method add
* quotes around the specified value if it contains a comment character and
* handles list delimiter characters.
*
* @param value the string to be escaped
*/
private String escapeValue(String value)
{
return String.valueOf(getListDelimiterHandler().escape(
escapeComments(value), ListDelimiterHandler.NOOP_TRANSFORMER));
}
/**
* Escapes comment characters in the given value.
*
* @param value the value to be escaped
* @return the value with comment characters escaped
*/
private static String escapeComments(String value)
{
boolean quoted = false;
for (int i = 0; i < COMMENT_CHARS.length() && !quoted; i++)
{
char c = COMMENT_CHARS.charAt(i);
if (value.indexOf(c) != -1)
{
quoted = true;
}
}
if (quoted)
{
return '"' + value.replaceAll("\"", "\\\\\\\"") + '"';
}
else
{
return value;
}
}
/**
* Determine if the given line is a comment line.
*
* @param line The line to check.
* @return true if the line is empty or starts with one of the comment
* characters
*/
protected boolean isCommentLine(String line)
{
if (line == null)
{
return false;
}
// blank lines are also treated as comment lines
return line.length() < 1 || COMMENT_CHARS.indexOf(line.charAt(0)) >= 0;
}
/**
* Determine if the given line is a section.
*
* @param line The line to check.
* @return true if the line contains a section
*/
protected boolean isSectionLine(String line)
{
if (line == null)
{
return false;
}
return line.startsWith("[") && line.endsWith("]");
}
/**
* Return a set containing the sections in this ini configuration. Note that
* changes to this set do not affect the configuration.
*
* @return a set containing the sections.
*/
public Set getSections()
{
Set sections = new LinkedHashSet();
boolean globalSection = false;
boolean inSection = false;
beginRead(false);
try
{
for (ImmutableNode node : getModel().getNodeHandler().getRootNode()
.getChildren())
{
if (isSectionNode(node))
{
inSection = true;
sections.add(node.getNodeName());
}
else
{
if (!inSection && !globalSection)
{
globalSection = true;
sections.add(null);
}
}
}
}
finally
{
endRead();
}
return sections;
}
/**
* Returns a configuration with the content of the specified section. This
* provides an easy way of working with a single section only. The way this
* configuration is structured internally, this method is very similar to
* calling {@link HierarchicalConfiguration#configurationAt(String)} with
* the name of the section in question. There are the following differences
* however:
*
* - This method never throws an exception. If the section does not exist,
* it is created now. The configuration returned in this case is empty.
* - If section is contained multiple times in the configuration, the
* configuration returned by this method is initialized with the first
* occurrence of the section. (This can only happen if
* {@code addProperty()} has been used in a way that does not conform
* to the storage scheme used by {@code INIConfiguration}.
* If used correctly, there will not be duplicate sections.)
* - There is special support for the global section: Passing in
* null as section name returns a configuration with the content of
* the global section (which may also be empty).
*
*
* @param name the name of the section in question; null represents
* the global section
* @return a configuration containing only the properties of the specified
* section
*/
public SubnodeConfiguration getSection(String name)
{
if (name == null)
{
return getGlobalSection();
}
else
{
try
{
return (SubnodeConfiguration) configurationAt(name, true);
}
catch (ConfigurationRuntimeException iex)
{
// the passed in key does not map to exactly one node
// obtain the node for the section, create it on demand
InMemoryNodeModel parentModel = getSubConfigurationParentModel();
NodeSelector selector = parentModel.trackChildNodeWithCreation(null, name, this);
return createSubConfigurationForTrackedNode(selector, this);
}
}
}
/**
* Creates a sub configuration for the global section of the represented INI
* configuration.
*
* @return the sub configuration for the global section
*/
private SubnodeConfiguration getGlobalSection()
{
InMemoryNodeModel parentModel = getSubConfigurationParentModel();
NodeSelector selector = new NodeSelector(null); // selects parent
parentModel.trackNode(selector, this);
GlobalSectionNodeModel model =
new GlobalSectionNodeModel(this, selector);
SubnodeConfiguration sub = new SubnodeConfiguration(this, model);
initSubConfigurationForThisParent(sub);
return sub;
}
/**
* Checks whether the specified configuration node represents a section.
*
* @param node the node in question
* @return a flag whether this node represents a section
*/
private static boolean isSectionNode(ImmutableNode node)
{
return !node.getChildren().isEmpty();
}
/**
* A specialized node model implementation for the sub configuration
* representing the global section of the INI file. This is a regular
* {@code TrackedNodeModel} with one exception: The {@code NodeHandler} used
* by this model applies a filter on the children of the root node so that
* only nodes are visible that are no sub sections.
*/
private static class GlobalSectionNodeModel extends TrackedNodeModel
{
/**
* Creates a new instance of {@code GlobalSectionNodeModel} and
* initializes it with the given underlying model.
*
* @param modelSupport the underlying {@code InMemoryNodeModel}
* @param selector the {@code NodeSelector}
*/
public GlobalSectionNodeModel(InMemoryNodeModelSupport modelSupport,
NodeSelector selector)
{
super(modelSupport, selector, true);
}
@Override
public NodeHandler getNodeHandler()
{
return new NodeHandlerDecorator()
{
@Override
public List getChildren(ImmutableNode node)
{
List children = super.getChildren(node);
return filterChildrenOfGlobalSection(node, children);
}
@Override
public List getChildren(ImmutableNode node,
String name)
{
List children =
super.getChildren(node, name);
return filterChildrenOfGlobalSection(node, children);
}
@Override
public int getChildrenCount(ImmutableNode node, String name)
{
List children =
(name != null) ? super.getChildren(node, name)
: super.getChildren(node);
return filterChildrenOfGlobalSection(node, children).size();
}
@Override
public ImmutableNode getChild(ImmutableNode node, int index)
{
List children = super.getChildren(node);
return filterChildrenOfGlobalSection(node, children).get(
index);
}
@Override
public int indexOfChild(ImmutableNode parent,
ImmutableNode child)
{
List children = super.getChildren(parent);
return filterChildrenOfGlobalSection(parent, children)
.indexOf(child);
}
@Override
protected NodeHandler getDecoratedNodeHandler()
{
return GlobalSectionNodeModel.super.getNodeHandler();
}
/**
* Filters the child nodes of the global section. This method
* checks whether the passed in node is the root node of the
* configuration. If so, from the list of children all nodes are
* filtered which are section nodes.
*
* @param node the node in question
* @param children the children of this node
* @return a list with the filtered children
*/
private List filterChildrenOfGlobalSection(
ImmutableNode node, List children)
{
List filteredList;
if (node == getRootNode())
{
filteredList =
new ArrayList(children.size());
for (ImmutableNode child : children)
{
if (!isSectionNode(child))
{
filteredList.add(child);
}
}
}
else
{
filteredList = children;
}
return filteredList;
}
};
}
}
}