org.simpleframework.xml.util
Class Resolver<M extends Match>

java.lang.Object
  extended by java.util.AbstractCollection<E>
      extended by java.util.AbstractSet<M>
          extended by org.simpleframework.xml.util.Resolver<M>
All Implemented Interfaces:
Iterable<M>, Collection<M>, Set<M>

public class Resolver<M extends Match>
extends AbstractSet<M>

This is used to store Match objects, which can then be retrieved using a string by comparing that string to the pattern of the Match objects. Patterns consist of characters with either the '*' or '?' characters as wild characters. The '*' character is completely wild meaning that is will match nothing or a long sequence of characters. The '?' character matches a single character.

If the '?' character immediately follows the '*' character then the match is made as any sequence of characters up to the first match of the next character. For example "/*?/index.jsp" will match all files preceeded by only a single path. So "/pub/index.jsp" will match, however "/pub/bin/index.jsp" will not, as it has two paths. So, in effect the '*?' sequence will match anything or nothing up to the first occurence of the next character in the pattern.

A design goal of the Resolver was to make it capable of high performance. In order to achieve a high performance the Resolver can cache the resolutions it makes so that if the same text is given to the Resolver.resolve method a cached result can be retrived quickly which will decrease the length of time and work required to perform the match.

The semantics of the resolver are such that the last pattern added with a wild string is the first one checked for a match. This means that if a sequence of insertions like add(x) followed by add(y) is made, then a resolve(z) will result in a comparison to y first and then x, if z matches y then it is given as the result and if z does not match y and matches x then x is returned, remember if z matches both x and y then y will be the result due to the fact that is was the last pattern added.

Author:
Niall Gallagher

Field Summary
protected  org.simpleframework.xml.util.Resolver.Cache cache
          Caches the text resolutions made to reduce the work required.
protected  org.simpleframework.xml.util.Resolver.Stack stack
          Stores the matches added to the resolver in resolution order.
 
Constructor Summary
Resolver()
          The default constructor will create a Resolver without a large cache size.
 
Method Summary
 boolean add(M match)
          This inserts the Match implementation into the set so that it can be used for resolutions.
 void clear()
          This is used to clear all matches from the set.
 Iterator<M> iterator()
          This returns an Iterator that iterates over the matches in insertion order.
 boolean remove(M match)
          This is used to remove the Match implementation from the resolver.
 M resolve(String text)
          This will search the patterns in this Resolver to see if there is a pattern in it that matches the string given.
 List<M> resolveAll(String text)
          This will search the patterns in this Resolver to see if there is a pattern in it that matches the string given.
 int size()
          Returns the number of matches that have been inserted into the Resolver.
 
Methods inherited from class java.util.AbstractSet
equals, hashCode, removeAll
 
Methods inherited from class java.util.AbstractCollection
addAll, contains, containsAll, isEmpty, remove, retainAll, toArray, toArray, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Set
addAll, contains, containsAll, isEmpty, remove, retainAll, toArray, toArray
 

Field Detail

cache

protected final org.simpleframework.xml.util.Resolver.Cache cache
Caches the text resolutions made to reduce the work required.


stack

protected final org.simpleframework.xml.util.Resolver.Stack stack
Stores the matches added to the resolver in resolution order.

Constructor Detail

Resolver

public Resolver()
The default constructor will create a Resolver without a large cache size. This is intended for use when the requests for resolve tend to use strings that are reasonably similar. If the strings issued to this instance are dramatically different then the cache tends to be an overhead rather than a bonus.

Method Detail

resolve

public M resolve(String text)
This will search the patterns in this Resolver to see if there is a pattern in it that matches the string given. This will search the patterns from the last entered pattern to the first entered. So that the last entered patterns are the most searched patterns and will resolve it first if it matches.

Parameters:
text - this is the string that is to be matched by this
Returns:
this will return the first match within the resolver

resolveAll

public List<M> resolveAll(String text)
This will search the patterns in this Resolver to see if there is a pattern in it that matches the string given. This will search the patterns from the last entered pattern to the first entered. So that the last entered patterns are the most searched patterns and will resolve it first if it matches.

Parameters:
text - this is the string that is to be matched by this
Returns:
this will return all of the matches within the resolver

add

public boolean add(M match)
This inserts the Match implementation into the set so that it can be used for resolutions. The last added match is the first resolved. Because this changes the state of the resolver this clears the cache as it may affect resolutions.

Specified by:
add in interface Collection<M extends Match>
Specified by:
add in interface Set<M extends Match>
Overrides:
add in class AbstractCollection<M extends Match>
Parameters:
match - this is the match that is to be inserted to this
Returns:
returns true if the addition succeeded, always true

iterator

public Iterator<M> iterator()
This returns an Iterator that iterates over the matches in insertion order. So the first match added is the first retrieved from the Iterator. This order is used to ensure that resolver can be serialized properly.

Specified by:
iterator in interface Iterable<M extends Match>
Specified by:
iterator in interface Collection<M extends Match>
Specified by:
iterator in interface Set<M extends Match>
Specified by:
iterator in class AbstractCollection<M extends Match>
Returns:
returns an iterator for the sequence of insertion

remove

public boolean remove(M match)
This is used to remove the Match implementation from the resolver. This clears the cache as the removal of a match may affect the resoultions existing in the cache. The equals method of the match must be implemented.

Parameters:
match - this is the match that is to be removed
Returns:
true of the removal of the match was successful

size

public int size()
Returns the number of matches that have been inserted into the Resolver. Although this is a set, it does not mean that matches cannot used the same pattern string.

Specified by:
size in interface Collection<M extends Match>
Specified by:
size in interface Set<M extends Match>
Specified by:
size in class AbstractCollection<M extends Match>
Returns:
this returns the number of matches within the set

clear

public void clear()
This is used to clear all matches from the set. This ensures that the resolver contains no matches and that the resolution cache is cleared. This is used to that the set can be reused and have new pattern matches inserted into it for resolution.

Specified by:
clear in interface Collection<M extends Match>
Specified by:
clear in interface Set<M extends Match>
Overrides:
clear in class AbstractCollection<M extends Match>