PreferredResources (Apache River v3.0.0 API Documentation (internals))

java.lang.Object
- net.jini.loader.pref.PreferredResources

```
final class PreferredResources
extends Object
```
Internal data structure which holds preference information for a preferred class loader. This utility is used only by the preferred class loader provider and is not intended to be a public API. A preferred resources object is created from an input stream which is formatted according to the Preferred List Syntax which is defined in the specification for net.jini.loader.pref.PreferredClassProvider Preferred resources instances hold preferred list expression data and the preferred state for the resources contained in a given preferred class loader. PreferredResouces is thread safe. Originally from package org.apache.river.loader.pref.internal.

Since:

2.0

Author:

Sun Microsystems, Inc.

Field Summary

Fields
Modifier and Type	Field and Description
`private Map<String,Object>`	`completeNamePrefs`
`private Boolean`	`defaultPreference` default preference setting
`private static String`	`HEADER_MAJOR_VERSION`
`private static String`	`HEADER_MINOR_VERSION`
`private static String`	`HEADER_TITLE` string that starts preference specification headers
`private boolean`	`isEmpty` flag to signal if this preference object is empty
`static int`	`NAME_NO_PREFERENCE` Constant value that indicates that there is no preference value for a given name.
`static int`	`NAME_NOT_PREFERRED` Constant value that indicates that the resource for a given name is known to be not preferred.
`static int`	`NAME_PREFERRED` Constant value that indicates that a given name is preferred.
`static int`	`NAME_PREFERRED_RESOURCE_EXISTS` Constant value that indicates that a given resource is preferred.
`private static String`	`NAME_PREFIX`
`private Map<String,Object>`	`namespacePrefs`
`private Map<String,Object>`	`packagePrefs`
`private static String`	`PREF_PREFIX` preference syntax keywords

Constructor Summary

Constructors
Constructor and Description

PreferredResources(InputStream in)
Create a preference object from a stream of formatted preference syntax.

Constructors
Constructor and Description
`PreferredResources(InputStream in)` Create a preference object from a stream of formatted preference syntax.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`private Integer`	`getClassNameState(String name)` Returns the preference state for a given name (as is done in getNonclassNameState) but also interprets the notation for inner classes as a wild card so that the preference value for a container class propagates to the classes it contains.
`Boolean`	`getDefaultPreference()` Returns the preference setting that will be applied to names which have no explicit preference setting in contained preference settings.
`private Boolean`	`getNamespacePreference(String namespace)` Return a Boolean for the most specific namespace expression which matches `name`. null if the name does not match a namespace preference expression.
`int`	`getNameState(String name, boolean isClass)` Searches the preference maps to determine the preference state of the named resource.
`Boolean`	`getWildcardPreference(String name)` Return the boolean value of the most specific wild card (package and namespace) expression which matches `name`.
`private void`	`mapPut(Map<String,Object> map, String name, Object preference)` Insert a preference expression and value into a given map.
`private String`	`readLineTrimComments(BufferedReader br)` Reads the next line from the specified BufferedReader, removing leading and trailing whitespace and comments.
`void`	`setNameState(String name, int prefState)` Enable MarshalInputStream to optimize preference information: permits complete name expressions to be added for names that only match wild-card expressions.
`void`	`write(OutputStream out)` Write the preferences to the specified OutputStream using the preference list syntax.
`private void`	`writeMap(Map<String,Object> prefs, Writer out, String suffix)` Write the contents of the map into `out` using the preference syntax.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - NAME_NO_PREFERENCE
```
public static final int NAME_NO_PREFERENCE
```
    Constant value that indicates that there is no preference value for a given name.
    
    See Also:
    
    Constant Field Values
  - NAME_NOT_PREFERRED
```
public static final int NAME_NOT_PREFERRED
```
    Constant value that indicates that the resource for a given name is known to be not preferred. This state is applicable when a preference expression declared that the name is not preferred or when the resource for the name (preferred or not) is known to not exist.
    
    See Also:
    
    Constant Field Values
  - NAME_PREFERRED
```
public static final int NAME_PREFERRED
```
    Constant value that indicates that a given name is preferred. This state is applicable when a preference expression declares the name to be preferred but it is uncertain whether the resource for the name the exists.
    
    See Also:
    
    Constant Field Values
  - NAME_PREFERRED_RESOURCE_EXISTS
```
public static final int NAME_PREFERRED_RESOURCE_EXISTS
```
    Constant value that indicates that a given resource is preferred. This state is applicable when a preference expression declares the name to be preferred and the resource for the name is known to exist.
    
    See Also:
    
    Constant Field Values
  - HEADER_TITLE
```
private static final String HEADER_TITLE
```
    string that starts preference specification headers
    
    See Also:
    
    Constant Field Values
  - HEADER_MAJOR_VERSION
```
private static final String HEADER_MAJOR_VERSION
```
    See Also:
    
    Constant Field Values
  - HEADER_MINOR_VERSION
```
private static final String HEADER_MINOR_VERSION
```
    See Also:
    
    Constant Field Values
  - PREF_PREFIX
```
private static final String PREF_PREFIX
```
    preference syntax keywords
    
    See Also:
    
    Constant Field Values
  - NAME_PREFIX
```
private static final String NAME_PREFIX
```
    See Also:
    
    Constant Field Values
  - namespacePrefs
```
private final Map<String,Object> namespacePrefs
```
  - packagePrefs
```
private final Map<String,Object> packagePrefs
```
  - completeNamePrefs
```
private final Map<String,Object> completeNamePrefs
```
  - isEmpty
```
private volatile boolean isEmpty
```
    flag to signal if this preference object is empty
  - defaultPreference
```
private final Boolean defaultPreference
```
    default preference setting
- Constructor Detail
  - PreferredResources
```
public PreferredResources(InputStream in)
                   throws IOException
```
    Create a preference object from a stream of formatted preference syntax.
    
    Throws:
    
    IOException
    
    See Also:
    
    PreferredResources
- Method Detail
  - readLineTrimComments
```
private String readLineTrimComments(BufferedReader br)
                             throws IOException
```
    Reads the next line from the specified BufferedReader, removing leading and trailing whitespace and comments. Null is returned on EOF.
    
    Throws:
    
    IOException
  - mapPut
```
private void mapPut(Map<String,Object> map,
                    String name,
                    Object preference)
             throws IOException
```
    Insert a preference expression and value into a given map.
    
    Throws:
    
    IOException
  - write
```
public void write(OutputStream out)
           throws IOException
```
    Write the preferences to the specified OutputStream using the preference list syntax. Preference expressions are written in the following order: Complete name expressions Package expressions Namespace expressions
    
    Parameters:
    
    out - the stream to which formatted preference information will be written
    
    Throws:
    
    IOException - if an error occurs while writing to the stream
  - writeMap
```
private void writeMap(Map<String,Object> prefs,
                      Writer out,
                      String suffix)
               throws IOException
```
    Write the contents of the map into out using the preference syntax.
    
    Throws:
    
    IOException
  - getDefaultPreference
```
public Boolean getDefaultPreference()
```
    Returns the preference setting that will be applied to names which have no explicit preference setting in contained preference settings. The default preference is set by the first preference setting with no associated name in a preferences list file.
    
    Returns:
    
    default boolean preference value for these preferences
  - setNameState
```
public void setNameState(String name,
                         int prefState)
                  throws IOException
```
    Enable MarshalInputStream to optimize preference information: permits complete name expressions to be added for names that only match wild-card expressions. These added expressions hold data that tells if a resource has been loaded. This method makes this object mutable. Synchronization must be used to ensure consistent preference state when this method is called.
    
    Parameters:
    
    name - the name for which preferred state will be set
    
    prefState - the preferred state for the given name
    
    Throws:
    
    IOException - if the name length is zero length
  - getNameState
```
public int getNameState(String name,
                        boolean isClass)
                 throws IOException
```
    Searches the preference maps to determine the preference state of the named resource. The preference state for the given resource name is returned. The preference state is an integer that is equal to one of the preference state values defined above. This state integer tells the preference value of name and whether its resource is known to exist.
    
    Parameters:
    
    name -
    
    isClass - whether the given name refers to a class resource
    
    Returns:
    
    the state for the given name which will be set to one of the following values: NAME_NO_PREFERENCE, NAME_NOT_PREFERRED, NAME_PREFERRED, NAME_PREFERRED_RESOURCE_EXISTS
    
    Throws:
    
    IOException - if an error occurs getting the state for the supplied name
  - getClassNameState
```
private Integer getClassNameState(String name)
                           throws IOException
```
    Returns the preference state for a given name (as is done in getNonclassNameState) but also interprets the notation for inner classes as a wild card so that the preference value for a container class propagates to the classes it contains. More specific inner classes names override more general container preference.
    
    Throws:
    
    IOException
  - getWildcardPreference
```
public Boolean getWildcardPreference(String name)
```
    Return the boolean value of the most specific wild card (package and namespace) expression which matches name. Package preferences are always more specific than namespace preferences.
    
    Parameters:
    
    name - the resource name to which the returned boolean value will apply
    
    Returns:
    
    Boolean.TRUE/code> if name is preferred. Boolean.FALSE is it is not. null if there is no wildcard preference for the name.
  getNamespacePreference private Boolean getNamespacePreference(String namespace) Return a Boolean for the most specific namespace expression which matches name. null if the name does not match a namespace preference expression.

Class PreferredResources

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NAME_NO_PREFERENCE

NAME_NOT_PREFERRED

NAME_PREFERRED

NAME_PREFERRED_RESOURCE_EXISTS

HEADER_TITLE

HEADER_MAJOR_VERSION

HEADER_MINOR_VERSION

PREF_PREFIX

NAME_PREFIX

namespacePrefs

packagePrefs

completeNamePrefs

isEmpty

defaultPreference

Constructor Detail

PreferredResources

Method Detail

readLineTrimComments

mapPut

write

writeMap

getDefaultPreference

setNameState

getNameState

getClassNameState

getWildcardPreference

getNamespacePreference