org.omegahat.Environment.Tools.ClassList
Class ClassLocator

java.lang.Object
  |
  +--java.util.Dictionary
        |
        +--java.util.Hashtable
              |
              +--org.omegahat.Environment.Utils.OrderedTable
                    |
                    +--org.omegahat.Environment.Tools.ClassList.ClassLocator

All Implemented Interfaces:

Activable, AssignableSubset, ClassLocatorInt, java.lang.Cloneable, Database, java.util.Map, java.io.Serializable, ShallowCopyable, Subsettable

Direct Known Subclasses:

LocalClassLocator

public class ClassLocator

extends OrderedTable

implements ClassLocatorInt, java.io.Serializable

Find class definitions, more generally and flexibly than in Java

The methods in this class maintain and use a search path for Java classes. Given the name of a class, the findClass method looks it up and returns the class object. It tries harder than the Java method in class ClassLoader, allowing partial specification of the class name. More importantly, the class supports a dynamic list of where to look, with facilities for adding to the list.

The elements in the class list each identify a source for class definitions. That source can be a directory containing class files, a jar file, or a location (URL) on the web. Methods taking strings as input will try to resolve these sources; methods taking files or URLs as arguments accept the arguments as provided. In addition, a ClassList object, however computed, can be an element of the locator's internal list.

The methods provided allow for adding individual elements or appending multiple elements from any of these sources.

See Also:

Serialized Form

Inner classes inherited from class java.util.Map

java.util.Map.Entry

Fields inherited from class org.omegahat.Environment.Utils.OrderedTable

listeners, name, orderedElements, orderedKeys, state

Fields inherited from interface org.omegahat.Environment.Databases.Database

ALL, ASSIGN, ATTACH, DETACH, NULL_ENTRY, READ, READ_WRITE, REMOVE

Fields inherited from interface org.omegahat.Environment.Databases.Activable

ACTIVE, INACTIVE

Constructor Summary

ClassLocator()

ClassLocator(ClassList list)
initialize from another list of class lists (see general discussion above)

ClassLocator(java.io.File f)
initialize from a file or directory (see general discussion above)

ClassLocator(java.lang.String[] els)
initialize from strings (see general discussion above)

ClassLocator(java.net.URL u)
initialize from a URL object (see general discussion above)

ClassLocator(java.util.Vector els)
initialize from objects (see general discussion above)

Method Summary

java.lang.Object	add(ClassList list) add another list of class lists (see general discussion above)
java.lang.Object	add(java.io.File f) add a file or directory (see general discussion above)
java.lang.Object	add(java.io.File[] f)
java.lang.Object	add(java.lang.Object o) add an object (see general discussion above)
java.lang.Object	add(java.lang.String name) add class list identified by a string (see general discussion above)
java.lang.Object	add(java.lang.String[] names)
java.lang.Object	add(java.net.URL u) add a URL object (see general discussion above)
java.lang.Object	add(java.net.URL[] u)
int	append(java.lang.String[] els) append from strings (see general discussion above)
int	append(java.util.Vector els) append objects (see general discussion above)
boolean	canReadSerializedLists(java.io.File f) Determines whether read a serialized version of the list representing the specified file is acceptable.
ClassList	classList(java.io.File f) Creates an appropriate ClassList object based on the characteristics of the specified file.
ClassList	classList(java.io.File f, java.lang.String asSub)
ClassList	classList(java.net.URL u) Constructs a class list based on the contents of the URL.
ClassList	classList(java.net.URL u, java.lang.String asSub)
java.lang.Class	findClass(java.lang.String name) Find a class by looking through the elements of the list in order and querying them for a match of the name.
java.util.Vector	findClasses(java.lang.String name, java.util.Vector classes) Find all the matching classes rather than just the first one
java.lang.String	serializedName(java.io.File f) The name of the class property corresponding to the serialized version of the ClassList object for the specified file.

Methods inherited from class org.omegahat.Environment.Utils.OrderedTable

add, addListListener, assign, assignSubset, attach, clear, copy, copy, detach, elementAt, exists, get, getName, getState, keys, listeners, listeners, notifyListeners, objects, ordered, orderedKeys, put, put, put, remove, remove, removeElement, removeElement, removeElementAt, removeElementAt, removeListListener, setElementAt, setName, setState, subset, subset, subset

Methods inherited from class java.util.Hashtable

clone, contains, containsKey, containsValue, elements, entrySet, equals, get, hashCode, isEmpty, keySet, putAll, rehash, size, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.omegahat.Environment.Tools.ClassList.ClassLocatorInt

containsKey, elements, get, orderedKeys, size

Methods inherited from interface org.omegahat.Environment.Databases.Database

size

Constructor Detail

ClassLocator

public ClassLocator()

ClassLocator

public ClassLocator(java.lang.String[] els)

initialize from strings (see general discussion above)

ClassLocator

public ClassLocator(java.util.Vector els)

initialize from objects (see general discussion above)

ClassLocator

public ClassLocator(java.io.File f)

initialize from a file or directory (see general discussion above)

ClassLocator

public ClassLocator(java.net.URL u)

initialize from a URL object (see general discussion above)

ClassLocator

public ClassLocator(ClassList list)

initialize from another list of class lists (see general discussion above)

Method Detail

findClass

public java.lang.Class findClass(java.lang.String name)
                          throws java.lang.ClassNotFoundException

Find a class by looking through the elements of the list in order and querying them for a match of the name. This performs some processing on the name to replace . with the file separator.

Specified by:

findClass in interface ClassLocatorInt

findClasses

public java.util.Vector findClasses(java.lang.String name,
                                    java.util.Vector classes)

Description copied from interface: ClassLocatorInt

Find all the matching classes rather than just the first one

Specified by:

findClasses in interface ClassLocatorInt

add

public java.lang.Object add(java.io.File f)

add a file or directory (see general discussion above)

add

public java.lang.Object add(java.io.File[] f)

add

public java.lang.Object add(java.net.URL u)

add a URL object (see general discussion above)

add

public java.lang.Object add(java.net.URL[] u)

add

public java.lang.Object add(ClassList list)

add another list of class lists (see general discussion above)

add

public java.lang.Object add(java.lang.String name)

add class list identified by a string (see general discussion above)

Specified by:

add in interface ClassLocatorInt

add

public java.lang.Object add(java.lang.String[] names)

add

public java.lang.Object add(java.lang.Object o)

add an object (see general discussion above)

Overrides:

add in class OrderedTable

classList

public ClassList classList(java.io.File f)

Creates an appropriate ClassList object based on the characteristics of the specified file. If first sees if it can read a serialized version associated with this file. It does so by using this class' getResource() method.

classList

public ClassList classList(java.io.File f,
                           java.lang.String asSub)

Parameters:

f - the file.

asSub - indicates whether the created ClassList will be used as part of an import statement with a sub-directory restricting the set of classes.

classList

public ClassList classList(java.net.URL u)

Constructs a class list based on the contents of the URL. This should be a zip or jar file.

classList

public ClassList classList(java.net.URL u,
                           java.lang.String asSub)

append

public int append(java.util.Vector els)

append objects (see general discussion above)

append

public int append(java.lang.String[] els)

append from strings (see general discussion above)

canReadSerializedLists

public boolean canReadSerializedLists(java.io.File f)

Determines whether read a serialized version of the list representing the specified file is acceptable. This can be used to control whether we want to dynamically compute the list now or read it from a pre-computed value. In the case that we are a developer, this should be false.

serializedName

public java.lang.String serializedName(java.io.File f)

The name of the class property corresponding to the serialized version of the ClassList object for the specified file.