com.sas.collection
Class StaticStringList

com.sas.collection.StaticStringList

All Implemented Interfaces:

com.sas.beans.PropertyChangeSource, com.sas.beans.VetoableChangeSource, com.sas.collection.ContentsChangedListener, com.sas.collection.ContentsChangedSource, StaticCollectionInterface, StaticStringListInterface, ComponentInterface, LinkPropertiesInterface, ModelInterface, com.sas.PublicClonable, com.sas.util.Countable, com.sas.util.Enumerable, com.sas.util.EventGateInterface, ViewInterface, MultipleValueEventSourceInterface, java.beans.PropertyChangeListener, java.io.ObjectInputValidation, java.io.Serializable, java.lang.Cloneable, java.util.EventListener

public class StaticStringList
implements StaticStringListInterface

A StaticStringList is a class which hides the update methods of a StringList object. This is useful if you have an object which has an internal StringList and you would like to make available read-only access to that StringList. To do so, you could provide a public method which return the type StaticStringListInterface:

   private StringListInterface members;
   // or perhaps private StringList members
   public StaticStringListInterface getMembers()
   { return new StaticStringList(members); }
 

but someone can always bypass this by checking if a StaticStringListInterface is really a StringListInterface:

 StaticStringListInterface sc = yourObject.getMembers();
 if (sc instanceof StringListInterface)
 {
    StringListInterface c = (StringListInterface) sc;
    // wreak havoc with your StringList
 }
 

The StaticStringList class provides an elegant way around this by creating an object which cannot be cast to a StringCollection or StringListInterface.

A recommended way for your to use the StaticStringList class is to only create it once and always return that reference.

   private StaticStringList sc;
   public StaticStringListInterface getMembers()
   {
     if (sc == null)
        sc = new StaticStringList(members);
     return sc;
   }
 

Note, however, that if you create a new members collection, you will need to create a new StaticStringList object as well, since there is no way to change the StringListInterface that the StaticStringList refers to. Also, be aware that in such cases, other object which hold references to your old StaticStringList object will have stale object references.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.sas.collection.BaseCollection

allContentsChangedListeners, mappingObject

Constructor Summary

StaticStringList(StaticStringListInterface strings)
Create a StaticStringList which provides read-only access to another string list.

Method Summary

boolean	contains(java.lang.Object object) Test if a collection contains an object.
int	count() Return the number of items in this string collection.
boolean	equals(StaticStringListInterface list) Compare the current items with those in another StaticStringList and tell whether the lists are identical.
int	getIndex(java.lang.String item, int startIndex) Returns the index associated with the item (searches forward)
java.util.Enumeration	getItems() Get an enumeration of this collection's contents.
int	getLastIndex(java.lang.String item, int startIndex) Returns the index associated with the item (searches backward)
java.lang.String	getString(int index) Fetch a string at a index.
java.lang.String[]	getStringItems() Return the Strings in this string list as an array of String.
StaticStringListInterface	getStringItems(int start, int last) Extract a sublist of items from this string list

Methods inherited from class com.sas.collection.CollectionMirror

addContentsChangedListener, clone, contentsChanged, equals, getSource, hashCode, removeContentsChangedListener, toString

Methods inherited from class com.sas.collection.BaseCollection

anyContentsChangedListeners, apply, disableEvents, enableEvents, enableEvents, fireContentsChanged, map, unmap

Methods inherited from class com.sas.Component

addLink, addPropertyChangeListener, addVetoableChangeListener, anyPropertyChangeListeners, attachModel, attachView, beansIsDesignTime, beansSetDesignTime, clone, detachModel, detachView, dumpComponent, firePropertyChange, firePropertyChange, fireVetoableChange, getComponentDescription, getComponentSupportInfo, getEventMethod, getEventValues, getExtendedBeanInfo, getLinkInfo, getModelInterface, getRequiredInterfaces, getResources, getStringResource, getViewInterfaceSupportInfo, initialize, initializeComponent, isDesignTime, isLinked, propertyChange, queryLinks, queryLinks, refresh, removeAllLinks, removeInterfaceTraps, removeLink, removePropertyChangeListener, removeVetoableChangeListener, setComponentDescription, setComponentSupportInfo, setDefaultValues, setLinkInfo, setModelInterface, setRequiredInterfaces, setViewInterfaceSupportInfo, supportsListenerInterface, supportsRequiredInterfaces, trapInterfaceEvents, validateObject

Methods inherited from interface com.sas.collection.StaticStringListInterface

clone

Methods inherited from interface com.sas.collection.ContentsChangedSource

addContentsChangedListener, removeContentsChangedListener

Methods inherited from interface com.sas.beans.PropertyChangeSource

addPropertyChangeListener, removePropertyChangeListener

Constructor Detail

StaticStringList

public StaticStringList(StaticStringListInterface strings)

Create a StaticStringList which provides read-only access to another string list.

Parameters:

strings - a string list. Note that the parameter type is StaticStringListInterface but normally the actual collection passed will implement StringListInterface

Method Detail

equals

public boolean equals(StaticStringListInterface list)

Compare the current items with those in another StaticStringList and tell whether the lists are identical. The equals method is used to compare the Strings.

Specified by:

equals in interface StaticStringListInterface

Parameters:

list - Another string list to be compared to.

Returns:

true if identical, false otherwise.

getIndex

public int getIndex(java.lang.String item,
                    int startIndex)

Returns the index associated with the item (searches forward)

Specified by:

getIndex in interface StaticStringListInterface

Parameters:

item - item to search for

startIndex - index where search should start

Returns:

the zero-based index corresponding to the list item or -1 if the item is not found

Throws:

java.lang.IndexOutOfBoundsException - if the start index is not in the range [0..count()-1]

getStringItems

public java.lang.String[] getStringItems()

Return the Strings in this string list as an array of String.

Specified by:

getStringItems in interface StaticStringListInterface

Returns:

an arracy of the String values in this string list.

getStringItems

public StaticStringListInterface getStringItems(int start,
                                                int last)

Extract a sublist of items from this string list

Specified by:

getStringItems in interface StaticStringListInterface

Parameters:

start - the index of the first item, zero based.

last - the index of the last item, zero based.

Returns:

a list of the selected elements.

Throws:

java.lang.IndexOutOfBoundsException - if start or last are not in the range [0, count()-1].

See Also:

StaticOrderedCollectionInterface.getItems(int, int), String.substring(int, int)

getLastIndex

public int getLastIndex(java.lang.String item,
                        int startIndex)

Returns the index associated with the item (searches backward)

Specified by:

getLastIndex in interface StaticStringListInterface

Parameters:

item - item to search for

startIndex - index where search should start

Returns:

int the zero-based index corresponding to the list item of -1 if the item is not found

Throws:

java.lang.IndexOutOfBoundsException - if the start index is not in the range [0..count()-1]

getString

public java.lang.String getString(int index)

Fetch a string at a index.

Specified by:

getString in interface StaticStringListInterface

Parameters:

the - position of the item, zero based indexing.

Returns:

String the item associated with the index value

Throws:

java.lang.IndexOutOfBoundsException - if index is not in the range [0, count-1].

count

public int count()

Return the number of items in this string collection.

Specified by:

count in interface com.sas.util.Countable

Specified by:

count in class BaseCollection

Returns:

the number of items in this string collection

getItems

public java.util.Enumeration getItems()

Get an enumeration of this collection's contents.

Specified by:

getItems in interface com.sas.util.Enumerable

Specified by:

getItems in class BaseCollection

Returns:

an enumeration of this collection's contents

See Also:

Enumerable.getItems()

contains

public boolean contains(java.lang.Object object)

Test if a collection contains an object.

Specified by:

contains in interface StaticCollectionInterface

Overrides:

contains in class BaseCollection

Parameters:

object - an object to find in this string collection.

Returns:

true if this string collection contains the object, false if not.

See Also:

StaticCollectionInterface.contains(java.lang.Object)