cl.obcom.netclient

Class LayoutManager

java.lang.Object

cl.obcom.netclient.LayoutManager

public final class LayoutManager
extends Object

Implements a collection (cache) of reusable Layout instances. If a requiered Layout is not in this collection, then its specification is downloaded, compiled, verified and added to the collection. Layouts are downloaded using the URI (Uniform Resource Identifier) supplied to the LayoutManager(String) constructor. This URI must contain at least one occurrence of the special placeholder character "*". Before each download, all occurrences of this placeholder are replaced with the name of the requiered Layout. In this way the resulting URI gets targeted specifically to the required Layout. Examples of valid URIs:

 http://www.obcom.cl/desktop/recs/*.asp
 file:/C:/websphere/dsn/web/recs/*.jsp
 ecuser://JSERVER?FormName=*

The last example shows a URI defined with the protocol ecuser. This non-standard protocol is used to download layout specifications from a server called ECUSER. This server is reached by sending transactions via a ClientChannel whose name matches the name of the host of the URI. In the previous example, the required ClientChannel is called JSERVER. This ClientChannel must be created before this LayoutManager can be used.

See Also:

Layout, ClientChannel.create(String, String, String)

Constructor Summary

Constructors

Constructor and Description
LayoutManager(String uri) Creates a new LayoutManager for the specified Uniform Resource Identifier (URI).

Method Summary

Modifier and Type	Method and Description
void	clear() Clears (removes) all layouts from the cache.
Layout	getLayout(String name) Returns a Layout with the specified name.
String	getURI() Returns the Uniform Resource Identifier (URI) of this LayoutManager.
Iterator<Layout>	iterator() Returns a "read-only" iterator over the collection of layouts in this LayoutManager.
Layout	putLayout(Layout layout) Adds a layout to the collection of layouts of this LayoutManager.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LayoutManager

public LayoutManager(String uri)

Creates a new LayoutManager for the specified Uniform Resource Identifier (URI). This URI must contain at least one occurrence of the special placeholder "*". Before a Layout is downloaded, all occurrences of this placeholder are replaced with the name of this Layout. In this way the resulting URI gets targeted specifically to the required Layout.

Parameters:

uri - the Uniform Resource Identifier (URI) of layouts.

Throws:

NullPointerException - if the supplied uri is null.

Method Detail

getURI

public String getURI()

Returns the Uniform Resource Identifier (URI) of this LayoutManager.

Returns:

the URI of this LayoutManager.

See Also:

LayoutManager(String)

iterator

public Iterator<Layout> iterator()

Returns a "read-only" iterator over the collection of layouts in this LayoutManager. Each object returned by the Iterator.next() method corresponds to a Layout object.

Returns:

a "read-only" iterator over the collection of layouts in this LayoutManager.

See Also:

Iterator.next(), Iterator.hasNext()

clear

public void clear()

Clears (removes) all layouts from the cache.

putLayout

public Layout putLayout(Layout layout)

Adds a layout to the collection of layouts of this LayoutManager. The layout must be non-null and complete as defined by the Layout.isComplete() method. This method returns the previous layout with the same name as the supplied layout, or null if it did not have one.

Parameters:

layout - the layout to add to this LayoutManager.

Returns:

the previous layout with the same name as the supplied layout, or null if it did not have one.

Throws:

NullPointerException - if layout is null.

IllegalArgumentException - if layout is not complete.

See Also:

Layout.isComplete()

getLayout

public Layout getLayout(String name)

Returns a Layout with the specified name. If the Layout is not in the cache, it downloads its specification, compiles it, verifies its MD5 signature (or checksum), and then stores the resulting Layout in the cache. If any step in this process fails, it throws an exception.

Parameters:

name - name of the required Layout.

Returns:

the required layout.

Throws:

NullPointerException - if name is null or empty.