JspComponentPeer

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echopoint.ui.jsp
Class JspComponentPeer

java.lang.Object
  nextapp.echoservlet.ComponentPeer
      echopoint.ui.util.EchoPointComponentPeer
          echopoint.ui.jsp.JspComponentPeer

All Implemented Interfaces:: java.util.EventListener, nextapp.echo.event.ImageUpdateListener, echopoint.ui.util.PeerDelegate, java.beans.PropertyChangeListener, nextapp.echoservlet.html.Renderable, java.io.Serializable

public abstract class JspComponentPeer
extends echopoint.ui.util.EchoPointComponentPeer
implements nextapp.echoservlet.html.Renderable, nextapp.echo.event.ImageUpdateListener

JspComponentPeer is an abstract component peer class that allows JSP page fragments to be used to render a component.

This class is useful if you prefer updating JSP/HTML markup rather than writing Java nextapp.echoservlet.html.Element statements.

To use this class you need to implement the method getJspPath(). as this nominates the JSP path to include as peer content. You might want to use different JSP pages depending on the state of the underlying component.

You will very likely want to overide preRender() as well. This method allows any ComponentStyle's and scripts to be added to the Echo HTML document. You might also want to add beans to the HttpSession or HttpServletRequest objects at this time.

The results of these pre-render methods are then available inside the JSP page because JspComponentPeer adds itself as a request scope attribute called "echopoint.ui.jsp.JspComponentPeer" or in Java terms JspComponentPeer.JSPCOMPONENTPEER.

You can then access the peer in the JSP page as follows :

      ...
      <%@ page language="java" %>
      <%@ page import="echopoint.ui.jsp.JspComponentPeer" %>
      <%@ page import="com.yourcompany.*" %>
      <%
      JspComponentPeer peer = (JspComponentPeer) request.getAttribute(JspComponentPeer.JSPCOMPONENTPEER);
      YourCustomComponent customC = (YourCustomComponent) peer.getComponent();
      Component child = customC.getTopBit();
      %>
      ...
      ...
      <span class="<%=peer.getStyle("topLineBit")%>" > Some styled text </span>
      <div class="<%=peer.getStyle("contentBit")%>" >
      <%
         peer.renderChild(out,child);  
      %>
      </div>
      <image src="<%=peer.getStyle("contentBit")%>" >

You will also have to associated your custom peer with its component via a method such as :

 public static void register() {
       nextapp.echoservlet.EchoServer.loadPeerBindings("mycompany.ui.MyCustomComponent");
 }

This class differs from the other JSP integration class JspTemplatePanel in a number of ways. Firstly it only evaluates the JSP once, at the time the Echo servlet is writing to the servlet stream. Secondly it does not allow "styles" to be dynamically evaluated like in a JspTemplatePanel. And finally while it allows child components to be embedded in the output, they are always pre-rendered and are not "named" via the special JSP tags.

Field Summary

private java.util.Map childElementMap


private javax.servlet.jsp.JspFactory factory


private boolean isLoudErrorsUsed


static java.lang.String JSPCOMPONENTPEER
          This string is used as the request scope attribute name which holds this JspComponentPeer object.

private java.lang.String jspPath


private javax.servlet.jsp.PageContext pageContext


private nextapp.echoservlet.RenderingContext rc


private javax.servlet.http.HttpServletRequest request


private javax.servlet.http.HttpServletResponse response


private javax.servlet.Servlet servlet


private javax.servlet.http.HttpSession session


private java.util.Map styleMap


Fields inherited from class echopoint.ui.util.EchoPointComponentPeer

imageManager, renderedActive, toolTipHelper

Fields inherited from class nextapp.echoservlet.ComponentPeer

Fields inherited from interface nextapp.echoservlet.html.Renderable

INDENT_STRING

Constructor Summary

JspComponentPeer()


Method Summary

java.lang.String classEquals(java.lang.String styleKey)
          This is a synonym for the getStyle() method but it adds the text class="xxx" for you.

javax.servlet.jsp.JspFactory getFactory()
          Returns the JSPFactory currently in use or null if none is available.

java.lang.String getImageUri(java.lang.String imageName)
          This will return the URI for a managed image or null if it can not be found.

protected abstract java.lang.String getJspPath()
          This abstract method is required to return the path of the JSP page that will be included as the content of this component peer.

javax.servlet.jsp.PageContext getPageContext()
          Returns the PageContext currently in use or null if none is available.

nextapp.echoservlet.RenderingContext getRenderingContext()
          Returns the current RenderingContext associated with the peer or null if none is available.

javax.servlet.http.HttpServletRequest getRequest()
          Returns the HttpServletRequest currently in use or null if none is available.

javax.servlet.http.HttpServletResponse getResponse()
          Returns the HttpServletResponse currently in use or null if none is available.

javax.servlet.Servlet getServlet()
          Returns the Servlet currently in use or null if none is available.

javax.servlet.http.HttpSession getSession()
          Returns the HttpSession currently in use or null if none is available.

java.lang.String getStyle(java.lang.String styleKey)
          Returns the Echo style name that was previously stored away using the putStyle() method.

java.lang.String imgEquals(java.lang.String imageName)
          Synonym for imgEquals(imageName,"");

java.lang.String imgEquals(java.lang.String imageName, java.lang.String extraAttributes)
          This is a synonym for the getImageUri() method but it adds the text <img src="xxx" width="nnn" height="nnn" ...> plus any extra attribuets that have been provided on the call.

boolean isLoudErrorsUsed()
          Returns true if loud error message generation is used.

private java.lang.String preNewLines(java.lang.String s)


protected void preRender(nextapp.echoservlet.RenderingContext rc)
          This is called to setup any objects needed before the actual JSP page is invoked.

protected java.lang.String putStyle(java.lang.String styleKey, nextapp.echoservlet.ComponentStyle componentStyle)
          This method is an easy way to add completed ComponentStyle objects to the document.

void render(java.io.PrintWriter pw, int depth, boolean parentWhitespaceRelevant)
          This method is called during Echo servlet output and it includes the actual JSP content that has been setup for this component peer via getJspPath().

void render(nextapp.echoservlet.RenderingContext rc, nextapp.echoservlet.html.Element parent)
          The render method has been made final.

void renderChild(java.io.Writer out, nextapp.echo.Component childComponent)
          This method is available so that the JSP can render a child of the main component.

private void reportError(java.io.PrintWriter pw, javax.servlet.ServletException e)
          Report a ServletError, in all likely hood an JSP compile error, by make it more pretty.

void setLoudErrorsUsed(boolean isLoudErrorsUsed)
          If this is set to true, then a loud, obvious HTML error will be output if some catatrophic error occurs during JSP rendering.

Methods inherited from class echopoint.ui.util.EchoPointComponentPeer

addOnce, addOnce, addScriptInclude, copyChildrenExcept, copyChildrenExcept, forComponent, forComponent, getChildren, getImage, getImageManager, getImageUri, getPeer, getPeer, getToolTipHelper, getUri, hasBeenAdded, imageUpdate, propertyChange, registered, removeAllImages, removeAllManagedImages, removeNewLinesAndJSQuote, removeNewLinesAndJSQuote, setImage, trackImage, unregistered

Methods inherited from class nextapp.echoservlet.ComponentPeer

addAncillaryService, generateId, getBackground, getChildCount, getComponent, getFocusedElementId, getFont, getForeground, getId, getInstancePeer, getParent, getTabIndex, redraw, removeAncillaryService

Methods inherited from class java.lang.Object

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

Methods inherited from interface nextapp.echo.event.ImageUpdateListener

imageUpdate

Methods inherited from interface echopoint.ui.util.PeerDelegate

getId

Field Detail

JSPCOMPONENTPEER

public static final java.lang.String JSPCOMPONENTPEER

This string is used as the request scope attribute name which holds this JspComponentPeer object.

See Also:: Constant Field Values

rc

private nextapp.echoservlet.RenderingContext rc

pageContext

private javax.servlet.jsp.PageContext pageContext

factory

private javax.servlet.jsp.JspFactory factory

servlet

private javax.servlet.Servlet servlet

request

private javax.servlet.http.HttpServletRequest request

response

private javax.servlet.http.HttpServletResponse response

session

private javax.servlet.http.HttpSession session

childElementMap

private java.util.Map childElementMap

styleMap

private java.util.Map styleMap

jspPath

private java.lang.String jspPath

isLoudErrorsUsed

private boolean isLoudErrorsUsed

Constructor Detail

JspComponentPeer

public JspComponentPeer()

Method Detail

render

public final void render(nextapp.echoservlet.RenderingContext rc,
                         nextapp.echoservlet.html.Element parent)

The render method has been made final. This method now sets up the objects needed during the actual JSP rendering, such as the JSP page to include, any scripts or component style names required and will then pre-render any child components.

The order is as follows :

getJspPath() is called
preRender() is called
any child peers are pre-rendered

render

public final void render(java.io.PrintWriter pw,
                         int depth,
                         boolean parentWhitespaceRelevant)

This method is called during Echo servlet output and it includes the actual JSP content that has been setup for this component peer via getJspPath().

Specified by:: render in interface nextapp.echoservlet.html.Renderable

reportError

private void reportError(java.io.PrintWriter pw,
                         javax.servlet.ServletException e)

Report a ServletError, in all likely hood an JSP compile error, by make it more pretty.

preNewLines

private java.lang.String preNewLines(java.lang.String s)

putStyle

protected java.lang.String putStyle(java.lang.String styleKey,
                                    nextapp.echoservlet.ComponentStyle componentStyle)

This method is an easy way to add completed ComponentStyle objects to the document. The Echo generated name is returned.

These component style names can then be used in class="xxx" statements inside the JSP markup.

A style keyed as "default" is initially primed and is equivalent to ComponentStyle.forComponent(this);

getStyle

public java.lang.String getStyle(java.lang.String styleKey)

Returns the Echo style name that was previously stored away using the

putStyle() method.  This is very useful
 in HTML class="...." statements inside the JSP.
 
 Usage is demonstrated in the following JSP fragment :
 

 
      ...
      <%@ page language="java" %>
      <%@ page import="echopoint.ui.jsp.JspComponentPeer" %>
      <%
      JspComponentPeer peer = (JspComponentPeer) request.getAttribute(JspComponentPeer.JSPCOMPONENTPEER);
      %>
      ...
      ...
      <span class="<%=peer.getStyle("topLineBit")" %> Some styled text </span>





classEquals
public java.lang.String classEquals(java.lang.String styleKey)

This is a synonym for the getStyle() method but it
 adds the text class="xxx" for you.  It allows you to write
 
 
      <span <%=peer.classEquals("topLineBit")%> > Some styled text </span>
 
 
 instead of the slightly more terse :
 

 
      <span class="<%=peer.getStyle("topLineBit")" %> > Some styled text </span>
 











getImageUri
public java.lang.String getImageUri(java.lang.String imageName)

This will return the URI for a managed image or null if it
 can not be found.











imgEquals
public java.lang.String imgEquals(java.lang.String imageName)

Synonym for imgEquals(imageName,"");











imgEquals
public java.lang.String imgEquals(java.lang.String imageName,
                                  java.lang.String extraAttributes)

This is a synonym for the getImageUri() method but it
 adds the text <img src="xxx" width="nnn" height="nnn" ...> plus
 any extra attribuets that have been provided on the call. 
 
 It allows you to write
 

 
      <%=peer.imgEquals("imageName1","vspace=5")%>
 
 
 instead of the slightly more terse :
 

 
      <img src="<%=peer.getImageUri("imageName1")%>" width="nnn" height="nnn" vspace=5 >
 











renderChild
public void renderChild(java.io.Writer out,
                        nextapp.echo.Component childComponent)

This method is available so that the JSP can render a child 
 of the main component.  They key to use is the actual 
 child component itself.  
 
 Child components of the peers main component are pre-rendered
 during the intital setup, before the JSP page is rendered.  You
 can use this method to access the pre-rendered child components
 inside the JSP markup itself.
 

 Usage is demonstrated in the following JSP fragment :
 

 
      ...
      <%@ page language="java" %>
      <%@ page import="echopoint.ui.jsp.JspComponentPeer" %>
      <%@ page import="com.yourcompany.*" %>
      <%
      JspComponentPeer peer = (JspComponentPeer) request.getAttribute(JspComponentPeer.JSPCOMPONENTPEER);
      YourCustomComponent customC = (YourCustomComponent) peer.getComponent();
      Component child = customC.getTopBit();
      %>
      ...
      ...
      <div>
      <%
         peer.renderChild(out,child);  
      %>
      </div>
 











getRenderingContext
public nextapp.echoservlet.RenderingContext getRenderingContext()

Returns the current RenderingContext associated with the peer or null if none is available.











getFactory
public javax.servlet.jsp.JspFactory getFactory()

Returns the JSPFactory currently in use or null if none is available.











getPageContext
public javax.servlet.jsp.PageContext getPageContext()

Returns the PageContext currently in use or null if none is available.











getRequest
public javax.servlet.http.HttpServletRequest getRequest()

Returns the HttpServletRequest currently in use or null if none is available.











getResponse
public javax.servlet.http.HttpServletResponse getResponse()

Returns the HttpServletResponse currently in use or null if none is available.











getServlet
public javax.servlet.Servlet getServlet()

Returns the Servlet currently in use or null if none is available.











getSession
public javax.servlet.http.HttpSession getSession()

Returns the HttpSession currently in use or null if none is available.











isLoudErrorsUsed
public boolean isLoudErrorsUsed()

Returns true if loud error message generation is used.











setLoudErrorsUsed
public void setLoudErrorsUsed(boolean isLoudErrorsUsed)

If this is set to true, then a loud, obvious HTML error
 will be output if some catatrophic error occurs
 during JSP rendering.  Otherwise a quite HTML
 comment will be emitted.











getJspPath
protected abstract java.lang.String getJspPath()

This abstract method is required to return the path of the JSP page 
 that will be included as the content of this component peer.  
 It must be non null and non-empty, otherwise an
 IllegalStateException is thrown.











preRender
protected void preRender(nextapp.echoservlet.RenderingContext rc)

This is called to setup any objects needed before
 the actual JSP page is invoked.  This could include
 things such as ComponentStyle objects and any
 special scripts and services required.
 
 You might also want to add beans to the HttpSession or 
 HttpServletRequest objects at this time.  
 

 These scripts etc.. can be added to the head of the HTML document because 
 this method is called before actual JSP rendering occurs.
 

 This implementation of the method adds a ComponentStyle
 mapped as "default", via is built via 
 ComponentStyle.forComponent(this);

















  
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Field Summary
`private java.util.Map`	`childElementMap`
`private javax.servlet.jsp.JspFactory`	`factory`
`private boolean`	`isLoudErrorsUsed`
`static java.lang.String`	`JSPCOMPONENTPEER` This string is used as the request scope attribute name which holds this JspComponentPeer object.
`private java.lang.String`	`jspPath`
`private javax.servlet.jsp.PageContext`	`pageContext`
`private nextapp.echoservlet.RenderingContext`	`rc`
`private javax.servlet.http.HttpServletRequest`	`request`
`private javax.servlet.http.HttpServletResponse`	`response`
`private javax.servlet.Servlet`	`servlet`
`private javax.servlet.http.HttpSession`	`session`
`private java.util.Map`	`styleMap`

Method Summary
`java.lang.String`	`classEquals(java.lang.String styleKey)` This is a synonym for the `getStyle()` method but it adds the text class="xxx" for you.
`javax.servlet.jsp.JspFactory`	`getFactory()` Returns the JSPFactory currently in use or null if none is available.
`java.lang.String`	`getImageUri(java.lang.String imageName)` This will return the URI for a managed image or null if it can not be found.
`protected abstract java.lang.String`	`getJspPath()` This abstract method is required to return the path of the JSP page that will be included as the content of this component peer.
`javax.servlet.jsp.PageContext`	`getPageContext()` Returns the PageContext currently in use or null if none is available.
`nextapp.echoservlet.RenderingContext`	`getRenderingContext()` Returns the current RenderingContext associated with the peer or null if none is available.
`javax.servlet.http.HttpServletRequest`	`getRequest()` Returns the HttpServletRequest currently in use or null if none is available.
`javax.servlet.http.HttpServletResponse`	`getResponse()` Returns the HttpServletResponse currently in use or null if none is available.
`javax.servlet.Servlet`	`getServlet()` Returns the Servlet currently in use or null if none is available.
`javax.servlet.http.HttpSession`	`getSession()` Returns the HttpSession currently in use or null if none is available.
`java.lang.String`	`getStyle(java.lang.String styleKey)` Returns the Echo style name that was previously stored away using the `putStyle() method.`
`java.lang.String`	`imgEquals(java.lang.String imageName)` Synonym for imgEquals(imageName,"");
`java.lang.String`	`imgEquals(java.lang.String imageName, java.lang.String extraAttributes)` This is a synonym for the `getImageUri()` method but it adds the text <img src="xxx" width="nnn" height="nnn" ...> plus any extra attribuets that have been provided on the call.
`boolean`	`isLoudErrorsUsed()` Returns true if loud error message generation is used.
`private java.lang.String`	`preNewLines(java.lang.String s)`
`protected void`	`preRender(nextapp.echoservlet.RenderingContext rc)` This is called to setup any objects needed before the actual JSP page is invoked.
`protected java.lang.String`	`putStyle(java.lang.String styleKey, nextapp.echoservlet.ComponentStyle componentStyle)` This method is an easy way to add completed ComponentStyle objects to the document.
`void`	`render(java.io.PrintWriter pw, int depth, boolean parentWhitespaceRelevant)` This method is called during Echo servlet output and it includes the actual JSP content that has been setup for this component peer via getJspPath().
`void`	`render(nextapp.echoservlet.RenderingContext rc, nextapp.echoservlet.html.Element parent)` The render method has been made final.
`void`	`renderChild(java.io.Writer out, nextapp.echo.Component childComponent)` This method is available so that the JSP can render a child of the main component.
`private void`	`reportError(java.io.PrintWriter pw, javax.servlet.ServletException e)` Report a ServletError, in all likely hood an JSP compile error, by make it more pretty.
`void`	`setLoudErrorsUsed(boolean isLoudErrorsUsed)` If this is set to true, then a loud, obvious HTML error will be output if some catatrophic error occurs during JSP rendering.

echopoint.ui.jsp Class JspComponentPeer

JSPCOMPONENTPEER

rc

pageContext

factory

servlet

request

response

session

childElementMap

styleMap

jspPath

isLoudErrorsUsed

JspComponentPeer

render

render

reportError

preNewLines

putStyle

getStyle

classEquals

getImageUri

imgEquals

imgEquals

renderChild

getRenderingContext

getFactory

getPageContext

getRequest

getResponse

getServlet

getSession

isLoudErrorsUsed

setLoudErrorsUsed

getJspPath

preRender

echopoint.ui.jsp
Class JspComponentPeer