/*
* Copyright 2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* $Header:$
*/
package org.apache.beehive.netui.tags.html;
import org.apache.beehive.netui.tags.AbstractClassicTag;
import org.apache.beehive.netui.tags.ByRef;
import org.apache.beehive.netui.tags.ExpressionHandling;
import org.apache.beehive.netui.tags.rendering.AbstractHtmlControlState;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import java.util.List;
/**
* Abstract Base class adding support for the <code>dataSource</code> attribute.
*/
abstract public class HtmlDataSourceTag
extends HtmlFocusBaseTag
{
protected String _dataSource;
public HtmlDataSourceTag()
{
super();
}
/**
* Sets the tag's data source (can be an expression).
* @param dataSource the data source
* @jsptagref.attributedescription <p>The <code>dataSource</code> attribute determines both
* (1) the source of populating data for the tag and
* (2) the object to which the tag submits data.
*
* <p>For example, assume that the Controller file (= JPF file) contains
* a Form Bean with the property foo. Then the following <netui:textBox> tag will
* (1) draw populating data from the Form Bean's foo property and (2)
* submit user defined data to the same property.
*
* <p> <code><netui:textBox dataSource="actionForm.foo" /></code>
*
* <p>The <code>dataSource</code> attribute takes either a data binding expression or
* the name of a Form Bean property. In the
* above example, <code><netui:textBox dataSource="foo" /></code>
* would have the exactly same behavior.
*
* <p>When the tag is used to submit data, the data binding expression must
* refer to a Form Bean property.
* In cases where the tag is not used to submit data, but is used for
* displaying data only, the data
* binding expression need not refer to a Form Bean property. For example,
* assume that myIterativeData is a member variable on
* the Controller file ( = JPF file). The following <netui-data:repeater>
* tag draws its data from myIterativeData.
*
* <p> <code><netui-data:repeater dataSource="pageFlow.myIterativeData"></code>
* @jsptagref.databindable true
* @jsptagref.attributesyntaxvalue <i>expression_datasource</i>
* @netui:attribute required="true"
* description="The <code>dataSource</code> attribute determines both
* the source of populating data for the tag and
* the object to which the tag submits data."
*/
public void setDataSource(String dataSource)
{
_dataSource = dataSource;
}
/**
* Return an <code>ArrayList</code> which represents a chain of <code>INameInterceptor</code>
* objects. This method by default returns <code>null</code> and should be overridden
* by objects that support naming.
* @return an <code>ArrayList</code> that will contain <code>INameInterceptor</code> objects.
*/
protected List getNamingChain()
{
return AbstractClassicTag.DefaultNamingChain;
}
/**
* Return the Object that is represented by the specified data source.
* @return Object
* @throws JspException
*/
protected Object evaluateDataSource()
throws JspException
{
// @todo: at some point we need to switch the expression evaluation to not require '{'
ExpressionHandling expr = new ExpressionHandling(this);
String datasource = "{" + _dataSource + "}";
String ds = expr.ensureValidExpression(datasource, "dataSource", "DataSourceError");
if (ds == null)
return null;
// have a valid expression
return expr.evaluateExpression(datasource, "dataSource", pageContext);
}
/**
* This method will create the name of the form element (HTML Control) that has a name. The
* <b>name</b> attribute represent the "control name" for the control. This name is scoped
* into the form element. In addition, a control may have a <b>id</b> attribute which is
* specified by setting the <b>tagId</b>. These two value are set in this routine. The name
* is always the expression mapping the data to it's backing element and is conotrolled
* by the optional naming chain provided by the tag. The <b>tagId</b> specifies the <b>id</b>
* attribute. If this is present then we write out a JavaScript that allows mapping
* the tagId set on the tag to both the real <b>id</b> value and also the <b>name</b> value.
* The <b>id</b> is formed by passing the <b>tagId</b> to the URL rewritter service.
* @param state The tag state structure. This contains both the name and id attributes. The
* id attribute should be set with the initial value from the tagId.
* @param javaScript A ByRef element that will contain any JavaScript that should be written out
* by the calling tag. A value is returned only if tagId is set and there is not IScriptReporter
* found.
* @throws JspException Pass through the exception from applyNamingChain.
*/
protected void nameHtmlControl(AbstractHtmlControlState state, ByRef javaScript)
throws JspException
{
assert (javaScript != null) : "paramater 'javaScript' may not be null";
assert (state != null) : "parameter 'state' may not be null";
assert (_dataSource != null) : "dataSource is Null";
// create the expression (name)
String datasource = "{" + _dataSource + "}";
state.name = applyNamingChain(datasource);
Form parentForm = getNearestForm();
String idScript = renderNameAndId((HttpServletRequest) pageContext.getRequest(), state, parentForm);
if (idScript != null)
javaScript.setRef(idScript);
}
/**
* Release any acquired resources.
*/
protected void localRelease()
{
super.localRelease();
_dataSource = null;
}
}