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package org.apache.taglibs.standard.tag.common.core;
import java.util.StringTokenizer;
import javax.el.ValueExpression;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.jstl.core.LoopTagSupport;
import org.apache.taglibs.standard.resources.Resources;
/**
* Support for tag handlers for <forTokens>, the tokenizing
* iteration tag in JSTL 1.0. This class extends LoopTagSupport and
* provides ForTokens-specific functionality. The rtexprvalue and
* expression-evaluating libraries each have handlers that extend this
* class.
*
* @see javax.servlet.jsp.jstl.core.LoopTagSupport
* @author Shawn Bayern
*/
public abstract class ForTokensSupport extends LoopTagSupport {
//*********************************************************************
// Implementation overview
/*
* This handler simply constructs a StringTokenizer based on its input
* and relays tokens to the iteration implementation that it inherits.
* The 'items' and 'delims' attributes are expected to be provided by
* a subtag (presumably in the rtexprvalue or expression-evaluating
* versions of the JSTL library).
*/
//*********************************************************************
// ForEachTokens-specific state (protected)
protected Object items; // 'items' attribute
protected String delims; // 'delims' attribute
protected StringTokenizer st; // digested tokenizer
//*********************************************************************
// Iteration control methods
/*
* These just create and use a StringTokenizer.
* We inherit semantics and Javadoc from LoopTagSupport.
*/
protected void prepare() throws JspTagException {
if (items instanceof ValueExpression) {
deferredExpression = (ValueExpression) items;
items = deferredExpression.getValue(pageContext.getELContext());
}
if (!(items instanceof String)) {
throw new JspTagException(
Resources.getMessage("FORTOKENS_BAD_ITEMS"));
}
st = new StringTokenizer((String)items, delims);
}
protected boolean hasNext() throws JspTagException {
return st.hasMoreElements();
}
protected Object next() throws JspTagException {
return st.nextElement();
}
protected String getDelims() {
return delims;
}
//*********************************************************************
// Tag logic and lifecycle management
// Releases any resources we may have (or inherit)
public void release() {
super.release();
items = delims = null;
st = null;
deferredExpression = null;
}
}