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Jakarta Standard Tag Library Implementation
/*
* Copyright (c) 1997-2020 Oracle and/or its affiliates. All rights reserved.
* 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.
*/
package org.apache.taglibs.standard.tag.common.xml;
import java.util.List;
import jakarta.servlet.jsp.JspTagException;
import jakarta.servlet.jsp.jstl.core.LoopTagSupport;
import org.apache.taglibs.standard.resources.Resources;
/**
* Support for the XML library's <forEach> tag.
*
* @see jakarta.servlet.jsp.jstl.core.LoopTagSupport
* @author Shawn Bayern
*/
public class ForEachTag extends LoopTagSupport {
//*********************************************************************
// Private state
private String select; // tag attribute
private List nodes; // XPath result
private int nodesIndex; // current index
private org.w3c.dom.Node current; // current node
//*********************************************************************
// Iteration control methods
// (We inherit semantics and Javadoc from LoopTagSupport.)
protected void prepare() throws JspTagException {
nodesIndex = 0;
XPathUtil xu = new XPathUtil(pageContext);
nodes = xu.selectNodes(XPathUtil.getContext(this), select);
}
protected boolean hasNext() throws JspTagException {
return (nodesIndex < nodes.size());
}
protected Object next() throws JspTagException {
Object o = nodes.get(nodesIndex++);
if (!(o instanceof org.w3c.dom.Node))
throw new JspTagException(
Resources.getMessage("FOREACH_NOT_NODESET"));
current = (org.w3c.dom.Node) o;
return current;
}
//*********************************************************************
// Tag logic and lifecycle management
// Releases any resources we may have (or inherit)
public void release() {
init();
super.release();
}
//*********************************************************************
// Attribute accessors
public void setSelect(String select) {
this.select = select;
}
public void setBegin(int begin) throws JspTagException {
this.beginSpecified = true;
this.begin = begin;
validateBegin();
}
public void setEnd(int end) throws JspTagException {
this.endSpecified = true;
this.end = end;
validateEnd();
}
public void setStep(int step) throws JspTagException {
this.stepSpecified = true;
this.step = step;
validateStep();
}
//*********************************************************************
// Public methods for subtags
/* Retrieves the current context. */
public org.w3c.dom.Node getContext() throws JspTagException {
// expose the current node as the context
return current;
}
//*********************************************************************
// Private utility methods
private void init() {
select = null;
nodes = null;
nodesIndex = 0;
current = null;
}
}