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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.JspException;
import jakarta.servlet.jsp.PageContext;
import jakarta.servlet.jsp.tagext.TagSupport;
import org.apache.taglibs.standard.tag.common.core.Util;
/**
* Tag handler for <set> in JSTL's XML library.
*
* @author Shawn Bayern
*/
public class SetTag extends TagSupport {
//*********************************************************************
// Internal state
private String select; // tag attribute
private String var; // tag attribute
private int scope; // processed tag attribute
//*********************************************************************
// Construction and initialization
/**
* Constructs a new handler. As with TagSupport, subclasses should
* not provide other constructors and are expected to call the
* superclass constructor.
*/
public SetTag() {
super();
init();
}
// resets local state
private void init() {
var = null;
select = null;
scope = PageContext.PAGE_SCOPE;
}
//*********************************************************************
// Tag logic
// applies XPath expression from 'select' and stores the result in 'var'
public int doStartTag() throws JspException {
// process the query
XPathUtil xu = new XPathUtil(pageContext);
List result =
xu.selectNodes(XPathUtil.getContext(this), select);
Object ret = result;
// unwrap primitive types if that's what we received
if (result.size() == 1) {
Object o = result.get(0);
if (o instanceof String || o instanceof Boolean
|| o instanceof Number)
ret = o;
}
// expose the final result
pageContext.setAttribute(var, ret, scope);
return SKIP_BODY;
}
// Releases any resources we may have (or inherit)
public void release() {
super.release();
init();
}
//*********************************************************************
// Attribute accessors
public void setSelect(String select) {
this.select = select;
}
public void setVar(String var) {
this.var = var;
}
public void setScope(String scope) {
this.scope = Util.getScope(scope);
}
}