org.apache.struts2.views.jsp.iterator.IteratorGeneratorTag Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.struts2.views.jsp.iterator;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.struts2.util.IteratorGenerator;
import org.apache.struts2.util.IteratorGenerator.Converter;
import org.apache.struts2.views.annotations.StrutsTag;
import org.apache.struts2.views.annotations.StrutsTagAttribute;
import org.apache.struts2.views.jsp.StrutsBodyTagSupport;
import javax.servlet.jsp.JspException;
/**
*
* NOTE: JSP-TAG
*
* Generate an iterator based on the val attribute supplied.
*
* NOTE: The generated iterator will ALWAYS be pushed into the top of the stack, and poped
* at the end of the tag.
*
*
*
*
* - val* (Object) - the source to be parsed into an iterator
* - count (Object) - the max number (Integer, Float, Double, Long, String) entries to be in the iterator
* - separator (String) - the separator to be used in separating the val into entries of the iterator
* - var (String) - the name to store the resultant iterator into page context, if such name is supplied
* - converter (Object) - the converter (must extends off IteratorGenerator.Converter interface) to convert the String entry parsed from val into an object
*
*
*
*
*
* Example One:
*
* Generate a simple iterator
* <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}">
* <s:iterator>
* <s:property /><br/>
* </s:iterator>
* </s:generator>
*
* This generates an iterator and print it out using the iterator tag.
*
* Example Two:
*
* Generate an iterator with count attribute
* <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}" count="3">
* <s:iterator>
* <s:property /><br/>
* </s:iterator>
* </s:generator>
*
* This generates an iterator, but only 3 entries will be available in the iterator
* generated, namely aaa, bbb and ccc respectively because count attribute is set to 3
*
* Example Three:
*
* Generate an iterator with var attribute
* <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}" count="4" separator="," var="myAtt" />
* <%
* Iterator i = (Iterator) pageContext.getAttribute("myAtt");
* while(i.hasNext()) {
* String s = (String) i.next(); %>
* <%=s%> <br/>
* <% }
* %>
*
* This generates an iterator and put it in the PageContext under the key as specified
* by the var attribute.
*
*
* Example Four:
*
* Generate an iterator with comparator attribute
* <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}" converter="%{myConverter}">
* <s:iterator>
* <s:property /><br/>
* </s:iterator>
* </s:generator>
*
*
* public class GeneratorTagAction extends ActionSupport {
*
* ....
*
* public Converter getMyConverter() {
* return new Converter() {
* public Object convert(String value) throws Exception {
* return "converter-"+value;
* }
* };
* }
*
* ...
*
* }
*
* This will generate an iterator with each entries decided by the converter supplied. With
* this converter, it simply add "converter-" to each entries.
*
*
* @see org.apache.struts2.util.IteratorGenerator
*/
@StrutsTag(name="generator", tldTagClass="org.apache.struts2.views.jsp.iterator.IteratorGeneratorTag",
description="Generate an iterator for a iterable source.")
public class IteratorGeneratorTag extends StrutsBodyTagSupport {
private static final long serialVersionUID = 2968037295463973936L;
public static final String DEFAULT_SEPARATOR = ",";
private static final Logger LOG = LogManager.getLogger(IteratorGeneratorTag.class);
String countAttr;
String separatorAttr;
String valueAttr;
String converterAttr;
String var;
IteratorGenerator iteratorGenerator = null;
@StrutsTagAttribute(type="Integer",description="The max number entries to be in the iterator")
public void setCount(String count) {
countAttr = count;
}
/**
* {@literal @}s.tagattribute required="true" type="String"
* description="the separator to be used in separating the val into entries of the iterator"
*
* @param separator the seperator
*/
@StrutsTagAttribute(required=true, description="The separator to be used in separating the val into entries of the iterator")
public void setSeparator(String separator) {
separatorAttr = separator;
}
/**
* {@literal @}s.tagattribute required="true"
* description="the source to be parsed into an iterator"
*
* @param val the value
*/
@StrutsTagAttribute(required=true, description="The source to be parsed into an iterator")
public void setVal(String val) {
valueAttr = val;
}
@StrutsTagAttribute(type="org.apache.struts2.util.IteratorGenerator.Converter",
description="The converter to convert the String entry parsed from val into an object")
public void setConverter(String aConverter) {
converterAttr = aConverter;
}
@StrutsTagAttribute(description="The name to store the resultant iterator into page context, if such name is supplied")
public void setVar(String var) {
this.var = var;
}
public int doStartTag() throws JspException {
// value
Object value = findValue(valueAttr);
// separator
String separator = DEFAULT_SEPARATOR;
if (separatorAttr != null && separatorAttr.length() > 0) {
separator = findString(separatorAttr);
}
// TODO: maybe this could be put into an Util class, or there is already one?
// count
int count = 0;
if (countAttr != null && countAttr.length() > 0) {
Object countObj = findValue(countAttr);
if (countObj instanceof Number) {
count = ((Number)countObj).intValue();
}
else if (countObj instanceof String) {
try {
count = Integer.parseInt((String)countObj);
}
catch(NumberFormatException e) {
LOG.warn("Unable to convert count attribute [{}] to number, ignore count attribute", countObj, e);
}
}
}
// converter
Converter converter = null;
if (converterAttr != null && converterAttr.length() > 0) {
converter = (Converter) findValue(converterAttr);
}
iteratorGenerator = new IteratorGenerator();
iteratorGenerator.setValues(value);
iteratorGenerator.setCount(count);
iteratorGenerator.setSeparator(separator);
iteratorGenerator.setConverter(converter);
iteratorGenerator.execute();
// Push resulting iterator on stack and put into
// stack context if we have a "var" specified.
getStack().push(iteratorGenerator);
if (var != null && var.length() > 0) {
getStack().getContext().put(var, iteratorGenerator);
}
return EVAL_BODY_INCLUDE;
}
public int doEndTag() throws JspException {
// pop resulting iterator from stack at end tag
getStack().pop();
iteratorGenerator = null; // clean up
return EVAL_PAGE;
}
}