Class MergeIterator
- All Implemented Interfaces:
Param.UnnamedParametric
Component for MergeIteratorTag, which job is to merge iterators and successive call to the merged iterator will cause each merge iterator to have a chance to expose its element, subsequently next call will allow the next iterator to expose its element. Once the last iterator is done exposing its element, the first iterator is allowed to do so again (unless it is exhausted of entries).
Internally the task are delegated to MergeIteratorFilter
Example if there are 3 lists being merged, each list have 3 entries, the following will be the logic.
- Display first element of the first list
- Display first element of the second list
- Display first element of the third list
- Display second element of the first list
- Display second element of the second list
- Display second element of the third list
- Display third element of the first list
- Display thrid element of the second list
- Display third element of the thrid list
- var (String) - the name where the resultant merged iterator will be stored in the stack's context
public class MergeIteratorTagAction extends ActionSupport {
private List myList1; private List myList2; private List myList3;
public List getMyList1() { return myList1; }
public List getMyList2() { return myList2; }
public List getMyList3() { return myList3; }
public String execute() throws Exception {
myList1 = new ArrayList(); myList1.add("1"); myList1.add("2"); myList1.add("3");
myList2 = new ArrayList(); myList2.add("a"); myList2.add("b"); myList2.add("c");
myList3 = new ArrayList(); myList3.add("A"); myList3.add("B"); myList3.add("C");
return "done"; } }
<s:merge var="myMergedIterator1"> <s:param value="%{myList1}" /> <s:param value="%{myList2}" /> <s:param value="%{myList3}" /> </s:merge> <s:iterator value="%{#myMergedIterator1}"> <s:property /> </s:iterator>
This wil generate "1aA2bB3cC".
- See Also:
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Field Summary
Fields inherited from class org.apache.struts2.components.ContextBean
varFields inherited from class org.apache.struts2.components.Component
actionMapper, attributes, COMPONENT_STACK, devMode, escapeHtmlBody, performClearTagStateForTagPoolingServers, stack, standardAttributesMap, throwExceptionOnELFailure -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoidaddParameter(Object value) Adds the given value as a parameter to the outer tag.booleanCallback for the end tag of this component.voidbooleanCallback for the start tag of this component.Methods inherited from class org.apache.struts2.components.ContextBean
getVar, putInContextMethods inherited from class org.apache.struts2.components.Component
addAllAttributes, addParameter, completeExpression, copyAttributes, determineActionURL, determineNamespace, end, escapeHtmlBody, fieldError, findAncestor, findString, findString, findValue, findValue, findValue, getAttributes, getComponentStack, getNamespace, getPerformClearTagStateForTagPoolingServers, getStack, getStandardAttributes, isAcceptableExpression, isValidTagAttribute, popComponentStack, setActionMapper, setDevMode, setEscapeHtmlBody, setNotExcludedAcceptedPatterns, setPerformClearTagStateForTagPoolingServers, setThrowExceptionsOnELFailure, setUrlHelper, stripExpression, toString, usesBody
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Constructor Details
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MergeIterator
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Method Details
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start
Description copied from class:ComponentCallback for the start tag of this component. Should the body be evaluated? -
end
Description copied from class:ComponentCallback for the end tag of this component. Should the body be evaluated again?
NOTE: will pop component stack. -
setVar
- Overrides:
setVarin classContextBean
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addParameter
Description copied from interface:Param.UnnamedParametricAdds the given value as a parameter to the outer tag.- Specified by:
addParameterin interfaceParam.UnnamedParametric- Parameters:
value- the value
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