org.apache.taglibs.standard.lang.jstl.ExpressionString Maven / Gradle / Ivy
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package org.apache.taglibs.standard.lang.jstl;
import java.util.Map;
/**
*
* Represents an expression String consisting of a mixture of
* Strings and Expressions.
*
* @author Nathan Abramson - Art Technology Group
* @author Shawn Bayern
* @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: kchung $
**/
public class ExpressionString
{
//-------------------------------------
// Properties
//-------------------------------------
// property elements
Object [] mElements;
public Object [] getElements ()
{ return mElements; }
public void setElements (Object [] pElements)
{ mElements = pElements; }
//-------------------------------------
/**
*
* Constructor
**/
public ExpressionString (Object [] pElements)
{
mElements = pElements;
}
//-------------------------------------
/**
*
* Evaluates the expression string by evaluating each element,
* converting it to a String (using toString, or "" for null values)
* and concatenating the results into a single String.
**/
public String evaluate (Object pContext,
VariableResolver pResolver,
Map functions,
String defaultPrefix,
Logger pLogger)
throws ELException
{
StringBuffer buf = new StringBuffer ();
for (int i = 0; i < mElements.length; i++) {
Object elem = mElements [i];
if (elem instanceof String) {
buf.append ((String) elem);
}
else if (elem instanceof Expression) {
Object val =
((Expression) elem).evaluate (pContext,
pResolver,
functions,
defaultPrefix,
pLogger);
if (val != null) {
buf.append (val.toString ());
}
}
}
return buf.toString ();
}
//-------------------------------------
/**
*
* Returns the expression in the expression language syntax
**/
public String getExpressionString ()
{
StringBuffer buf = new StringBuffer ();
for (int i = 0; i < mElements.length; i++) {
Object elem = mElements [i];
if (elem instanceof String) {
buf.append ((String) elem);
}
else if (elem instanceof Expression) {
buf.append ("${");
buf.append (((Expression) elem).getExpressionString ());
buf.append ("}");
}
}
return buf.toString ();
}
//-------------------------------------
}