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Free Java Reporting Library
/*
* JasperReports - Free Java Reporting Library.
* Copyright (C) 2001 - 2023 Cloud Software Group, Inc. All rights reserved.
* http://www.jaspersoft.com
*
* Unless you have purchased a commercial license agreement from Jaspersoft,
* the following license terms apply:
*
* This program is part of JasperReports.
*
* JasperReports is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JasperReports is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with JasperReports. If not, see .
*/
package net.sf.jasperreports.engine.fill;
import net.sf.jasperreports.engine.JRExpression;
import net.sf.jasperreports.engine.JRExpressionChunk;
import net.sf.jasperreports.engine.JRRuntimeException;
import net.sf.jasperreports.engine.type.ExpressionTypeEnum;
import net.sf.jasperreports.engine.util.ExpressionParser;
/**
*
* @author Lucian Chirita ([email protected])
*/
public class SimpleTextExpressionEvaluator
{
private static final String EMPTY_RESULT = "";
public static String evaluateExpression(JRExpression expression, ExpressionValues values)
{
if (expression.getType() != ExpressionTypeEnum.SIMPLE_TEXT)
{
throw new IllegalArgumentException("Simple text expression expected");
}
JRExpressionChunk[] chunks = expression.getChunks();
return evaluate(chunks, values);
}
public static String evaluate(JRExpressionChunk[] chunks, ExpressionValues values)
{
if (chunks == null || chunks.length == 0)
{
return EMPTY_RESULT;
}
ResultCollector result = new ResultCollector(values);
result.collectChunks(chunks);
return result.getResult();
}
private static class ResultCollector implements ExpressionParser.ParseResult
{
private final ExpressionValues values;
//keeping the first text separately to avoid creating a StringBuilder when there's a single chunk
private String firstText;
private StringBuilder resultBuilder;
public ResultCollector(ExpressionValues values)
{
this.values = values;
}
public String getResult()
{
String result;
if (resultBuilder != null)
{
result = resultBuilder.toString();
}
else if (firstText != null)
{
result = firstText;
}
else
{
result = EMPTY_RESULT;
}
return result;
}
private void appendText(String text)
{
assert text != null;
if (resultBuilder == null)
{
if (firstText == null)
{
firstText = text;
}
else
{
resultBuilder = new StringBuilder(firstText.length() + text.length() + 16);
resultBuilder.append(firstText);
resultBuilder.append(text);
firstText = null;
}
}
else
{
resultBuilder.append(text);
}
}
public void collectChunks(JRExpressionChunk[] chunks)
{
for (JRExpressionChunk chunk : chunks)
{
byte chunkType = chunk.getType();
if (chunkType == JRExpressionChunk.TYPE_TEXT)
{
appendTextChunk(chunk.getText());
}
else
{
appendValueChunk(chunkType, chunk.getText());
}
}
}
private void appendTextChunk(String text)
{
if (text != null)
{
appendText(text);
}
}
private void appendValueChunk(byte chunkType, String chunkText)
{
switch (chunkType)
{
case JRExpressionChunk.TYPE_RESOURCE:
appendValueChunk(values.getMessage(chunkText));
break;
case JRExpressionChunk.TYPE_PARAMETER:
appendValueChunk(values.getParameterValue(chunkText));
break;
case JRExpressionChunk.TYPE_FIELD:
appendValueChunk(values.getFieldValue(chunkText));
break;
case JRExpressionChunk.TYPE_VARIABLE:
appendValueChunk(values.getVariableValue(chunkText));
break;
default:
throw new JRRuntimeException("Unexpected expression chunk type " + chunkType);
}
}
private void appendValueChunk(Object value)
{
if (value == null)
{
appendText(String.valueOf(value));
}
else if (value instanceof String)
{
String text = (String) value;
ExpressionParser expressionParser = ExpressionParser.instance();
//fast test to determine whether the text could have further placeholders
if (expressionParser.fastPlaceholderDetect(text))
{
//could have placehoders, parsing and recursing
//TODO detect circular references?
expressionParser.parseExpression(text, this);
}
else
{
//no placehoders
appendText(text);
}
}
else
{
//no formatting for now
String text = String.valueOf(value);
appendText(text == null ? String.valueOf(text) : text);
}
}
@Override
public void addTextChunk(String text)
{
appendTextChunk(text);
}
@Override
public void addChunk(byte chunkType, String chunkText)
{
appendValueChunk(chunkType, chunkText);
}
}
}