Automatic compilation of subreports with JasperReports

JasperReportBuilder.java

package br.com.triadworks.controller.relatorios.jasper;

import java.io.ByteArrayOutputStream;
import java.sql.Connection;
import java.util.Map;
import javax.sql.DataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRExporter;
import net.sf.jasperreports.engine.JRExporterParameter;
import net.sf.jasperreports.engine.JasperCompileManager;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.engine.JasperReport;
import net.sf.jasperreports.engine.export.JRPdfExporter;
import net.sf.jasperreports.engine.util.JRElementsVisitor;
import org.springframework.jdbc.datasource.DataSourceUtils;
import br.com.syspdv.exceptions.RelatorioNaoGeradoException;

public class JasperReportBuilder {
	
	private final DataSource dataSource;
	
	public JasperReportBuilder(DataSource dataSource) {
		this.dataSource = dataSource;
	}

	public byte[] build(String jrxmlFile, Map<String, Object> parameters) {
		try {
			JasperPrint print = compileAndFillReport(jrxmlFile, parameters);
			byte[] content = exportToPdf(print);
			return content;
		} catch (Exception e) {
			throw new RelatorioNaoGeradoException(e.getMessage(), e);
		}
	}
	
	private JasperPrint compileAndFillReport(String jrxmlFile, Map<String, Object> parametros) throws JRException {
		
		JasperReport report = JasperCompileManager.compileReport(jrxmlFile);
		JRElementsVisitor.visitReport(report, new SubReportVisitor("/repositorio/de/jaspers/")); // the magic is here!
		
		JasperPrint print = fillReport(parametros, report);
		return print;
	}

	private byte[] exportToPdf(JasperPrint print) throws JRException {
		JRExporter exporter = new JRPdfExporter();

		ByteArrayOutputStream exported = new ByteArrayOutputStream();
		
		exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, exported);
		exporter.setParameter(JRExporterParameter.JASPER_PRINT, print);
		
		exporter.exportReport();
		
		return exported.toByteArray();
	}
	
	private JasperPrint fillReport(Map<String, Object> parametros, JasperReport report) throws JRException {
		Connection connection = null;
		try {
			connection = getConnection();
			return JasperFillManager.fillReport(report, parametros, connection);
		} finally {
			DataSourceUtils.releaseConnection(connection, dataSource);
		}
	}
	
	private Connection getConnection() {
		try {
			return DataSourceUtils.getConnection(dataSource);
		} catch (Exception e) {
			throw new IllegalStateException("Impossivel obter uma conexão com o banco de dados.", e);
		}
	}
	
}

SubReportInfo.java

package br.com.triadworks.controller.relatorios.jasper;

import java.io.File;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import net.sf.jasperreports.engine.JRSubreport;

public class SubReportInfo {
	
	private final static Pattern FILENAME_PATTERN = Pattern.compile("\"(.*?.jasper)");

	private final File sourceSubreport;
	private final File compiledSubreport;

	public SubReportInfo(JRSubreport subreport, String jasperPath) {
		String filename = extractFilename(subreport);
		this.compiledSubreport = new File(jasperPath, filename);
		this.sourceSubreport = new File(jasperPath, filename.replaceAll(".jasper", ".jrxml"));
	}
	
	public String getJRXMLFilename() {
		return sourceSubreport.getName();
	}
	
	public String getJRXMLFilepath() {
		return sourceSubreport.getAbsolutePath();
	}

	public boolean shouldCompile() {
		if (!compiledSubreport.exists()) return true;
		return (compiledSubreport.lastModified() < sourceSubreport.lastModified());
	}

	public String extractFilename(JRSubreport subreport) {
		String expression = subreport.getExpression().getText();
		Matcher matcher = FILENAME_PATTERN.matcher(expression);
		if (matcher.find()) {
			if (matcher.groupCount() > 0) {
				return matcher.group(1);
			}
		}
		throw new IllegalStateException("Não foi possível obter o nome do subrelatório da expressão '" + expression +"'." );
	}
	
}

SubReportVisitor.java

package br.com.triadworks.controller.relatorios.jasper;

import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRSubreport;
import net.sf.jasperreports.engine.JasperCompileManager;
import net.sf.jasperreports.engine.util.JRVisitorSupport;

public class SubReportVisitor extends JRVisitorSupport {

	private final String jasperPath;

	public SubReportVisitor(String jasperPath) {
		this.jasperPath = jasperPath;
	}
	
	@Override
	public void visitSubreport(JRSubreport subreport) {
	    SubReportInfo subReportInfo = new SubReportInfo(subreport, jasperPath);
	    compile(subReportInfo);
	}

	private void compile(SubReportInfo subReportInfo) {
	    try {
	    	
	    	if (subReportInfo.shouldCompile())
	    		JasperCompileManager.compileReportToFile(subReportInfo.getJRXMLFilepath());
	    	
	    } catch (JRException e) {
	    	throw new IllegalStateException("Não foi possível compilar o subrelatório '" + subReportInfo.getJRXMLFilename() + "'.", e);
	    }
	}
	
}

TestingJasperReportBuilder.java

public class TestingJasperReportBuilder {

  public static void main(String[] args) {
		
		DataSource dataSource = DataSourceFactory.default(); // your datasource
		Map<String, Object> parameters = new HashMap<String, Object>();
		
		JasperReportBuilder builder = new JasperReportBuilder(dataSource);
		byte[] bytes = builder.build("report.jrxml", parameters);
		
	}
	
}