public void merge()

in velocity-engine-core/src/main/java/org/apache/velocity/Template.java [280:435]
116 lines of code
19 McCabe index (conditional complexity)

    public void merge( Context context, Writer writer, List<String> macroLibraries)
        throws ResourceNotFoundException, ParseErrorException, MethodInvocationException
    {
        try
        {
            /*
             *  we shouldn't have to do this, as if there is an error condition,
             *  the application code should never get a reference to the
             *  Template
             */

            if (errorCondition != null)
            {
                throw errorCondition;
            }

            if (data != null)
            {
                /*
                 *  create an InternalContextAdapter to carry the user Context down
                 *  into the rendering engine.  Set the template name and render()
                 */

                InternalContextAdapterImpl ica = new InternalContextAdapterImpl(context);

                /*
                 * Set the macro libraries
                 */
                List<Template> libTemplates = new ArrayList<>();
                ica.setMacroLibraries(libTemplates);

                if (macroLibraries != null)
                {
                    for (String macroLibrary : macroLibraries)
                    {
                        /*
                         * Build the macro library
                         */
                        try
                        {
                            Template t = rsvc.getTemplate(macroLibrary);
                            libTemplates.add(t);
                        }
                        catch (ResourceNotFoundException re)
                        {
                            /*
                             * the macro lib wasn't found.  Note it and throw
                             */
                            log.error("cannot find template {}", macroLibrary);
                            throw re;
                        }
                        catch (ParseErrorException pe)
                        {
                            /*
                             * the macro lib was found, but didn't parse - syntax error
                             *  note it and throw
                             */
                            rsvc.getLog("parser").error("syntax error in template {}: {}",
                                macroLibrary, pe.getMessage(), pe);
                            throw pe;
                        }
                        catch (Exception e)
                        {
                            throw new RuntimeException("parse failed in template  " +
                                macroLibrary + ".", e);
                        }
                    }
                }

                if (provideScope)
                {
                    ica.put(scopeName, new Scope(this, ica.get(scopeName)));
                }
                try
                {
                    ica.pushCurrentTemplateName(name);
                    ica.setCurrentResource(this);

                    ((SimpleNode) data).render(ica, writer);
                }
                catch (StopCommand stop)
                {
                    if (!stop.isFor(this))
                    {
                        throw stop;
                    }
                    else
                    {
                        Logger renderingLog = rsvc.getLog("rendering");
                        renderingLog.debug(stop.getMessage());
                    }
                }
                catch (IOException e)
                {
                    throw new VelocityException("IO Error rendering template '" + name + "'", e, rsvc.getLogContext().getStackTrace());
                }
                finally
                {
                    /*
                     *  lets make sure that we always clean up the context
                     */
                    ica.popCurrentTemplateName();
                    ica.setCurrentResource(null);

                    if (provideScope)
                    {
                        Object obj = ica.get(scopeName);
                        if (obj instanceof Scope)
                        {
                            Scope scope = (Scope) obj;
                            if (scope.getParent() != null)
                            {
                                ica.put(scopeName, scope.getParent());
                            }
                            else if (scope.getReplaced() != null)
                            {
                                ica.put(scopeName, scope.getReplaced());
                            }
                            else
                            {
                                ica.remove(scopeName);
                            }
                        }
                    }
                }
            }
            else
            {
                /*
                 * this shouldn't happen either, but just in case.
                 */

                String msg = "Template merging failed. The document is null, " +
                    "most likely due to a parsing error.";

                throw new RuntimeException(msg);

            }
        }
        catch (VelocityException ve)
        {
            /* it's a good place to display the VTL stack trace if we have one */
            String[] vtlStacktrace = ve.getVtlStackTrace();
            if (vtlStacktrace != null)
            {
                Logger renderingLog = rsvc.getLog("rendering");
                renderingLog.error(ve.getMessage());
                renderingLog.error("VTL stacktrace:");
                for (String level : vtlStacktrace)
                {
                    renderingLog.error(level);
                }
            }
            throw ve;
        }
    }