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package org.apache.velocity;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.apache.velocity.context.Context;
import org.apache.velocity.context.InternalContextAdapterImpl;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.exception.VelocityException;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.directive.Scope;
import org.apache.velocity.runtime.directive.StopCommand;
import org.apache.velocity.runtime.parser.ParseException;
import org.apache.velocity.runtime.parser.node.SimpleNode;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.runtime.resource.ResourceManager;
import org.slf4j.Logger;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * This class is used for controlling all template
 * operations. This class uses a parser created
 * by JavaCC to create an AST that is subsequently
 * traversed by a Visitor.
 *
 * 
 * // set up and initialize Velocity before this code block
 *
 * Template template = Velocity.getTemplate("test.wm");
 * Context context = new VelocityContext();
 *
 * context.put("foo", "bar");
 * context.put("customer", new Customer());
 *
 * template.merge(context, writer);
 * 
* * @author Jason van Zyl * @author Geir Magnusson Jr. * @version $Id: Template.java 1783725 2017-02-20 08:41:00Z cbrisson $ */ public class Template extends Resource { /* * The name of the variable to use when placing * the scope object into the context. */ private String scopeName = "template"; private boolean provideScope = false; private Map macros = new ConcurrentHashMap(17, 0.7f); private VelocityException errorCondition = null; /** Default constructor */ public Template() { super(); setType(ResourceManager.RESOURCE_TEMPLATE); } /** * get the map of all macros defined by this template * @return macros map */ public Map getMacros() { return macros; } /** * gets the named resource as a stream, parses and inits * * @return true if successful * @throws ResourceNotFoundException if template not found * from any available source. * @throws ParseErrorException if template cannot be parsed due * to syntax (or other) error. * @throws IOException problem reading input stream */ public boolean process() throws ResourceNotFoundException, ParseErrorException { data = null; Reader reader = null; errorCondition = null; /* * first, try to get the stream from the loader */ try { reader = resourceLoader.getResourceReader(name, getEncoding()); } catch( ResourceNotFoundException rnfe ) { /* * remember and re-throw */ errorCondition = rnfe; throw rnfe; } /* * if that worked, lets protect in case a loader impl * forgets to throw a proper exception */ if (reader != null) { /* * now parse the template */ try { BufferedReader br = new BufferedReader( reader ); data = rsvc.parse( br, this); initDocument(); return true; } catch ( ParseException pex ) { /* * remember the error and convert */ errorCondition = new ParseErrorException(pex, name); throw errorCondition; } catch ( TemplateInitException pex ) { errorCondition = new ParseErrorException( pex, name); throw errorCondition; } /** * pass through runtime exceptions */ catch( RuntimeException e ) { errorCondition = new VelocityException("Exception thrown processing Template " +getName(), e); throw errorCondition; } finally { /* * Make sure to close the inputstream when we are done. */ try { reader.close(); } catch(IOException e) { // If we are already throwing an exception then we want the original // exception to be continued to be thrown, otherwise, throw a new Exception. if (errorCondition == null) { throw new VelocityException(e); } } } } else { /* * is == null, therefore we have some kind of file issue */ errorCondition = new ResourceNotFoundException("Unknown resource error for resource " + name ); throw errorCondition; } } /** * initializes the document. init() is not longer * dependant upon context, but we need to let the * init() carry the template name down through for VM * namespace features * @throws TemplateInitException When a problem occurs during the document initialization. */ public void initDocument() throws TemplateInitException { /* * send an empty InternalContextAdapter down into the AST to initialize it */ InternalContextAdapterImpl ica = new InternalContextAdapterImpl( new VelocityContext() ); try { /* * put the current template name on the stack */ ica.pushCurrentTemplateName( name ); ica.setCurrentResource( this ); /* * init the AST */ ((SimpleNode)data).init( ica, rsvc); String property = scopeName+'.'+RuntimeConstants.PROVIDE_SCOPE_CONTROL; provideScope = rsvc.getBoolean(property, provideScope); } finally { /* * in case something blows up... * pull it off for completeness */ ica.popCurrentTemplateName(); ica.setCurrentResource( null ); } } /** * The AST node structure is merged with the * context to produce the final output. * * @param context Context with data elements accessed by template * @param writer output writer for rendered template * @throws ResourceNotFoundException if template not found * from any available source. * @throws ParseErrorException if template cannot be parsed due * to syntax (or other) error. * @throws MethodInvocationException When a method on a referenced object in the context could not invoked. */ public void merge( Context context, Writer writer) throws ResourceNotFoundException, ParseErrorException, MethodInvocationException { merge(context, writer, null); } /** * The AST node structure is merged with the * context to produce the final output. * * @param context Context with data elements accessed by template * @param writer output writer for rendered template * @param macroLibraries a list of template files containing macros to be used when merging * @throws ResourceNotFoundException if template not found * from any available source. * @throws ParseErrorException if template cannot be parsed due * to syntax (or other) error. * @throws MethodInvocationException When a method on a referenced object in the context could not invoked. * @since 1.6 */ public void merge( Context context, Writer writer, List macroLibraries) throws ResourceNotFoundException, ParseErrorException, MethodInvocationException { /* * 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 libTemplates = new ArrayList(); ica.setMacroLibraries(libTemplates); if (macroLibraries != null) { for (String macroLibrary : (List)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 " + (String) 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); } 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); } } }




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