package org.apache.velocity.app; /* * 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.Template; import org.apache.velocity.context.Context; import org.apache.velocity.exception.MethodInvocationException; import org.apache.velocity.exception.ParseErrorException; import org.apache.velocity.exception.ResourceNotFoundException; import org.apache.velocity.runtime.RuntimeConstants; import org.apache.velocity.runtime.RuntimeInstance; import org.slf4j.Logger; import java.io.Reader; import java.io.Writer; import java.util.Properties; /** *
* This class provides a separate new-able instance of the * Velocity template engine. The alternative model for use * is using the Velocity class which employs the singleton * model. *
*Velocity will call * the parameter-less init() at the first use of this class * if the init() wasn't explicitly called. While this will * ensure that Velocity functions, it probably won't * function in the way you intend, so it is strongly recommended that * you call an init() method yourself if you use the default constructor. *
* * @version $Id$ */ public class VelocityEngine implements RuntimeConstants { private RuntimeInstance ri = new RuntimeInstance(); /** * Init-less CTOR */ public VelocityEngine() { // do nothing } /** * Construct a VelocityEngine with the initial properties defined in the file * propsFilename * @param propsFilename properties filename */ public VelocityEngine(String propsFilename) { ri.setProperties(propsFilename); } /** * Construct a VelocityEngine instance with the specified initial properties. * @param p properties */ public VelocityEngine(Properties p) { ri.setProperties(p); } /** * initialize the Velocity runtime engine, using the default * properties of the Velocity distribution */ public void init() { ri.init(); } /** * Resets the instance, so Velocity can be re-initialized again. * * @since 2.0.0 */ public void reset() { ri.reset(); } /** * initialize the Velocity runtime engine, using default properties * plus the properties in the properties file passed in as the arg * * @param propsFilename file containing properties to use to initialize * the Velocity runtime */ public void init(String propsFilename) { ri.init(propsFilename); } /** * initialize the Velocity runtime engine, using default properties * plus the properties in the passed in java.util.Properties object * * @param p Properties object containing initialization properties */ public void init(Properties p) { ri.init(p); } /** * Set a Velocity Runtime property. * * @param key * @param value */ public void setProperty(String key, Object value) { ri.setProperty(key, value); } /** * Add a Velocity Runtime property. * * @param key * @param value */ public void addProperty(String key, Object value) { ri.addProperty(key, value); } /** * Clear a Velocity Runtime property. * * @param key of property to clear */ public void clearProperty(String key) { ri.clearProperty(key); } /** * Set an entire configuration at once from a Properties configuration * * @param configuration * @since 2.0 */ public void setProperties(Properties configuration) { ri.setProperties( configuration ); } /** * Set an entire configuration at once from a named properties file * * @param propsFilename properties filename * @since 2.1 */ public void setProperties(String propsFilename) { ri.setProperties(propsFilename); } /** * Get a Velocity Runtime property. * * @param key property to retrieve * @return property value or null if the property * not currently set */ public Object getProperty( String key ) { return ri.getProperty( key ); } /** * renders the input string using the context into the output writer. * To be used when a template is dynamically constructed, or want to use * Velocity as a token replacer. * * @param context context to use in rendering input string * @param out Writer in which to render the output * @param logTag string to be used as the template name for log * messages in case of error * @param instring input string containing the VTL to be rendered * * @return true if successful, false otherwise. If false, see * Velocity runtime log * @throws ParseErrorException The template could not be parsed. * @throws MethodInvocationException A method on a context object could not be invoked. * @throws ResourceNotFoundException A referenced resource could not be loaded. */ public boolean evaluate( Context context, Writer out, String logTag, String instring ) throws ParseErrorException, MethodInvocationException, ResourceNotFoundException { return ri.evaluate(context, out, logTag, instring); } /** * Renders the input reader using the context into the output writer. * To be used when a template is dynamically constructed, or want to * use Velocity as a token replacer. * * @param context context to use in rendering input string * @param writer Writer in which to render the output * @param logTag string to be used as the template name for log messages * in case of error * @param reader Reader containing the VTL to be rendered * * @return true if successful, false otherwise. If false, see * Velocity runtime log * @throws ParseErrorException The template could not be parsed. * @throws MethodInvocationException A method on a context object could not be invoked. * @throws ResourceNotFoundException A referenced resource could not be loaded. * @since Velocity v1.1 */ public boolean evaluate(Context context, Writer writer, String logTag, Reader reader) throws ParseErrorException, MethodInvocationException, ResourceNotFoundException { return ri.evaluate(context, writer, logTag, reader); } /** * Invokes a currently registered Velocimacro with the params provided * and places the rendered stream into the writer. *Template
from the Velocity
* resource management system.
*
* @param name The file name of the desired template.
* @return The template.
* @throws ResourceNotFoundException if template not found
* from any available source.
* @throws ParseErrorException if template cannot be parsed due
* to syntax (or other) error.
*/
public Template getTemplate(String name)
throws ResourceNotFoundException, ParseErrorException
{
return ri.getTemplate( name );
}
/**
* Returns a Template
from the Velocity
* resource management system.
*
* @param name The file name of the desired template.
* @param encoding The character encoding to use for the template.
* @return The template.
* @throws ResourceNotFoundException if template not found
* from any available source.
* @throws ParseErrorException if template cannot be parsed due
* to syntax (or other) error.
* @since Velocity v1.1
*/
public Template getTemplate(String name, String encoding)
throws ResourceNotFoundException, ParseErrorException
{
return ri.getTemplate( name, encoding );
}
/**
* Determines if a resource is accessible via the currently
* configured resource loaders.
* org.apache.velocity
* if it hasn't been configured using the property runtime.log.name
or the property
* runtime.log.instance
.
* @return A Logger object.
* @since 1.5
*/
public Logger getLog()
{
return ri.getLog();
}
/**
* * Sets an application attribute (which can be any Object) that will be * accessible from any component of the system that gets a * RuntimeServices. This allows communication between the application * environment and custom pluggable components of the Velocity engine, * such as ResourceLoaders and Loggers. *
* ** Note that there is no enforcement or rules for the key * used - it is up to the application developer. However, to * help make the intermixing of components possible, using * the target Class name (e.g. com.foo.bar ) as the key * might help avoid collision. *
* * @param key object 'name' under which the object is stored * @param value object to store under this key */ public void setApplicationAttribute( Object key, Object value ) { ri.setApplicationAttribute(key, value); } /** ** Return an application attribute (which can be any Object) * that was set by the application in order to be accessible from * any component of the system that gets a RuntimeServices. * This allows communication between the application * environment and custom pluggable components of the * Velocity engine, such as ResourceLoaders and Loggers. *
* * @param key object 'name' under which the object is stored * @return value object to store under this key * @since 1.5 */ public Object getApplicationAttribute( Object key ) { return ri.getApplicationAttribute(key); } /** * Remove a directive. * @param name name of the directive. */ public void removeDirective(String name) { ri.removeDirective(name); } /** * Instantiates and loads the directive with some basic checks. * * @param directiveClass classname of directive to load */ public void loadDirective(String directiveClass) { ri.loadDirective(directiveClass); } }