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package org.apache.velocity.runtime;

/*
 * 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 java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.util.Properties;

import org.apache.commons.collections.ExtendedProperties;
import org.apache.velocity.Template;
import org.apache.velocity.app.event.EventCartridge;
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.directive.Directive;
import org.apache.velocity.runtime.log.Log;
import org.apache.velocity.runtime.parser.ParseException;
import org.apache.velocity.runtime.parser.Parser;
import org.apache.velocity.runtime.parser.node.Node;
import org.apache.velocity.runtime.parser.node.SimpleNode;
import org.apache.velocity.runtime.resource.ContentResource;
import org.apache.velocity.util.introspection.Introspector;
import org.apache.velocity.util.introspection.Uberspect;


/**
 * Interface for internal runtime services that are needed by the
 * various components w/in Velocity.  This was taken from the old
 * Runtime singleton, and anything not necessary was removed.
 *
 *  Currently implemented by RuntimeInstance.
 *
 * @author Geir Magusson Jr.
 * @version $Id: RuntimeServices.java 685724 2008-08-13 23:12:12Z nbubna $
 */
public interface RuntimeServices extends RuntimeLogger
{

   /**
     * This is the primary initialization method in the Velocity
     * Runtime. The systems that are setup/initialized here are
     * as follows:
     *
     * 
    *
  • Logging System
  • *
  • ResourceManager
  • *
  • Parser Pool
  • *
  • Global Cache
  • *
  • Static Content Include System
  • *
  • Velocimacro System
  • *
* @throws Exception */ public void init() throws Exception; /** * Allows an external system to set a property in * the Velocity Runtime. * * @param key property key * @param value property value */ public void setProperty(String key, Object value); /** * Allow an external system to set an ExtendedProperties * object to use. This is useful where the external * system also uses the ExtendedProperties class and * the velocity configuration is a subset of * parent application's configuration. This is * the case with Turbine. * * @param configuration */ public void setConfiguration( ExtendedProperties configuration); /** * Add a property to the configuration. If it already * exists then the value stated here will be added * to the configuration entry. For example, if * * resource.loader = file * * is already present in the configuration and you * * addProperty("resource.loader", "classpath") * * Then you will end up with a Vector like the * following: * * ["file", "classpath"] * * @param key * @param value */ public void addProperty(String key, Object value); /** * Clear the values pertaining to a particular * property. * * @param key of property to clear */ public void clearProperty(String key); /** * Allows an external caller to get a property. The calling * routine is required to know the type, as this routine * will return an Object, as that is what properties can be. * * @param key property to return * @return The value. */ public Object getProperty( String key ); /** * Initialize the Velocity Runtime with a Properties * object. * * @param p * @throws Exception */ public void init(Properties p) throws Exception; /** * Initialize the Velocity Runtime with the name of * ExtendedProperties object. * * @param configurationFile * @throws Exception */ public void init(String configurationFile) throws Exception; /** * Wraps the String in a StringReader and passes it off to * {@link #parse(Reader,String)}. * @since 1.6 */ public SimpleNode parse(String string, String templateName) throws ParseException; /** * Parse the input and return the root of * AST node structure. *

* In the event that it runs out of parsers in the * pool, it will create and let them be GC'd * dynamically, logging that it has to do that. This * is considered an exceptional condition. It is * expected that the user will set the * PARSER_POOL_SIZE property appropriately for their * application. We will revisit this. * * @param reader inputstream retrieved by a resource loader * @param templateName name of the template being parsed * @return The AST representing the template. * @throws ParseException */ public SimpleNode parse( Reader reader, String templateName ) throws ParseException; /** * Parse the input and return the root of the AST node structure. * * @param reader inputstream retrieved by a resource loader * @param templateName name of the template being parsed * @param dumpNamespace flag to dump the Velocimacro namespace for this template * @return The AST representing the template. * @throws ParseException */ public SimpleNode parse( Reader reader, String templateName, boolean dumpNamespace ) throws ParseException; /** * 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. * @throws IOException While rendering to the writer, an I/O problem occured. * @since Velocity 1.6 */ public boolean evaluate(Context context, Writer out, String logTag, String instring) throws IOException; /** * 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. * @throws IOException While reading from the reader or rendering to the writer, * an I/O problem occured. * @since Velocity 1.6 */ public boolean evaluate(Context context, Writer writer, String logTag, Reader reader) throws IOException; /** * Invokes a currently registered Velocimacro with the params provided * and places the rendered stream into the writer. *
* Note : currently only accepts args to the VM if they are in the context. * * @param vmName name of Velocimacro to call * @param logTag string to be used for template name in case of error. if null, * the vmName will be used * @param params keys for args used to invoke Velocimacro, in java format * rather than VTL (eg "foo" or "bar" rather than "$foo" or "$bar") * @param context Context object containing data/objects used for rendering. * @param writer Writer for output stream * @return true if Velocimacro exists and successfully invoked, false otherwise. * @throws IOException While rendering to the writer, an I/O problem occured. * @since 1.6 */ public boolean invokeVelocimacro(final String vmName, String logTag, String[] params, final Context context, final Writer writer) throws IOException; /** * Returns a Template from the resource manager. * This method assumes that the character encoding of the * template is set by the input.encoding * property. The default is "ISO-8859-1" * * @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. * @throws Exception if an error occurs in template initialization */ public Template getTemplate(String name) throws ResourceNotFoundException, ParseErrorException, Exception; /** * Returns a Template from the resource manager * * @param name The name of the desired template. * @param encoding Character encoding of 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. * @throws Exception if an error occurs in template initialization */ public Template getTemplate(String name, String encoding) throws ResourceNotFoundException, ParseErrorException, Exception; /** * Returns a static content resource from the * resource manager. Uses the current value * if INPUT_ENCODING as the character encoding. * * @param name Name of content resource to get * @return parsed ContentResource object ready for use * @throws ResourceNotFoundException if template not found * from any available source. * @throws ParseErrorException * @throws Exception */ public ContentResource getContent(String name) throws ResourceNotFoundException, ParseErrorException, Exception; /** * Returns a static content resource from the * resource manager. * * @param name Name of content resource to get * @param encoding Character encoding to use * @return parsed ContentResource object ready for use * @throws ResourceNotFoundException if template not found * from any available source. * @throws ParseErrorException * @throws Exception */ public ContentResource getContent( String name, String encoding ) throws ResourceNotFoundException, ParseErrorException, Exception; /** * Determines is a template exists, and returns name of the loader that * provides it. This is a slightly less hokey way to support * the Velocity.templateExists() utility method, which was broken * when per-template encoding was introduced. We can revisit this. * * @param resourceName Name of template or content resource * @return class name of loader than can provide it */ public String getLoaderNameForResource( String resourceName ); /** * String property accessor method with default to hide the * configuration implementation. * * @param key property key * @param defaultValue default value to return if key not * found in resource manager. * @return String value of key or default */ public String getString( String key, String defaultValue); /** * Returns the appropriate VelocimacroProxy object if strVMname * is a valid current Velocimacro. * * @param vmName Name of velocimacro requested * @param templateName Name of the namespace. * @return VelocimacroProxy */ public Directive getVelocimacro( String vmName, String templateName ); /** * Returns the appropriate VelocimacroProxy object if strVMname * is a valid current Velocimacro. * * @param vmName Name of velocimacro requested * @param templateName Name of the namespace. * @param renderingTemplate Name of the template we are currently rendering. This * information is needed when VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL setting is true * and template contains a macro with the same name as the global macro library. * * @since Velocity 1.6 * * @return VelocimacroProxy */ public Directive getVelocimacro( String vmName, String templateName, String renderingTemplate ); /** * Adds a new Velocimacro. Usually called by Macro only while parsing. * * @param name Name of velocimacro * @param macro String form of macro body * @param argArray Array of strings, containing the * #macro() arguments. the 0th is the name. * @param sourceTemplate * * @deprecated Use addVelocimacro(String, Node, String[], String) instead * * @return boolean True if added, false if rejected for some * reason (either parameters or permission settings) */ public boolean addVelocimacro( String name, String macro, String argArray[], String sourceTemplate ); /** * Adds a new Velocimacro. Usually called by Macro only while parsing. * * @param name Name of velocimacro * @param macro root AST node of the parsed macro * @param argArray Array of strings, containing the * #macro() arguments. the 0th is the name. * @param sourceTemplate * * @since Velocity 1.6 * * @return boolean True if added, false if rejected for some * reason (either parameters or permission settings) */ public boolean addVelocimacro( String name, Node macro, String argArray[], String sourceTemplate ); /** * Checks to see if a VM exists * * @param vmName Name of velocimacro * @param templateName * @return boolean True if VM by that name exists, false if not */ public boolean isVelocimacro( String vmName, String templateName ); /** * tells the vmFactory to dump the specified namespace. This is to support * clearing the VM list when in inline-VM-local-scope mode * @param namespace * @return True if the Namespace was dumped. */ public boolean dumpVMNamespace( String namespace ); /** * String property accessor method to hide the configuration implementation * @param key property key * @return value of key or null */ public String getString(String key); /** * Int property accessor method to hide the configuration implementation. * * @param key property key * @return int value */ public int getInt( String key ); /** * Int property accessor method to hide the configuration implementation. * * @param key property key * @param defaultValue default value * @return int value */ public int getInt( String key, int defaultValue ); /** * Boolean property accessor method to hide the configuration implementation. * * @param key property key * @param def default default value if property not found * @return boolean value of key or default value */ public boolean getBoolean( String key, boolean def ); /** * Return the velocity runtime configuration object. * * @return ExtendedProperties configuration object which houses * the velocity runtime properties. */ public ExtendedProperties getConfiguration(); /** * Return the specified application attribute. * * @param key The name of the attribute to retrieve. * @return The value of the attribute. */ public Object getApplicationAttribute( Object key ); /** * Set the specified application attribute. * * @param key The name of the attribute to set. * @param value The attribute value to set. * @return the displaced attribute value */ public Object setApplicationAttribute( Object key, Object value ); /** * Returns the configured class introspection/reflection * implementation. * @return The current Uberspect object. */ public Uberspect getUberspect(); /** * Returns a convenient Log instance that wraps the current LogChute. * @return A log object. */ public Log getLog(); /** * Returns the event handlers for the application. * @return The event handlers for the application. */ public EventCartridge getApplicationEventCartridge(); /** * Returns the configured method introspection/reflection * implementation. * @return The configured method introspection/reflection * implementation. */ public Introspector getIntrospector(); /** * Returns true if the RuntimeInstance has been successfully initialized. * @return True if the RuntimeInstance has been successfully initialized. */ public boolean isInitialized(); /** * Create a new parser instance. * @return A new parser instance. */ public Parser createNewParser(); /** * Retrieve a previously instantiated directive. * @param name name of the directive * @return the directive with that name, if any * @since 1.6 */ public Directive getDirective(String name); }




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