org.apache.velocity.runtime.directive.Directive Maven / Gradle / Ivy
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package org.apache.velocity.runtime.directive;
/*
* 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.InternalContextAdapter;
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.runtime.RuntimeServices;
import org.apache.velocity.runtime.parser.ParseException;
import org.apache.velocity.runtime.parser.Token;
import org.apache.velocity.runtime.parser.node.Node;
import org.slf4j.Logger;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
/**
* Base class for all directives used in Velocity.
*
* @author Jason van Zyl
* @author Nathan Bubna
* @version $Id$
*/
public abstract class Directive implements DirectiveConstants, Cloneable
{
private int line = 0;
private int column = 0;
private boolean provideScope = false;
private Template template;
protected Logger log = null;
/**
*
*/
protected RuntimeServices rsvc = null;
/**
* Return the name of this directive.
* @return The name of this directive.
*/
public abstract String getName();
/**
* Get the directive type BLOCK/LINE.
* @return The directive type BLOCK/LINE.
*/
public abstract int getType();
/**
* Allows the template location to be set.
* @param line
* @param column
*/
public void setLocation( int line, int column )
{
this.line = line;
this.column = column;
}
/**
* Allows the template location to be set.
* @param line
* @param column
* @param template
*/
public void setLocation(int line, int column, Template template)
{
setLocation(line, column);
this.template = template;
}
/**
* returns the template in which this directive appears
* @return template
*/
public Template getTemplate()
{
return template;
}
/**
* for log msg purposes
* @return The current line for log msg purposes.
*/
public int getLine()
{
return line;
}
/**
* for log msg purposes
* @return The current column for log msg purposes.
*/
public int getColumn()
{
return column;
}
/**
* @return The template file name this directive was defined in, or null if not
* defined in a file.
*/
public String getTemplateName()
{
return template.getName();
}
/**
* @return the name to be used when a scope control is provided for this
* directive.
*/
public String getScopeName()
{
return getName();
}
/**
* @return true if there will be a scope control injected into the context
* when rendering this directive.
*/
public boolean isScopeProvided()
{
return provideScope;
}
/**
* How this directive is to be initialized.
* @param rs
* @param context
* @param node
* @throws TemplateInitException
*/
public void init( RuntimeServices rs, InternalContextAdapter context,
Node node)
throws TemplateInitException
{
rsvc = rs;
log = rsvc.getLog("directive." + getName());
provideScope = rsvc.isScopeControlEnabled(getScopeName());
}
/**
* The Parser calls this method during template parsing to check the arguments
* types. Be aware that this method is called pre init, so not all data
* is available in this method. The default implementation does not peform any
* checking. We do this so that Custom directives do not trigger any parse
* errors in IDEs.
* @param argtypes type, Array of argument types of each argument to the directive
* for example ParserTreeConstants.JJTWORD
* @param t token of directive
* @param templateName the name of the template this directive is referenced in.
* @throws ParseException
*/
public void checkArgs(ArrayList argtypes, Token t, String templateName)
throws ParseException
{
}
/**
* How this directive is to be rendered
* @param context
* @param writer
* @param node
* @return True if the directive rendered successfully.
* @throws IOException
* @throws ResourceNotFoundException
* @throws ParseErrorException
* @throws MethodInvocationException
*/
public abstract boolean render( InternalContextAdapter context,
Writer writer, Node node )
throws IOException, ResourceNotFoundException, ParseErrorException,
MethodInvocationException;
/**
* This creates and places the scope control for this directive
* into the context (if scope provision is turned on).
* @param context
*/
protected void preRender(InternalContextAdapter context)
{
if (isScopeProvided())
{
String name = getScopeName();
Object previous = context.get(name);
context.put(name, makeScope(previous));
}
}
/**
* @param prev
* @return scope
*/
protected Scope makeScope(Object prev)
{
return new Scope(this, prev);
}
/**
* This cleans up any scope control for this directive after rendering,
* assuming the scope control was turned on.
* @param context
*/
protected void postRender(InternalContextAdapter context)
{
if (isScopeProvided())
{
String name = getScopeName();
Object obj = context.get(name);
try
{
Scope scope = (Scope)obj;
if (scope.getParent() != null)
{
context.put(name, scope.getParent());
}
else if (scope.getReplaced() != null)
{
context.put(name, scope.getReplaced());
}
else
{
context.remove(name);
}
}
catch (ClassCastException cce)
{
// the user can override the scope with a #set,
// since that means they don't care about a replaced value
// and obviously aren't too keen on their scope control,
// and especially since #set is meant to be handled globally,
// we'll assume they know what they're doing and not worry
// about replacing anything superseded by this directive's scope
}
}
}
}