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 java.io.Writer; | |
import java.io.IOException; | |
import java.io.StringWriter; | |
import org.apache.commons.lang.text.StrBuilder; | |
import org.apache.velocity.context.InternalContextAdapter; | |
import org.apache.velocity.exception.TemplateInitException; | |
import org.apache.velocity.exception.VelocityException; | |
import org.apache.velocity.runtime.Renderable; | |
import org.apache.velocity.runtime.RuntimeServices; | |
import org.apache.velocity.runtime.log.Log; | |
import org.apache.velocity.runtime.parser.node.Node; | |
/** | |
* Directive that puts an unrendered AST block in the context | |
* under the specified key, postponing rendering until the | |
* reference is used and rendered. | |
* | |
* @author Andrew Tetlaw | |
* @author Nathan Bubna | |
* @author <a href="mailto:wyla@removethis.sci.fi">Jarkko Viinamaki</a> | |
* @since 1.7 | |
* @version $Id: Block.java 686842 2008-08-18 18:29:31Z nbubna $ | |
*/ | |
public abstract class Block extends Directive | |
{ | |
protected Node block; | |
protected Log log; | |
protected int maxDepth; | |
protected String key; | |
/** | |
* Return type of this directive. | |
*/ | |
public int getType() | |
{ | |
return BLOCK; | |
} | |
/** | |
* simple init - get the key | |
*/ | |
public void init(RuntimeServices rs, InternalContextAdapter context, Node node) | |
throws TemplateInitException | |
{ | |
super.init(rs, context, node); | |
log = rs.getLog(); | |
/** | |
* No checking is done. We just grab the last child node and assume | |
* that it's the block! | |
*/ | |
block = node.jjtGetChild(node.jjtGetNumChildren() - 1); | |
} | |
/** | |
* Creates a string identifying the source and location of the block | |
* definition, and the current template being rendered if that is | |
* different. | |
*/ | |
protected String id(InternalContextAdapter context) | |
{ | |
StrBuilder str = new StrBuilder(100) | |
.append("block $").append(key); | |
if (!context.getCurrentTemplateName().equals(getTemplateName())) | |
{ | |
str.append(" used in ").append(context.getCurrentTemplateName()); | |
} | |
return str.toString(); | |
} | |
/** | |
* actual class placed in the context, holds the context | |
* being used for the render, as well as the parent (which already holds | |
* everything else we need). | |
*/ | |
public static class Reference implements Renderable | |
{ | |
private InternalContextAdapter context; | |
private Block parent; | |
private int depth; | |
public Reference(InternalContextAdapter context, Block parent) | |
{ | |
this.context = context; | |
this.parent = parent; | |
} | |
/** | |
* Render the AST of this block into the writer using the context. | |
*/ | |
public boolean render(InternalContextAdapter context, Writer writer) | |
{ | |
try | |
{ | |
depth++; | |
if (depth > parent.maxDepth) | |
{ | |
/* this is only a debug message, as recursion can | |
* happen in quasi-innocent situations and is relatively | |
* harmless due to how we handle it here. | |
* this is more to help anyone nuts enough to intentionally | |
* use recursive block definitions and having problems | |
* pulling it off properly. | |
*/ | |
parent.log.debug("Max recursion depth reached for " + parent.id(context) | |
+ " at " + Log.formatFileString(parent)); | |
depth--; | |
return false; | |
} | |
else | |
{ | |
parent.block.render(context, writer); | |
depth--; | |
return true; | |
} | |
} | |
catch (IOException e) | |
{ | |
String msg = "Failed to render " + parent.id(context) + " to writer " | |
+ " at " + Log.formatFileString(parent); | |
parent.log.error(msg, e); | |
throw new RuntimeException(msg, e); | |
} | |
} | |
public String toString() | |
{ | |
Writer writer = new StringWriter(); | |
if (render(context, writer)) | |
{ | |
return writer.toString(); | |
} | |
return null; | |
} | |
} | |
} |