/*
* FreeMarker: a tool that allows Java programs to generate HTML
* output using templates.
* Copyright (C) 1998-2004 Benjamin Geer
* Email: beroul@users.sourceforge.net
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
package freemarker.template.instruction;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.io.Writer;
import freemarker.template.TemplateException;
import freemarker.template.TemplateProcessor;
import freemarker.template.TemplateRuntimeHandler;
import freemarker.template.TemplateWriteableHashModel;
import freemarker.template.cache.Cache;
import freemarker.template.cache.Cacheable;
import freemarker.template.expression.Expression;
import freemarker.template.expression.ExpressionUtils;
/**
* An instruction that gets another template from a
* {@link freemarker.template.cache.Cache}, and processes it within the current
* template.
*
* @version $Id: IncludeInstruction.java 1123 2005-10-04 10:48:25Z run2000 $
*/
public final class IncludeInstruction extends EmptyInstruction implements Serializable {
/**
* @serial the template to which this include instruction belongs
*/
private final TemplateProcessor template;
/**
* @serial an expression that determines name of the template to be included
*/
private final Expression name;
/**
* @serial an expression that determines the type of template to be included
*/
private final Expression type;
/** Serialization UUID for this class. */
private static final long serialVersionUID = 8423827110332040952L;
/**
* Constructor that takes the originating template and the name of the
* template to be included.
*
* @param template
* the template that this <code>Include</code> is a part of.
* Provided so that the instruction can locate a
* {@link freemarker.template.cache.Cache} instance.
* @param name
* the name, in the <code>TemplateCache</code>, of the template
* to be included.
* @throws NullPointerException
* template or template name are null
* @throws IllegalArgumentException
* template name is not a string or number
*/
public IncludeInstruction(TemplateProcessor template, Expression name) {
this(template, name, null);
}
/**
* Constructor that takes the originating template, the name of the template
* to be included and the type of template.
*
* @param template
* the template that this <code>Include</code> is a part of.
* @param name
* the name, in the <code>TemplateCache</code>, of the template
* to be included.
* @param type
* the type of the template, as known by the
* <code>TemplateRegistry</code>, or <code>null</code>
* @throws NullPointerException
* template or template name are null
* @throws IllegalArgumentException
* template name is not a string or number, or template type is
* not null, a string, or a number
*/
public IncludeInstruction(TemplateProcessor template, Expression name, Expression type) {
if (template == null) {
throw new NullPointerException("Template for Include instruction cannot be null");
}
if ((name.getType() & (ExpressionUtils.EXPRESSION_TYPE_STRING | ExpressionUtils.EXPRESSION_TYPE_NUMBER)) == 0) {
throw new IllegalArgumentException("Template name for Include instruction must be scalar or numeric");
}
if ((type != null) && ((type.getType() & (ExpressionUtils.EXPRESSION_TYPE_STRING | ExpressionUtils.EXPRESSION_TYPE_NUMBER)) == 0)) {
throw new IllegalArgumentException("Template type for Include instruction must be scalar or numeric");
}
this.template = template;
this.name = name;
this.type = type;
}
/**
* Evaluate the template being included by this instruction.
*
* @param modelRoot
* the root node of the data model.
* @param out
* a <code>Writer</code> to send the output to.
* @param eventHandler
* a <code>TemplateEventAdapter</code> for handling any events
* that occur during processing.
*/
public short process(TemplateWriteableHashModel modelRoot, Writer out, TemplateRuntimeHandler eventHandler) throws IOException {
Cache cache = null;
if (template instanceof Cacheable) {
cache = ((Cacheable) template).getCache();
}
if (cache == null) {
eventHandler.fireExceptionThrown(this, new TemplateException("The current template wasn't given a reference to a Cache"), out,
"freemarker.template.instruction.IncludeInstruction.process", TemplateRuntimeHandler.SEVERITY_WARNING);
return TemplateProcessor.OK;
}
String itemName;
try {
itemName = ExpressionUtils.getAsString(name.getAsTemplateModel(modelRoot));
} catch (TemplateException e) {
eventHandler.fireExceptionThrown(this, new TemplateException("Error in template name expression", e), out,
"freemarker.template.instruction.IncludeInstruction.process", TemplateRuntimeHandler.SEVERITY_WARNING);
return TemplateProcessor.OK;
}
if (itemName == null) {
eventHandler.fireExceptionThrown(this, new TemplateException("Error in template name expression: " + "expression evaluates to null"), out,
"freemarker.template.instruction.IncludeInstruction.process", TemplateRuntimeHandler.SEVERITY_WARNING);
return TemplateProcessor.OK;
}
String itemType = null;
try {
if (type != null) {
itemType = ExpressionUtils.getAsString(type.getAsTemplateModel(modelRoot));
}
} catch (TemplateException e) {
eventHandler.fireExceptionThrown(this, new TemplateException("Error in template type expression", e), out,
"freemarker.template.instruction.IncludeInstruction.process", TemplateRuntimeHandler.SEVERITY_WARNING);
return TemplateProcessor.OK;
}
TemplateProcessor includedTemplate;
if (itemType == null) {
includedTemplate = (TemplateProcessor) cache.getItem(itemName);
} else {
includedTemplate = (TemplateProcessor) cache.getItem(itemName, itemType);
}
if (includedTemplate == null) {
eventHandler.fireExceptionThrown(this, new TemplateException("Template \"" + itemName + "\" not found in cache"), out,
"freemarker.template.instruction.IncludeInstruction.process", TemplateRuntimeHandler.SEVERITY_WARNING);
return TemplateProcessor.OK;
}
includedTemplate.process(modelRoot, out, eventHandler);
return TemplateProcessor.OK;
}
/**
* Returns a string representation of the object.
*
* @return a <code>String</code> representing this instruction subtree
*/
public String toString() {
StringBuffer buffer = new StringBuffer();
buffer.append("include ");
buffer.append(name);
if (type != null) {
buffer.append(" of type ");
buffer.append(type);
}
return buffer.toString();
}
/**
* For serialization, read this object normally, then check whether the
* parent template or the name are null.
*
* @param stream
* the input stream to read serialized objects from
*/
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
stream.defaultReadObject();
if ((template == null) || (name == null)) {
throw new InvalidObjectException("Cannot create an IncludeInstruction with a null template or name");
}
}
}