freemarker.core.Expression Maven / Gradle / Ivy
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FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* Copyright (c) 2003 The Visigoth Software Society. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Visigoth Software Society (http://www.visigoths.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
* project contributors may be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
* nor may "FreeMarker" or "Visigoth" appear in their names
* without prior written permission of the Visigoth Software Society.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Visigoth Software Society. For more
* information on the Visigoth Software Society, please see
* http://www.visigoths.org/
*/
package freemarker.core;
import freemarker.template.*;
import freemarker.ext.beans.BeanModel;
/**
* An abstract class for nodes in the parse tree
* that represent a FreeMarker expression.
*/
abstract public class Expression extends TemplateObject {
abstract TemplateModel _getAsTemplateModel(Environment env) throws TemplateException;
abstract boolean isLiteral();
// Used to store a constant return value for this expression. Only if it
// is possible, of course.
TemplateModel constantValue;
// Hook in here to set the constant value if possible.
void setLocation(Template template, int beginColumn, int beginLine, int endColumn, int endLine)
throws
ParseException
{
super.setLocation(template, beginColumn, beginLine, endColumn, endLine);
if (isLiteral()) {
try {
constantValue = _getAsTemplateModel(null);
} catch (Exception e) {
// deliberately ignore.
}
}
}
public final TemplateModel getAsTemplateModel(Environment env) throws TemplateException {
return constantValue != null ? constantValue : _getAsTemplateModel(env);
}
String getStringValue(Environment env) throws TemplateException {
return getStringValue(getAsTemplateModel(env), this, env);
}
static String getStringValue(TemplateModel referentModel, Expression exp, Environment env)
throws
TemplateException
{
if (referentModel instanceof TemplateNumberModel) {
return env.formatNumber(EvaluationUtil.getNumber((TemplateNumberModel) referentModel, exp, env));
}
if (referentModel instanceof TemplateDateModel) {
TemplateDateModel dm = (TemplateDateModel) referentModel;
return env.formatDate(EvaluationUtil.getDate(dm, exp, env), dm.getDateType());
}
if (referentModel instanceof TemplateScalarModel) {
return EvaluationUtil.getString((TemplateScalarModel) referentModel, exp, env);
}
if(env.isClassicCompatible()) {
if (referentModel instanceof TemplateBooleanModel) {
return ((TemplateBooleanModel)referentModel).getAsBoolean() ? "true" : "";
}
if (referentModel == null) {
return "";
}
}
assertNonNull(referentModel, exp, env);
String msg = "Error " + exp.getStartLocation()
+"\nExpecting a string, "
+ (env.isClassicCompatible() ? "boolean, " : "" )
+ "date or number here, Expression " + exp
+ " is instead a "
+ referentModel.getClass().getName();
throw new NonStringException(msg, env);
}
Expression deepClone(String name, Expression subst) {
Expression clone = _deepClone(name, subst);
clone.copyLocationFrom(this);
return clone;
}
abstract Expression _deepClone(String name, Expression subst);
boolean isTrue(Environment env) throws TemplateException {
TemplateModel referent = getAsTemplateModel(env);
if (referent instanceof TemplateBooleanModel) {
return ((TemplateBooleanModel) referent).getAsBoolean();
}
if (env.isClassicCompatible()) {
return referent != null && !isEmpty(referent);
}
assertNonNull(referent, this, env);
String msg = "Error " + getStartLocation()
+ "\nExpecting a boolean (true/false) expression here"
+ "\nExpression " + this + " does not evaluate to true/false "
+ "\nit is an instance of " + referent.getClass().getName();
throw new NonBooleanException(msg, env);
}
static boolean isEmpty(TemplateModel model) throws TemplateModelException
{
if (model instanceof BeanModel) {
return ((BeanModel) model).isEmpty();
} else if (model instanceof TemplateSequenceModel) {
return ((TemplateSequenceModel) model).size() == 0;
} else if (model instanceof TemplateScalarModel) {
String s = ((TemplateScalarModel) model).getAsString();
return (s == null || s.length() == 0);
} else if (model instanceof TemplateCollectionModel) {
return !((TemplateCollectionModel) model).iterator().hasNext();
} else if (model instanceof TemplateHashModel) {
return ((TemplateHashModel) model).isEmpty();
} else if (model instanceof TemplateNumberModel
|| model instanceof TemplateDateModel
|| model instanceof TemplateBooleanModel) {
return false;
} else {
return true;
}
}
}