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Google App Engine compliant variation of FreeMarker.
FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
*
* Licensed 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.
*/
package freemarker.core;
import freemarker.template.Template;
/**
* Objects that represent instructions or expressions
* in the compiled tree representation of the template
* all descend from this abstract base class.
*/
public abstract class TemplateObject {
private Template template;
int beginColumn, beginLine, endColumn, endLine;
/** This is needed for an ?eval hack; the expression AST nodes will be the descendants of the template, however,
* we can't give their position in the template, only in the dynamic string that's evaluated. That's signaled
* by a negative line numbers, starting from this constant as line 1. */
static final int RUNTIME_EVAL_LINE_DISPLACEMENT = -1000000000;
final void setLocation(Template template, Token begin, Token end)
throws
ParseException
{
setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine);
}
final void setLocation(Template template, Token begin, TemplateObject end)
throws
ParseException
{
setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine);
}
final void setLocation(Template template, TemplateObject begin, Token end)
throws
ParseException
{
setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine);
}
final void setLocation(Template template, TemplateObject begin, TemplateObject end)
throws
ParseException
{
setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine);
}
void setLocation(Template template, int beginColumn, int beginLine, int endColumn, int endLine)
throws
ParseException
{
this.template = template;
this.beginColumn = beginColumn;
this.beginLine = beginLine;
this.endColumn = endColumn;
this.endLine = endLine;
}
public final int getBeginColumn() {
return beginColumn;
}
public final int getBeginLine() {
return beginLine;
}
public final int getEndColumn() {
return endColumn;
}
public final int getEndLine() {
return endLine;
}
/**
* Returns a string that indicates
* where in the template source, this object is.
*/
public String getStartLocation() {
return MessageUtil.formatLocationForEvaluationError(template, beginLine, beginColumn);
}
/**
* As of 2.3.20. the same as {@link #getStartLocation}. Meant to be used where there's a risk of XSS
* when viewing error messages.
*/
public String getStartLocationQuoted() {
return getStartLocation();
}
public String getEndLocation() {
return MessageUtil.formatLocationForEvaluationError(template, endLine, endColumn);
}
/**
* As of 2.3.20. the same as {@link #getEndLocation}. Meant to be used where there's a risk of XSS
* when viewing error messages.
*/
public String getEndLocationQuoted() {
return getEndLocation();
}
public final String getSource() {
String s;
if (template != null) {
s = template.getSource(beginColumn, beginLine, endColumn, endLine);
} else {
s = null;
}
// Can't just return null for backward-compatibility...
return s != null ? s : getCanonicalForm();
}
public String toString() {
String s;
try {
s = getSource();
} catch (Exception e) { // REVISIT: A bit of a hack? (JR)
s = null;
}
return s != null ? s : getCanonicalForm();
}
/**
* @return whether the point in the template file specified by the
* column and line numbers is contained within this template object.
*/
public boolean contains(int column, int line) {
if (line < beginLine || line > endLine) {
return false;
}
if (line == beginLine) {
if (column < beginColumn) {
return false;
}
}
if (line == endLine) {
if (column > endColumn) {
return false;
}
}
return true;
}
public Template getTemplate()
{
return template;
}
TemplateObject copyLocationFrom(TemplateObject from)
{
template = from.template;
beginColumn = from.beginColumn;
beginLine = from.beginLine;
endColumn = from.endColumn;
endLine = from.endLine;
return this;
}
/**
* FTL generated from the AST of the node, which must be parseable to an AST that does the same as the original
* source, assuming we turn off automatic white-space removal when parsing the canonical form.
*
* @see TemplateElement#getDescription()
* @see #getNodeTypeSymbol()
*/
abstract public String getCanonicalForm();
/**
* A very sort single-line string that describes what kind of AST node this is, without describing any
* embedded expression or child element. Examples: {@code "#if"}, {@code "+"}, "${...}. These values should
* be suitable as tree node labels in a tree view. Yet, they should be consistent and complete enough so that an AST
* that is equivalent with the original could be reconstructed from the tree view. Thus, for literal values that are
* leaf nodes the symbols should be the canonical form of value.
*
* Note that {@link TemplateElement#getDescription()} has similar role, only it doesn't go under the element level
* (i.e. down to the expression level), instead it always prints the embedded expressions itself.
*
* @see #getCanonicalForm()
* @see TemplateElement#getDescription()
*/
abstract String getNodeTypeSymbol();
/**
* Returns highest valid parameter index + 1. So one should scan indexes with {@link #getParameterValue(int)}
* starting from 0 up until but excluding this. For example, for the binary "+" operator this will give 2, so the
* legal indexes are 0 and 1. Note that if a parameter is optional in a template-object-type and happens to be
* omitted in an instance, this will still return the same value and the value of that parameter will be
* {@code null}.
*/
abstract int getParameterCount();
/**
* Returns the value of the parameter identified by the index. For example, the binary "+" operator will have an
* LHO {@link Expression} at index 0, and and RHO {@link Expression} at index 1. Or, the binary "." operator will
* have an LHO {@link Expression} at index 0, and an RHO {@link String}(!) at index 1. Or, the {@code #include}
* directive will have a path {@link Expression} at index 0, a "parse" {@link Expression} at index 1, etc.
*
* The index value doesn't correspond to the source-code location in general. It's an arbitrary identifier
* that corresponds to the role of the parameter instead. This also means that when a parameter is omitted, the
* index of the other parameters won't shift.
*
* @return {@code null} or any kind of {@link Object}, very often an {@link Expression}. However, if there's
* a {@link TemplateObject} stored inside the returned value, it must itself be be a {@link TemplateObject}
* too, otherwise the AST couldn't be (easily) fully traversed. That is, non-{@link TemplateObject} values
* can only be used for leafs.
*
* @throws IndexOutOfBoundsException if {@code idx} is less than 0 or not less than {@link #getParameterCount()}.
*/
abstract Object getParameterValue(int idx);
/**
* Returns the role of the parameter at the given index, like {@link ParameterRole#LEFT_HAND_OPERAND}.
*
* As of this writing (2013-06-17), for directive parameters it will always give {@link ParameterRole#UNKNOWN},
* because there was no need to be more specific so far. This should be improved as need.
*
* @throws IndexOutOfBoundsException if {@code idx} is less than 0 or not less than {@link #getParameterCount()}.
*/
abstract ParameterRole getParameterRole(int idx);
}