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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.template.utility;
import java.util.HashSet;
import java.util.Set;
import freemarker.core.Environment;
import freemarker.core.Macro;
import freemarker.ext.beans.BeanModel;
import freemarker.ext.beans.BooleanModel;
import freemarker.ext.beans.CollectionModel;
import freemarker.ext.beans.DateModel;
import freemarker.ext.beans.EnumerationModel;
import freemarker.ext.beans.IteratorModel;
import freemarker.ext.beans.MapModel;
import freemarker.ext.beans.NumberModel;
import freemarker.ext.beans.OverloadedMethodsModel;
import freemarker.ext.beans.SimpleMethodModel;
import freemarker.ext.beans.StringModel;
import freemarker.ext.util.WrapperTemplateModel;
import freemarker.template.AdapterTemplateModel;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateDateModel;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateHashModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateMethodModel;
import freemarker.template.TemplateMethodModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelIterator;
import freemarker.template.TemplateNodeModel;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateSequenceModel;
import freemarker.template.TemplateTransformModel;
/**
*/
public class ClassUtil
{
private ClassUtil()
{
}
/**
* Similar to {@link Class#forName(java.lang.String)}, but attempts to load
* through the thread context class loader. Only if thread context class
* loader is inaccessible, or it can't find the class will it attempt to
* fall back to the class loader that loads the FreeMarker classes.
*/
public static Class forName(String className)
throws
ClassNotFoundException
{
try
{
ClassLoader ctcl = Thread.currentThread().getContextClassLoader();
if (ctcl != null) { // not null: we don't want to fall back to the bootstrap class loader
return Class.forName(className, true, ctcl);
}
}
catch(ClassNotFoundException e)
{
;// Intentionally ignored
}
catch(SecurityException e)
{
;// Intentionally ignored
}
// Fall back to the defining class loader of the FreeMarker classes
return Class.forName(className);
}
/**
* Same as {@link #getShortClassName(Class, boolean) getShortClassName(pClass, false)}.
*
* @since 2.3.20
*/
public static String getShortClassName(Class pClass) {
return getShortClassName(pClass, false);
}
/**
* Returns a class name without "java.lang." and "java.util." prefix, also shows array types in a format like
* {@code int[]}; useful for printing class names in error messages.
*
* @param pClass can be {@code null}, in which case the method returns {@code null}.
* @param shortenFreeMarkerClasses if {@code true}, it will also shorten FreeMarker class names. The exact rules
* aren't specified and might change over time, but right now, {@code freemarker.ext.beans.NumberModel} for
* example becomes to {@code f.e.b.NumberModel}.
*
* @since 2.3.20
*/
public static String getShortClassName(Class pClass, boolean shortenFreeMarkerClasses) {
if (pClass == null) {
return null;
} else if (pClass.isArray()) {
return getShortClassName(pClass.getComponentType()) + "[]";
} else {
String cn = pClass.getName();
if (cn.startsWith("java.lang.") || cn.startsWith("java.util.")) {
return cn.substring(10);
} else {
if (shortenFreeMarkerClasses) {
if (cn.startsWith("freemarker.template.")) {
return "f.t" + cn.substring(19);
} else if (cn.startsWith("freemarker.ext.beans.")) {
return "f.e.b" + cn.substring(20);
} else if (cn.startsWith("freemarker.core.")) {
return "f.c" + cn.substring(15);
} else if (cn.startsWith("freemarker.ext.")) {
return "f.e" + cn.substring(14);
} else if (cn.startsWith("freemarker.")) {
return "f" + cn.substring(10);
}
// Falls through
}
return cn;
}
}
}
/**
* Same as {@link #getShortClassNameOfObject(Object, boolean) getShortClassNameOfObject(pClass, false)}.
*
* @since 2.3.20
*/
public static String getShortClassNameOfObject(Object obj) {
return getShortClassNameOfObject(obj, false);
}
/**
* {@link #getShortClassName(Class, boolean)} called with {@code object.getClass()}, but returns the fictional
* class name {@code Null} for a {@code null} value.
*
* @since 2.3.20
*/
public static String getShortClassNameOfObject(Object obj, boolean shortenFreeMarkerClasses) {
if (obj == null) {
return "Null";
} else {
return ClassUtil.getShortClassName(obj.getClass(), shortenFreeMarkerClasses);
}
}
/**
* Returns the {@link TemplateModel} interface that is the most characteristic of the object, or {@code null}.
*/
private static Class getPrimaryTemplateModelInterface(TemplateModel tm) {
if (tm instanceof BeanModel) {
if (tm instanceof CollectionModel) {
return TemplateSequenceModel.class;
} else if (tm instanceof IteratorModel || tm instanceof EnumerationModel) {
return TemplateCollectionModel.class;
} else if (tm instanceof MapModel) {
return TemplateHashModelEx.class;
} else if (tm instanceof NumberModel) {
return TemplateNumberModel.class;
} else if (tm instanceof BooleanModel) {
return TemplateBooleanModel.class;
} else if (tm instanceof DateModel) {
return TemplateDateModel.class;
} else if (tm instanceof StringModel) {
Object wrapped = ((BeanModel) tm).getWrappedObject();
return wrapped instanceof String
? TemplateScalarModel.class
: (tm instanceof TemplateHashModelEx ? TemplateHashModelEx.class : null);
} else {
return null;
}
} else if (tm instanceof SimpleMethodModel || tm instanceof OverloadedMethodsModel) {
return TemplateMethodModelEx.class;
} else {
return null;
}
}
private static void appendTemplateModelTypeName(StringBuffer sb, Set typeNamesAppended, Class cl) {
if (TemplateNodeModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "node");
}
if (TemplateDirectiveModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "directive");
} else if (TemplateTransformModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "transform");
}
if (TemplateSequenceModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "sequence");
} else if (TemplateCollectionModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "collection");
} else if (TemplateModelIterator.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "iterator");
}
if (TemplateMethodModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "method");
}
if (Environment.Namespace.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "namespace");
} else if (TemplateHashModelEx.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "extended_hash");
} else if (TemplateHashModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "hash");
}
if (TemplateNumberModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "number");
}
if (TemplateDateModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "date_or_time_or_datetime");
}
if (TemplateBooleanModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "boolean");
}
if (TemplateScalarModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "string");
}
}
private static Class getUnwrappedClass(TemplateModel tm) {
Object unwrapped;
try {
if (tm instanceof WrapperTemplateModel) {
unwrapped = ((WrapperTemplateModel) tm).getWrappedObject();
} else if (tm instanceof AdapterTemplateModel) {
unwrapped = ((AdapterTemplateModel) tm).getAdaptedObject(Object.class);
} else {
unwrapped = null;
}
} catch (Throwable e) {
unwrapped = null;
}
return unwrapped != null ? unwrapped.getClass() : null;
}
private static void appendTypeName(StringBuffer sb, Set typeNamesAppended, String name) {
if (!typeNamesAppended.contains(name)) {
if (sb.length() != 0) sb.append("+");
sb.append(name);
typeNamesAppended.add(name);
}
}
/**
* Returns the type description of a value with FTL terms (not plain class name), as it should be used in
* type-related error messages and for debugging purposes. The exact format is not specified and might change over
* time, but currently it's something like {@code "string (wrapper: f.t.SimpleScalar)"} or
* {@code "sequence+hash+string (ArrayList wrapped into f.e.b.CollectionModel)"}.
*
* @since 2.3.20
*/
public static String getFTLTypeDescription(TemplateModel tm) {
if (tm == null) {
return "Null";
} else {
Set typeNamesAppended = new HashSet();
StringBuffer sb = new StringBuffer();
Class primaryInterface = getPrimaryTemplateModelInterface(tm);
if (primaryInterface != null) {
appendTemplateModelTypeName(sb, typeNamesAppended, primaryInterface);
}
if (tm instanceof Macro) {
appendTypeName(sb, typeNamesAppended, ((Macro) tm).isFunction() ? "function" : "macro");
}
appendTemplateModelTypeName(sb, typeNamesAppended, tm.getClass());
String javaClassName;
Class unwrappedClass = getUnwrappedClass(tm);
if (unwrappedClass != null) {
javaClassName = getShortClassName(unwrappedClass, true);
} else {
javaClassName = null;
}
sb.append(" (");
String modelClassName = getShortClassName(tm.getClass(), true);
if (javaClassName == null) {
sb.append("wrapper: ");
sb.append(modelClassName);
} else {
sb.append(javaClassName);
sb.append(" wrapped into ");
sb.append(modelClassName);
}
sb.append(")");
return sb.toString();
}
}
/**
* Gets the wrapper class for a primitive class, like {@link Integer} for {@code int}, also returns {@link Void}
* for {@code void}.
*
* @param primitiveClass A {@link Class} like {@code int.type}, {@code boolean.type}, etc. If it's not a primitive
* class, or it's {@code null}, then the parameter value is returned as is. Note that performance-wise the
* method assumes that it's a primitive class.
*
* @since 2.3.21
*/
public static Class primitiveClassToBoxingClass(Class primitiveClass) {
// Tried to sort these with decreasing frequency in API-s:
if (primitiveClass == int.class) return Integer.class;
if (primitiveClass == boolean.class) return Boolean.class;
if (primitiveClass == long.class) return Long.class;
if (primitiveClass == double.class) return Double.class;
if (primitiveClass == char.class) return Character.class;
if (primitiveClass == float.class) return Float.class;
if (primitiveClass == byte.class) return Byte.class;
if (primitiveClass == short.class) return Short.class;
if (primitiveClass == void.class) return Void.class; // not really a primitive, but we normalize it
return primitiveClass;
}
/**
* The exact reverse of {@link #primitiveClassToBoxingClass}.
*
* @since 2.3.21
*/
public static Class boxingClassToPrimitiveClass(Class boxingClass) {
// Tried to sort these with decreasing frequency in API-s:
if (boxingClass == Integer.class) return int.class;
if (boxingClass == Boolean.class) return boolean.class;
if (boxingClass == Long.class) return long.class;
if (boxingClass == Double.class) return double.class;
if (boxingClass == Character.class) return char.class;
if (boxingClass == Float.class) return float.class;
if (boxingClass == Byte.class) return byte.class;
if (boxingClass == Short.class) return short.class;
if (boxingClass == Void.class) return void.class; // not really a primitive, but we normalize to it
return boxingClass;
}
/**
* Tells if a type is numerical; works both for primitive types and classes.
*
* @param type can't be {@code null}
*
* @since 2.3.21
*/
public static boolean isNumerical(Class type) {
return Number.class.isAssignableFrom(type)
|| type.isPrimitive() && type != Boolean.TYPE && type != Character.TYPE && type != Void.TYPE;
}
}
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