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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.
/*
* 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.
*/
package freemarker.template.utility;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.HashSet;
import java.util.Properties;
import java.util.Set;
import freemarker.core.Environment;
import freemarker.core.Macro;
import freemarker.core.TemplateMarkupOutputModel;
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.TemplateCollectionModelEx;
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.TemplateNodeModelEx;
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(StringBuilder sb, Set typeNamesAppended, Class cl) {
int initalLength = sb.length();
if (TemplateNodeModelEx.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "extended node");
} else 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,
TemplateCollectionModelEx.class.isAssignableFrom(cl) ? "extended_collection" : "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");
}
if (TemplateMarkupOutputModel.class.isAssignableFrom(cl)) {
appendTypeName(sb, typeNamesAppended, "markup_output");
}
if (sb.length() == initalLength) {
appendTypeName(sb, typeNamesAppended, "misc_template_model");
}
}
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(StringBuilder 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();
StringBuilder sb = new StringBuilder();
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;
}
/**
* Very similar to {@link Class#getResourceAsStream(String)}, but throws {@link IOException} instead of returning
* {@code null} if {@code optional} is {@code false}, and attempts to work around "IllegalStateException: zip file
* closed" and similar {@code sun.net.www.protocol.jar.JarURLConnection}-related glitches. These are caused by bugs
* outside of FreeMarker. Note that in cases where the JAR resource becomes broken concurrently, similar errors can
* still occur later when the {@link InputStream} is read ({@link #loadProperties(Class, String)} works that
* around as well).
*
* @return If {@code optional} is {@code false}, it's never {@code null}, otherwise {@code null} indicates that the
* resource doesn't exist.
* @throws IOException
* If the resource wasn't found, or other {@link IOException} occurs.
*
* @since 2.3.27
*/
public static InputStream getReasourceAsStream(Class baseClass, String resource, boolean optional)
throws IOException {
InputStream ins;
try {
// This is how we did this earlier. May uses some JarURLConnection caches, which leads to the problems.
ins = baseClass.getResourceAsStream(resource);
} catch (Exception e) {
// Workaround for "IllegalStateException: zip file closed", and other related exceptions. This happens due
// to bugs outside of FreeMarker, but we try to work it around anyway.
URL url = baseClass.getResource(resource);
ins = url != null ? url.openStream() : null;
}
if (!optional) {
checkInputStreamNotNull(ins, baseClass, resource);
}
return ins;
}
/**
* Same as {@link #getReasourceAsStream(Class, String, boolean)}, but uses a {@link ClassLoader} directly
* instead of a {@link Class}.
*
* @since 2.3.27
*/
public static InputStream getReasourceAsStream(ClassLoader classLoader, String resource, boolean optional)
throws IOException {
// See source commends in the other overload of this method.
InputStream ins;
try {
ins = classLoader.getResourceAsStream(resource);
} catch (Exception e) {
URL url = classLoader.getResource(resource);
ins = url != null ? url.openStream() : null;
}
if (ins == null && !optional) {
throw new IOException("Class-loader resource not found (shown quoted): "
+ StringUtil.jQuote(resource) + ". The base ClassLoader was: " + classLoader);
}
return ins;
}
/**
* Loads a class loader resource into a {@link Properties}; tries to work around "zip file closed" and related
* {@code sun.net.www.protocol.jar.JarURLConnection} glitches.
*
* @since 2.3.27
*/
public static Properties loadProperties(Class baseClass, String resource) throws IOException {
Properties props = new Properties();
InputStream ins = null;
try {
try {
// This is how we did this earlier. May uses some JarURLConnection caches, which leads to the problems.
ins = baseClass.getResourceAsStream(resource);
} catch (Exception e) {
throw new MaybeZipFileClosedException();
}
checkInputStreamNotNull(ins, baseClass, resource);
try {
props.load(ins);
} catch (Exception e) {
throw new MaybeZipFileClosedException();
} finally {
try {
ins.close();
} catch (Exception e) {
// Do nothing to suppress "ZipFile closed" and related exceptions.
}
ins = null;
}
} catch (MaybeZipFileClosedException e) {
// Workaround for "zip file closed" exception, and other related exceptions. This happens due to bugs
// outside of FreeMarker, but we try to work it around anyway.
URL url = baseClass.getResource(resource);
ins = url != null ? url.openStream() : null;
checkInputStreamNotNull(ins, baseClass, resource);
props.load(ins);
} finally {
if (ins != null) {
try {
ins.close();
} catch (Exception e) {
// Do nothing to suppress "ZipFile closed" and related exceptions.
}
}
}
return props;
}
private static void checkInputStreamNotNull(InputStream ins, Class baseClass, String resource)
throws IOException {
if (ins == null) {
throw new IOException("Class-loader resource not found (shown quoted): "
+ StringUtil.jQuote(resource) + ". The base class was " + baseClass.getName() + ".");
}
}
/** Used internally to work around some JarURLConnection glitches */
private static class MaybeZipFileClosedException extends Exception {
//
}
}