freemarker.template.TemplateExceptionHandler Maven / Gradle / Ivy
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/*
* 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;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import freemarker.core.Configurable;
import freemarker.core.Environment;
import freemarker.core.StopException;
import freemarker.template.utility.StringUtil;
/**
* Used for the {@code template_exception_handler} configuration setting;
* see {@link Configurable#setTemplateExceptionHandler(TemplateExceptionHandler)} for more.
*/
public interface TemplateExceptionHandler {
/**
* Method called after a {@link TemplateException} was raised inside a template. The error is logged before this is
* called, so there's no need to log it here. The exception should be re-thrown unless you want to
* suppress the exception.
*
* Note that you can check with {@link Environment#isInAttemptBlock()} if you are inside a {@code #attempt}
* block, which then will handle handle this exception and roll back the output generated inside it.
*
*
Note that {@link StopException}-s (raised by {@code #stop}) won't be captured.
*
* @param te The exception that occurred; don't forget to re-throw it unless you want to suppress it
* @param env The runtime environment of the template
* @param out This is where the output of the template is written
*/
void handleTemplateException(TemplateException te, Environment env, Writer out) throws TemplateException;
/**
* {@link TemplateExceptionHandler} that simply skips the failing instructions, letting the template continue
* executing. It does nothing to handle the event. Note that the exception is still logged, as with all
* other {@link TemplateExceptionHandler}-s.
*/
TemplateExceptionHandler IGNORE_HANDLER = new TemplateExceptionHandler() {
public void handleTemplateException(TemplateException te, Environment env, Writer out) {
// Do nothing
}
};
/**
* {@link TemplateExceptionHandler} that simply re-throws the exception; this should be used in most production
* systems.
*/
TemplateExceptionHandler RETHROW_HANDLER =new TemplateExceptionHandler() {
public void handleTemplateException(TemplateException te, Environment env, Writer out)
throws TemplateException {
throw te;
}
};
/**
* {@link TemplateExceptionHandler} useful when you developing non-HTML templates. This handler
* outputs the stack trace information to the client and then re-throws the exception.
*/
TemplateExceptionHandler DEBUG_HANDLER =new TemplateExceptionHandler() {
public void handleTemplateException(TemplateException te, Environment env, Writer out)
throws TemplateException {
if (!env.isInAttemptBlock()) {
PrintWriter pw = (out instanceof PrintWriter) ? (PrintWriter) out : new PrintWriter(out);
te.printStackTrace(pw);
pw.flush();
}
throw te;
}
};
/**
* {@link TemplateExceptionHandler} useful when you developing HTML templates. This handler
* outputs the stack trace information to the client, formatting it so that it will be usually well readable
* in the browser, and then re-throws the exception.
*/
TemplateExceptionHandler HTML_DEBUG_HANDLER = new TemplateExceptionHandler() {
public void handleTemplateException(TemplateException te, Environment env, Writer out)
throws TemplateException {
if (!env.isInAttemptBlock()) {
boolean externalPw = out instanceof PrintWriter;
PrintWriter pw = externalPw ? (PrintWriter) out : new PrintWriter(out);
try {
pw.print(""
+ ""
+ ""
+ ""
+ ""
+ ""
+ ""
+ "
");
StringWriter stackTraceSW = new StringWriter();
PrintWriter stackPW = new PrintWriter(stackTraceSW);
te.printStackTrace(stackPW, false, true, true);
stackPW.close();
pw.println();
pw.println(StringUtil.XMLEncNQG(stackTraceSW.toString()));
pw.println("