ratpack.handling.internal.DescribingHandlers.java Source code

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Here is the source code for ratpack.handling.internal.DescribingHandlers.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 ratpack.handling.internal;

import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import javassist.ClassPool;
import javassist.CtBehavior;
import javassist.CtClass;
import javassist.NotFoundException;
import javassist.bytecode.ClassFile;
import ratpack.handling.Handler;

import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;

public class DescribingHandlers {

    public static void describeTo(Handler handler, StringBuilder stringBuilder) {
        Class<? extends Handler> clazz = handler.getClass();
        if (clazz.isAnonymousClass()) {
            ClassPool pool = ClassPool.getDefault();

            CtClass ctClass;
            try {
                ctClass = pool.get(clazz.getName());
                CtBehavior[] behaviors = ctClass.getDeclaredBehaviors();
                Iterable<CtBehavior> withLineNumberIterable = Iterables.filter(Arrays.asList(behaviors),
                        input -> input.getMethodInfo().getLineNumber(0) > 0);

                LinkedList<CtBehavior> withLineNumber = Lists.newLinkedList(withLineNumberIterable);
                Collections.sort(withLineNumber, (o1, o2) -> Integer.valueOf(o1.getMethodInfo().getLineNumber(0))
                        .compareTo(o2.getMethodInfo().getLineNumber(0)));

                if (!withLineNumber.isEmpty()) {
                    CtBehavior method = withLineNumber.get(0);
                    int lineNumber = method.getMethodInfo().getLineNumber(0);

                    ClassFile classFile = ctClass.getClassFile();
                    String sourceFile = classFile.getSourceFile();

                    if (lineNumber != -1 && sourceFile != null) {
                        stringBuilder.append("anonymous class ").append(clazz.getName())
                                .append(" at approximately line ").append(lineNumber).append(" of ")
                                .append(sourceFile);
                        return;
                    }
                }
            } catch (NotFoundException ignore) {
                // fall through
            }
        }

        stringBuilder.append(clazz.getName());
    }

}