ApmMethodVisitor.java

/**
 *  Copyright 2005-2016 Red Hat, Inc.
 *
 *  Red Hat 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 io.fabric8.apmagent.strategy.trace;

import org.objectweb.asm.MethodVisitor;

import static org.objectweb.asm.Opcodes.*;

public class ApmMethodVisitor extends MethodVisitor {
    private final String fullMethodName;

    public ApmMethodVisitor(MethodVisitor mv, String className, String methodName) {
        super(ASM5, mv);
        this.fullMethodName = className + "@" + methodName;
    }

    @Override
    public void visitCode() {
        super.visitCode();
        super.visitLdcInsn(fullMethodName);
        super.visitMethodInsn(INVOKESTATIC, "io/fabric8/apmagent/ApmAgent",
                                 "enterMethod", "(Ljava/lang/String;)V", false);
    }

    @Override
    public void visitInsn(int opcode) {
        if ((opcode >= IRETURN && opcode <= RETURN) || opcode == ATHROW) {
            super.visitLdcInsn(fullMethodName);
            super.visitMethodInsn(INVOKESTATIC, "io/fabric8/apmagent/ApmAgent",
                                     "exitMethod", "(Ljava/lang/String;)V", false);
        }
        super.visitInsn(opcode);
    }
}