org.greencheek.gc.memusage.agent.RecordGCMemUsageAnnotationCollector.java Source code

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Here is the source code for org.greencheek.gc.memusage.agent.RecordGCMemUsageAnnotationCollector.java

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/*
Copyright 2012 Dominic Tootell
    
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 org.greencheek.gc.memusage.agent;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * Visitor implementation to collect field annotation information from class.
 */
public class RecordGCMemUsageAnnotationCollector extends ClassVisitor {
    private final Map<String, MethodInfo> matchingMethods = new ConcurrentHashMap<String, MethodInfo>();
    private final String className;
    private volatile boolean cinitAvailable = false;

    public RecordGCMemUsageAnnotationCollector(String className) {
        super(Opcodes.ASM4);
        this.className = className;
    }

    public Map<String, MethodInfo> getMethods() {
        return matchingMethods;
    }

    public boolean hasCinit() {
        return cinitAvailable;
    }

    /**
     * Creates the signature used to create the static fields later on.
     * 
     * @param access
     * @param name
     * @param desc
     * @param signature
     * @param exceptions
     * @return
     */
    private MethodInfo createMatchingMethod(int access, String name, String desc, String signature,
            String[] exceptions, String fieldName, String annotatedClassName) {
        MethodInfo info = new MethodInfo(access, name, desc, signature, exceptions, fieldName, annotatedClassName);
        matchingMethods.put(info.toString(), info);
        return info;

    }

    @Override
    public MethodVisitor visitMethod(final int access, final String name, final String desc, final String signature,
            final String[] exceptions) {

        if ("<clinit>".equals(name)) {
            cinitAvailable = true;
        }

        return new MethodVisitor(Opcodes.ASM4) {

            @Override
            public AnnotationVisitor visitAnnotation(final String sig, boolean visible) {
                if (sig.equals("Lorg/greencheek/gc/memusage/agent/RecordGCMemUsage;")) {

                    return new AnnotationVisitor(Opcodes.ASM4) {
                        private String fieldName = name;

                        public void visit(String name, Object value) {
                            if (name.equals("fieldName"))
                                fieldName = value.toString();
                        }

                        @Override
                        public void visitEnd() {
                            if (sig.equals("Lorg/greencheek/gc/memusage/agent/RecordGCMemUsage;")) {
                                createMatchingMethod(access, name, desc, signature, exceptions, fieldName,
                                        className);
                            }
                            super.visitEnd();
                        }

                    };
                } else {
                    return null;
                }
            }

        };
    }
}