com.liferay.portal.kernel.util.MethodKey.java Source code

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Here is the source code for com.liferay.portal.kernel.util.MethodKey.java

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/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 */

package com.liferay.portal.kernel.util;

import com.liferay.petra.string.StringPool;
import com.liferay.portal.kernel.io.Deserializer;
import com.liferay.portal.kernel.io.Serializer;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;

import java.lang.reflect.Method;

import java.nio.ByteBuffer;

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

/**
 * Provides a serializable loose representation for {@link Method}, considering
 * the declaring class, name, and parameter types of the {@link Method}, while
 * ignoring its return type and exceptions. This means the compiler generated
 * bridging method is considered logically the same as it source counterpart. On
 * deserialization for a generic {@link Method}, the {@link Method} that is
 * resolved (bridge method or source method) is runtime environment dependent.
 * Whether it is resolved to a bridge method or source method is of no
 * consequence, as a force cast is performed on the method's return value,
 * assuring the same result.
 *
 * @author Brian Wing Shun Chan
 * @author Shuyang Zhou
 */
public class MethodKey implements Externalizable {

    public static void resetCache() {
        _methods.clear();
    }

    /**
     * The empty constructor is required by {@link Externalizable}. Do not use
     * this for any other purpose.
     */
    public MethodKey() {
    }

    public MethodKey(Class<?> declaringClass, String methodName, Class<?>... parameterTypes) {

        _declaringClass = declaringClass;
        _methodName = methodName;
        _parameterTypes = parameterTypes;
    }

    public MethodKey(Method method) {
        this(method.getDeclaringClass(), method.getName(), method.getParameterTypes());
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (!(obj instanceof MethodKey)) {
            return false;
        }

        MethodKey methodKey = (MethodKey) obj;

        if ((_declaringClass == methodKey._declaringClass) && Objects.equals(_methodName, methodKey._methodName)
                && Arrays.equals(_parameterTypes, methodKey._parameterTypes)) {

            return true;
        }

        return false;
    }

    public Class<?> getDeclaringClass() {
        return _declaringClass;
    }

    public Method getMethod() throws NoSuchMethodException {
        Method method = _methods.get(this);

        if (method == null) {
            method = _declaringClass.getDeclaredMethod(_methodName, _parameterTypes);

            _methods.put(this, method);
        }

        method.setAccessible(true);

        return method;
    }

    public String getMethodName() {
        return _methodName;
    }

    public Class<?>[] getParameterTypes() {
        return _parameterTypes;
    }

    @Override
    public int hashCode() {

        // Using the same hash algorithm as java.lang.reflect.Method

        String declaringClassName = _declaringClass.getName();

        return declaringClassName.hashCode() ^ _methodName.hashCode();
    }

    @Override
    public void readExternal(ObjectInput objectInput) throws ClassNotFoundException, IOException {

        int size = objectInput.readInt();

        byte[] data = new byte[size];

        objectInput.readFully(data);

        Deserializer deserializer = new Deserializer(ByteBuffer.wrap(data));

        _declaringClass = deserializer.readObject();
        _methodName = deserializer.readString();

        int parameterTypesLength = deserializer.readInt();

        _parameterTypes = new Class<?>[parameterTypesLength];

        for (int i = 0; i < parameterTypesLength; i++) {
            _parameterTypes[i] = deserializer.readObject();
        }
    }

    @Override
    public String toString() {
        if (_toString != null) {
            return _toString;
        }

        StringBundler sb = new StringBundler(4 + _parameterTypes.length * 2);

        sb.append(_declaringClass.getName());
        sb.append(StringPool.PERIOD);
        sb.append(_methodName);
        sb.append(StringPool.OPEN_PARENTHESIS);

        for (Class<?> parameterType : _parameterTypes) {
            sb.append(parameterType.getName());
            sb.append(StringPool.COMMA);
        }

        if (_parameterTypes.length != 0) {
            sb.setIndex(sb.index() - 1);
        }

        sb.append(StringPool.CLOSE_PARENTHESIS);

        _toString = sb.toString();

        return _toString;
    }

    public MethodKey transform(ClassLoader classLoader) throws ClassNotFoundException {

        Class<?> declaringClass = classLoader.loadClass(_declaringClass.getName());

        Class<?>[] parameterTypes = new Class<?>[_parameterTypes.length];

        for (int i = 0; i < _parameterTypes.length; i++) {
            parameterTypes[i] = classLoader.loadClass(_parameterTypes[i].getName());
        }

        return new MethodKey(declaringClass, _methodName, parameterTypes);
    }

    @Override
    public void writeExternal(ObjectOutput objectOutput) throws IOException {
        Serializer serializer = new Serializer();

        serializer.writeObject(_declaringClass);
        serializer.writeString(_methodName);
        serializer.writeInt(_parameterTypes.length);

        for (Class<?> parameterType : _parameterTypes) {
            serializer.writeObject(parameterType);
        }

        ByteBuffer byteBuffer = serializer.toByteBuffer();

        objectOutput.writeInt(byteBuffer.remaining());
        objectOutput.write(byteBuffer.array(), byteBuffer.position(), byteBuffer.remaining());
    }

    private static final Map<MethodKey, Method> _methods = new ConcurrentHashMap<>();
    private static final long serialVersionUID = 1L;

    private Class<?> _declaringClass;
    private String _methodName;
    private Class<?>[] _parameterTypes;

    // Transient cache

    private String _toString;

}