introducitons.IsModifiedMixin.java Source code

Introduction

Here is the source code for introducitons.IsModifiedMixin.java

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/*
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package introducitons;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.aop.support.DelegatingIntroductionInterceptor;

/**  @author igorm  */
public class IsModifiedMixin extends DelegatingIntroductionInterceptor implements IsModified {
    private volatile boolean modified = false;
    private final Map<Method, Method> methodCache = new HashMap<>();

    @Override
    protected Object doProceed(MethodInvocation mi) throws Throwable {
        return super.doProceed(mi); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public Object invoke(MethodInvocation mi) throws Throwable {
        showMI(mi);
        if (!isModified()) {
            if (methodStartWith(mi, "set") && mi.getArguments().length == 1) {
                Method getter;
                getter = getGetterFromSetter(mi.getMethod());

                if (null != getter) {
                    Object newVal = mi.getArguments()[0];
                    Object oldVal = getter.invoke(mi.getThis(), (Object[]) null);
                    if (newVal == null && oldVal == null) {
                        modified = false;
                    } else if ((newVal != null && oldVal == null) || (newVal == null && oldVal != null)) {
                        modified = true;
                    } else
                        modified = !newVal.equals(oldVal);
                }
            }
        }
        return super.invoke(mi);
    }

    private void showMI(MethodInvocation mi) {
        //      System.out.println("[Call invoke for method = " + mi.getMethod().getName() + "] modified = " + isModified());
    }

    private boolean methodStartWith(MethodInvocation mi, String substr) {
        return mi.getMethod().getName().startsWith(substr);
    }

    @Override
    public boolean isModified() {
        return modified;
    }

    private Method getGetterFromSetter(Method setter) {
        Method getter = methodCache.get(setter);
        if (null != getter) {
            return getter;
        }
        String getterName = setter.getName().replaceFirst("set", "get");
        try {
            getter = setter.getDeclaringClass().getMethod(getterName);
            synchronized (methodCache) {
                methodCache.put(setter, getter);
            }
            return getter;
        } catch (NoSuchMethodException ex) {
            return null;
        }
    }

    private Method getGetter(Method setter) {
        return getGetterFromSetter(setter);
    }
}