com.google.inject.internal.DelegatingInvocationHandler Maven / Gradle / Ivy

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package com.google.inject.internal;

import com.google.common.base.Preconditions;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

class DelegatingInvocationHandler implements InvocationHandler {

    private volatile boolean initialized;

    private T delegate;

    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {
        try {
            // checking volatile field for synchronization
            Preconditions.checkState(initialized,
                    "This is a proxy used to support"
                            + " circular references. The object we're"
                            + " proxying is not constructed yet. Please wait until after"
                            + " injection has completed to use this object.");
            Preconditions.checkNotNull(delegate,
                    "This is a proxy used to support"
                            + " circular references. The object we're "
                            + " proxying is initialized to null."
                            + " No methods can be called.");

            return method.invoke(delegate, args);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        } catch (IllegalArgumentException e) {
            throw new RuntimeException(e);
        } catch (InvocationTargetException e) {
            throw e.getTargetException();
        }
    }

    void setDelegate(T delegate) {
        this.delegate = delegate;
        initialized = true;
    }
}