org.pentaho.di.ui.core.dialog.DisplayInvocationHandler.java Source code

Introduction

Here is the source code for org.pentaho.di.ui.core.dialog.DisplayInvocationHandler.java

Source

/*! ******************************************************************************
 *
 * Pentaho Data Integration
 *
 * Copyright (C) 2002-2014 by Pentaho : http://www.pentaho.com
 *
 *******************************************************************************
 *
 * 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.pentaho.di.ui.core.dialog;

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

import org.apache.commons.lang.ClassUtils;
import org.eclipse.swt.widgets.Display;
import org.pentaho.di.core.logging.LogChannelInterface;

public class DisplayInvocationHandler<T> implements InvocationHandler {
    private final Display display;
    private final T delegate;
    private final LogChannelInterface log;
    private final boolean asyncForVoid;

    private class ResultHolder {
        private volatile Throwable throwable = null;
        private volatile Object result = null;
    }

    @SuppressWarnings("unchecked")
    public static <T> T forObject(Class<T> iface, T delegate, Display display, LogChannelInterface log,
            boolean asyncForVoid) {
        return (T) Proxy.newProxyInstance(delegate.getClass().getClassLoader(),
                (Class<?>[]) ClassUtils.getAllInterfaces(delegate.getClass()).toArray(new Class<?>[] {}),
                new DisplayInvocationHandler<T>(display, delegate, log, asyncForVoid));
    }

    public DisplayInvocationHandler(Display display, T delegate, LogChannelInterface log, boolean asyncForVoid) {
        this.display = display;
        this.delegate = delegate;
        this.log = log;
        this.asyncForVoid = asyncForVoid;
    }

    @Override
    public Object invoke(Object proxy, final Method method, final Object[] args) throws Throwable {
        if (display.getThread() == Thread.currentThread()) {
            try {
                return method.invoke(delegate, args);
            } catch (InvocationTargetException e) {
                throw e.getCause();
            }
        }
        if (asyncForVoid && method.getReturnType().equals(Void.TYPE)) {
            display.asyncExec(new Runnable() {

                @Override
                public void run() {
                    try {
                        method.invoke(delegate, args);
                    } catch (Throwable e) {
                        if (e instanceof InvocationTargetException) {
                            e = e.getCause();
                        }
                        log.logError(e.getMessage(), e);
                    }
                }
            });
            return null;
        }
        final ResultHolder resultHolder = new ResultHolder();
        display.syncExec(new Runnable() {

            @Override
            public void run() {
                try {
                    resultHolder.result = method.invoke(delegate, args);
                } catch (InvocationTargetException e) {
                    resultHolder.throwable = e.getCause();
                } catch (Exception e) {
                    resultHolder.throwable = e;
                }
            }
        });
        if (resultHolder.result != null) {
            return resultHolder.result;
        } else {
            throw resultHolder.throwable;
        }
    }

}