org.eclipse.wb.internal.swt.model.layout.LayoutJavaInfoParticipator.java Source code

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Here is the source code for org.eclipse.wb.internal.swt.model.layout.LayoutJavaInfoParticipator.java

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/*******************************************************************************
 * Copyright (c) 2011 Google, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Google, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.wb.internal.swt.model.layout;

import org.eclipse.wb.core.model.IJavaInfoInitializationParticipator;
import org.eclipse.wb.core.model.JavaInfo;
import org.eclipse.wb.core.model.ObjectInfo;
import org.eclipse.wb.core.model.broadcast.ObjectInfoChildAddAfter;
import org.eclipse.wb.internal.core.model.util.surround.SurroundSupport;
import org.eclipse.wb.internal.core.utils.execution.ExecutionUtils;
import org.eclipse.wb.internal.core.utils.execution.RunnableObjectEx;
import org.eclipse.wb.internal.core.utils.reflect.ReflectionUtils;

import org.apache.commons.lang.StringUtils;

/**
 * {@link IJavaInfoInitializationParticipator} that performs name-based binding of
 * {@link LayoutInfo} and related artifacts.
 * <p>
 * For example it binds {@link LayoutInfo} with its {@link SurroundSupport}, that should be in same
 * package and have <code>"_SurroundSupport"</code> suffix.
 * 
 * @author scheglov_ke
 * @coverage swt.model.layout
 */
public class LayoutJavaInfoParticipator implements IJavaInfoInitializationParticipator {
    ////////////////////////////////////////////////////////////////////////////
    //
    // Instance
    //
    ////////////////////////////////////////////////////////////////////////////
    public static final Object INSTANCE = new LayoutJavaInfoParticipator();

    private LayoutJavaInfoParticipator() {
    }

    ////////////////////////////////////////////////////////////////////////////
    //
    // IJavaInfoInitializationParticipator
    //
    ////////////////////////////////////////////////////////////////////////////
    public void process(final JavaInfo javaInfo) throws Exception {
        if (javaInfo instanceof LayoutInfo) {
            final LayoutInfo layout = (LayoutInfo) javaInfo;
            // perform bindings...
            if (layout.getParent() != null) {
                // ...right now, if Layout already bound to its container
                performBindings(layout);
            } else {
                // ...or later, when Layout will be bound to its container
                layout.addBroadcastListener(new ObjectInfoChildAddAfter() {
                    public void invoke(ObjectInfo parent, ObjectInfo child) throws Exception {
                        if (child == layout) {
                            layout.removeBroadcastListener(this);
                            performBindings(layout);
                        }
                    }
                });
            }
        }
    }

    ////////////////////////////////////////////////////////////////////////////
    //
    // Bindings
    //
    ////////////////////////////////////////////////////////////////////////////
    /**
     * Performs artifacts bindings after building components tree.
     */
    private void performBindings(LayoutInfo layout) throws Exception {
        // bind SurroundSupport
        run(layout, new IBindingProcessor() {
            public boolean run(LayoutInfo layout, ClassLoader classLoader, Class<?> layoutClass, String layoutName)
                    throws Exception {
                String surroundClassName = layoutName + "SurroundSupport";
                Class<?> surroundClass = classLoader.loadClass(surroundClassName);
                ReflectionUtils.getConstructor(surroundClass, layoutClass).newInstance(layout);
                return true;
            }
        });
    }

    ////////////////////////////////////////////////////////////////////////////
    //
    // Utils
    //
    ////////////////////////////////////////////////////////////////////////////
    /**
     * The processor to use with {@link LayoutJavaInfoParticipator#run(LayoutInfo, IBindingProcessor)}
     * .
     */
    private interface IBindingProcessor {
        boolean run(LayoutInfo layout, ClassLoader classLoader, Class<?> layoutClass, String layoutName)
                throws Exception;
    }

    /**
     * Uses {@link IBindingProcessor} to attempt to perform binding by class of {@link LayoutInfo} and
     * any of its super classes. Trick is that sometimes artifact is bound not to the exact class of
     * {@link LayoutInfo}, but to some of its super classes, so we should check them too.
     */
    private static void run(final LayoutInfo layout, final IBindingProcessor processor) {
        Class<?> layoutClass = layout.getClass();
        for (; layoutClass != null; layoutClass = layoutClass.getSuperclass()) {
            final Class<?> finalLayoutClass = layoutClass;
            boolean success = ExecutionUtils.runObjectIgnore(new RunnableObjectEx<Boolean>() {
                public Boolean runObject() throws Exception {
                    run(layout, processor, finalLayoutClass);
                    return true;
                }
            }, false);
            if (success) {
                return;
            }
        }
    }

    private static void run(LayoutInfo layout, IBindingProcessor processor, Class<?> layoutClass) throws Exception {
        // prepare name of Layout without "Info" suffix
        final String layoutName;
        {
            String layoutClassName = layoutClass.getName();
            layoutName = StringUtils.removeEnd(layoutClassName, "Info");
        }
        // try to bind
        ClassLoader classLoader = ReflectionUtils.getClassLoader(layoutClass);
        processor.run(layout, classLoader, layoutClass, layoutName);
    }
}