de.forsthaus.util.ZkossComponentTreeUtil.java Source code

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Here is the source code for de.forsthaus.util.ZkossComponentTreeUtil.java

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/**
 * Copyright 2010 the original author or authors.
 * 
 * This file is part of Zksample2. http://zksample2.sourceforge.net/
 *
 * Zksample2 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Zksample2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Zksample2.  If not, see <http://www.gnu.org/licenses/gpl.html>.
 */
package de.forsthaus.util;

import java.lang.reflect.Field;
import java.util.Iterator;
import java.util.Map;

import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang.StringUtils;
import org.zkoss.zk.ui.AbstractComponent;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.sys.ComponentsCtrl;

/**
 * Helper class for showing the zkoss component tree in the console for a root
 * component.
 * 
 * <pre>
 * Call it with:
 * System.out.println(ZkossComponentTreeUtil.getZulTree(aComponent));
 * </pre>
 * 
 * @author bbruhns
 * 
 */
public class ZkossComponentTreeUtil {

    final private static class FieldListener implements IAddListener {
        private final Field field;

        FieldListener(Field field) {
            super();
            this.field = field;
        }

        @Override
        public void addListener(Component component, StringBuilder result, int depth) {
            try {
                final Map<?, ?> m = (Map<?, ?>) this.field.get(component);
                if (m != null && !m.isEmpty()) {
                    for (final Map.Entry<?, ?> entry : m.entrySet()) {
                        result.append(StringUtils.leftPad("", depth << 2) + "  " + entry.getKey() + " -> "
                                + entry.getValue() + "\n");
                    }
                }
            } catch (final IllegalArgumentException e) {
            } catch (final IllegalAccessException e) {
            }
        }
    }

    private interface IAddListener {
        void addListener(Component component, StringBuilder result, int depth);
    }

    final private static IAddListener ADD_LISTENER;

    static {
        IAddListener tmp = null;
        try {
            final Field field;
            field = AbstractComponent.class.getDeclaredField("_listeners");
            field.setAccessible(true);
            tmp = new FieldListener(field);
        } catch (final SecurityException e) {
        } catch (final NoSuchFieldException e) {
        }

        if (tmp == null) {
            tmp = new IAddListener() {
                @Override
                public void addListener(Component component, StringBuilder result, int depth) {
                }
            };
        }

        ADD_LISTENER = tmp;
    }

    static public CharSequence getZulTree(Component component) {
        return new ZkossComponentTreeUtil().getZulTreeImpl(component);
    }

    private ZkossComponentTreeUtil() {
        super();
    }

    private CharSequence createCompName(Component component) {
        final StringBuilder sb = new StringBuilder();
        sb.append(component.getClass().getSimpleName());

        final String id = component.getId();
        if (StringUtils.isNotBlank(id) && !ComponentsCtrl.isAutoUuid(id)) {
            sb.append(" id=\"" + id + "\"");
        }
        return sb;
    }

    private CharSequence getZulTreeImpl(Component component) {
        if (component == null) {
            return "Component is null!";
        }

        final StringBuilder result = new StringBuilder(6000);
        return getZulTreeImpl(component, result, -1);
    }

    private StringBuilder getZulTreeImpl(Component component, StringBuilder result, int depth) {
        ++depth;
        final CharSequence id = createCompName(component);
        if (CollectionUtils.isEmpty(component.getChildren())) {
            result.append(StringUtils.leftPad("", depth << 2) + "<" + id + " />\n");
            return result;
        }

        result.append(StringUtils.leftPad("", depth << 2) + "<" + id + ">\n");

        ADD_LISTENER.addListener(component, result, depth);

        for (final Iterator<?> iterator = component.getChildren().iterator(); iterator.hasNext();) {
            getZulTreeImpl((Component) iterator.next(), result, depth);
        }

        result.append(StringUtils.leftPad("", depth << 2) + "<" + component.getClass().getSimpleName() + " />\n");
        return result;
    }

}