org.apache.isis.core.runtime.services.viewmodelsupport.ViewModelSupportDefault.java Source code

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Here is the source code for org.apache.isis.core.runtime.services.viewmodelsupport.ViewModelSupportDefault.java

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/**
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.apache.isis.core.runtime.services.viewmodelsupport;

import java.nio.charset.Charset;
import java.util.List;
import java.util.Set;

import com.google.common.base.Function;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.google.common.io.BaseEncoding;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import org.apache.isis.applib.services.viewmodelsupport.ViewModelSupport;

public class ViewModelSupportDefault implements ViewModelSupport {

    static class MementoDefault implements Memento {

        private Document doc;

        MementoDefault(Document doc) {
            this.doc = doc;
        }

        MementoDefault() {
            this(DocumentHelper.createDocument());
            doc.addElement("memento");
        }

        @Override
        public Memento set(String name, Object value) {
            final Element el = doc.getRootElement();
            Dom4jUtil.addChild(el, name, value);
            return this;
        }

        @Override
        public <T> T get(String name, Class<T> cls) {
            final Element el = doc.getRootElement();
            return Dom4jUtil.getChild(el, name, cls);
        }

        @Override
        public String asString() {
            final String xmlStr = Dom4jUtil.asString(doc);
            return BaseEncoding.base64Url().encode(xmlStr.getBytes(Charset.forName("UTF-8")));
        }

        private static final Function<Element, String> ELEMENT_NAME = new Function<Element, String>() {
            @Override
            public String apply(final Element input) {
                return input.getName();
            }
        };

        @Override
        public Set<String> keySet() {
            Element element = doc.getRootElement();
            List<Element> elements = element.elements();
            return Sets.newLinkedHashSet(Iterables.transform(elements, ELEMENT_NAME));
        }
    }

    @Override
    public Memento create() {
        return new MementoDefault();
    }

    @Override
    public Memento parse(String str) {
        final byte[] bytes = BaseEncoding.base64Url().decode(str);
        String xmlStr = new String(bytes, Charset.forName("UTF-8"));
        final Document doc = Dom4jUtil.parse(xmlStr);
        return new MementoDefault(doc);
    }

}