org.apache.olingo.fit.utils.v4.XMLUtilities.java Source code

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Here is the source code for org.apache.olingo.fit.utils.v4.XMLUtilities.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.olingo.fit.utils.v4;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLEventReader;
import org.apache.commons.io.IOUtils;
import org.apache.olingo.fit.utils.Accept;
import org.apache.olingo.fit.utils.Commons;
import org.apache.olingo.fit.utils.Constants;
import org.apache.olingo.fit.utils.MetadataLinkInfo;
import org.apache.olingo.fit.utils.ODataVersion;
import org.apache.olingo.fit.utils.XmlElement;

public class XMLUtilities extends org.apache.olingo.fit.utils.AbstractXMLUtilities {

    public XMLUtilities() throws Exception {
        super(ODataVersion.v4);
    }

    @Override
    public void retrieveLinkInfoFromMetadata() throws Exception {

        final MetadataLinkInfo metadataLinkInfo = new MetadataLinkInfo();
        Commons.getLinkInfo().put(version, metadataLinkInfo);

        final InputStream metadata = fsManager.readFile(Constants.METADATA, Accept.XML);

        final ByteArrayOutputStream bos = new ByteArrayOutputStream();
        IOUtils.copy(metadata, bos);
        IOUtils.closeQuietly(metadata);

        XMLEventReader reader = getEventReader(new ByteArrayInputStream(bos.toByteArray()));

        final Set<String> singletons = new HashSet<String>();

        try {
            while (true) {
                final Map.Entry<Integer, XmlElement> entitySetElement = extractElement(reader, null,
                        Collections.<String>singletonList("Singleton"), null, false, 0, -1, -1);

                final String entitySetName = entitySetElement.getValue().getStart()
                        .getAttributeByName(new QName("Name")).getValue().trim();
                singletons.add(entitySetName);
            }
        } catch (Exception e) {
        } finally {
            reader.close();
        }

        reader = getEventReader(new ByteArrayInputStream(bos.toByteArray()));

        try {
            while (true) {
                final Map.Entry<Integer, XmlElement> entitySetElement = extractElement(reader, null,
                        Collections.<String>singletonList("EntitySet"), null, false, 0, -1, -1);

                retrieveLinks(entitySetElement.getValue(), metadataLinkInfo, singletons);
            }
        } catch (Exception e) {
        } finally {
            reader.close();
        }

        reader = getEventReader(new ByteArrayInputStream(bos.toByteArray()));

        try {
            while (true) {
                final Map.Entry<Integer, XmlElement> entitySetElement = extractElement(reader, null,
                        Collections.<String>singletonList("Singleton"), null, false, 0, -1, -1);

                retrieveLinks(entitySetElement.getValue(), metadataLinkInfo, singletons);
            }
        } catch (Exception e) {
        } finally {
            reader.close();
        }
    }

    private void retrieveLinks(final XmlElement entitySetElement, final MetadataLinkInfo metadataLinkInfo,
            final Set<String> singletons) throws Exception {

        final String entitySetName = entitySetElement.getStart().getAttributeByName(new QName("Name")).getValue()
                .trim();

        final XMLEventReader entityReader = entitySetElement.getContentReader();
        int size = 0;

        try {
            while (true) {
                final XmlElement navProperty = extractElement(entityReader, null,
                        Collections.<String>singletonList("NavigationPropertyBinding"), null, false, 0, -1, -1)
                                .getValue();

                final String linkName = navProperty.getStart().getAttributeByName(new QName("Path")).getValue();
                final String target = navProperty.getStart().getAttributeByName(new QName("Target")).getValue();
                final boolean feed = !singletons.contains(target);

                metadataLinkInfo.addLink(entitySetName, linkName, target, feed);

                size++;
            }
        } catch (Exception e) {
        } finally {
            entityReader.close();
        }

        if (size == 0) {
            metadataLinkInfo.addEntitySet(entitySetName);
        }
    }
}