# JsonXMLInputFactory.java

    /*
     * Copyright 2011, 2012 Odysseus Software GmbH
     *
     * 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.apache.synapse.commons.staxon.core.json;

    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.Reader;
    import java.io.UnsupportedEncodingException;
    import java.util.Arrays;

    import javax.xml.namespace.QName;
    import javax.xml.stream.EventFilter;
    import javax.xml.stream.FactoryConfigurationError;
    import javax.xml.stream.XMLEventReader;
    import javax.xml.stream.XMLReporter;
    import javax.xml.stream.XMLResolver;
    import javax.xml.stream.XMLStreamException;
    import javax.xml.stream.XMLStreamReader;

    import org.apache.synapse.commons.staxon.core.base.AbstractXMLInputFactory;
    import org.apache.synapse.commons.staxon.core.event.SimpleXMLEventReader;
    import org.apache.synapse.commons.staxon.core.event.SimpleXMLFilteredEventReader;
    import org.apache.synapse.commons.staxon.core.json.stream.JsonStreamFactory;
    import org.apache.synapse.commons.staxon.core.json.stream.JsonStreamSource;
    import org.apache.synapse.commons.staxon.core.json.stream.impl.Constants;
    import org.apache.synapse.commons.staxon.core.json.stream.util.AddRootSource;

    /**
     * XML input factory for streaming from JSON.
     */
    public class JsonXMLInputFactory extends AbstractXMLInputFactory {
        /**
         * <p>Whether to use the {@link JsonXMLStreamConstants#MULTIPLE_PI_TARGET}
         * processing instruction to indicate an array start.
         * If <code>true</code>, this reader will insert a PI with the field
         * name as PI data.
         * <p/>
         * <p>Note that the element given in the PI may occur zero times,
         * indicating an "empty array".</p>
         * <p/>
         * <p>The default value is <code>true</code>.</p>
         */
        public static final String PROP_MULTIPLE_PI = "JsonXMLInputFactory.multiplePI";

        /**
         * <p>JSON documents may have have multiple root properties. However,
         * XML requires a single root element. This property takes the name
         * of a "virtual" root element, which will be added to the stream
         * when reading.</p>
         * <p/>
         * <p>The default value is <code>null</code>.</p>
         */
        public static final String PROP_VIRTUAL_ROOT = "JsonXMLInputFactory.virtualRoot";

        /**
         * <p>Namespace prefix separator.</p>
         * <p/>
         * <p>The default value is <code>':'</code>.</p>
         */
        public static final String PROP_NAMESPACE_SEPARATOR = "JsonXMLInputFactory.namespaceSeparator";

        private final JsonStreamFactory streamFactory;

        private boolean multiplePI;
        private QName virtualRoot;
        private char namespaceSeparator;
        private boolean xmlNilReadWriteEnabled;

        public JsonXMLInputFactory() throws FactoryConfigurationError {
            this(JsonXMLConfig.DEFAULT);
        }

        public JsonXMLInputFactory(JsonStreamFactory streamFactory) {
            this(JsonXMLConfig.DEFAULT, streamFactory);
        }

        public JsonXMLInputFactory(JsonXMLConfig config) throws FactoryConfigurationError {
            this(config, JsonStreamFactory.newFactory());
        }

        public JsonXMLInputFactory(JsonXMLConfig config, JsonStreamFactory streamFactory) {
            this.multiplePI = config.isMultiplePI();
            this.virtualRoot = config.getVirtualRoot();
            this.namespaceSeparator = config.getNamespaceSeparator();
            this.streamFactory = streamFactory;
            this.xmlNilReadWriteEnabled = config.isReadWriteXmlNil();

    		/*
    		 * initialize standard properties
    		 */
            super.setProperty(IS_COALESCING, Boolean.TRUE);
            super.setProperty(IS_NAMESPACE_AWARE, Boolean.TRUE);
            super.setProperty(IS_REPLACING_ENTITY_REFERENCES, Boolean.TRUE);
            super.setProperty(IS_SUPPORTING_EXTERNAL_ENTITIES, Boolean.FALSE);
            super.setProperty(IS_VALIDATING, Boolean.FALSE);
            super.setProperty(SUPPORT_DTD, Boolean.FALSE);
        }

        private JsonStreamSource decorate(JsonStreamSource source) {
            if (virtualRoot != null) {
                source = new AddRootSource(source, virtualRoot, namespaceSeparator);
            }
            return source;
        }

        @Override
        public JsonXMLStreamReader createXMLStreamReader(InputStream stream, String encoding) throws XMLStreamException {
            try {
                return createXMLStreamReader(new InputStreamReader(stream, encoding));
            } catch (UnsupportedEncodingException e) {
                throw new XMLStreamException(e);
            }
        }

        @Override
        public JsonXMLStreamReader createXMLStreamReader(String systemId, InputStream stream) throws XMLStreamException {
            return createXMLStreamReader(stream);
        }

        @Override
        public JsonXMLStreamReader createXMLStreamReader(String systemId, Reader reader) throws XMLStreamException {
            return createXMLStreamReader(reader);
        }

        @Override
        public JsonXMLStreamReader createXMLStreamReader(Reader reader) throws XMLStreamException {
            try {
                return new JsonXMLStreamReader(decorate(streamFactory.createJsonStreamSource(reader)), multiplePI,
                        namespaceSeparator, xmlNilReadWriteEnabled);
            } catch (IOException e) {
                throw new XMLStreamException(e);
            }
        }

        public JsonXMLStreamReader createXMLStreamReader(Reader reader, Constants.SCANNER scanner) throws XMLStreamException {
            try {
                return new JsonXMLStreamReader(decorate(streamFactory.createJsonStreamSource(reader, scanner)), multiplePI,
                        namespaceSeparator, xmlNilReadWriteEnabled);
            } catch (IOException e) {
                throw new XMLStreamException(e);
            }
        }

        @Override
        public JsonXMLStreamReader createXMLStreamReader(InputStream stream) throws XMLStreamException {
            try {
                return new JsonXMLStreamReader(decorate(streamFactory.createJsonStreamSource(stream)), multiplePI,
                        namespaceSeparator, xmlNilReadWriteEnabled);
            } catch (IOException e) {
                throw new XMLStreamException(e);
            }
        }

        public JsonXMLStreamReader createXMLStreamReader(InputStream stream, Constants.SCANNER scanner) throws XMLStreamException {
            try {
                return new JsonXMLStreamReader(decorate(streamFactory.createJsonStreamSource(stream, scanner)), multiplePI,
                        namespaceSeparator, xmlNilReadWriteEnabled);
            } catch (IOException e) {
                throw new XMLStreamException(e);
            }
        }

        @Override
        public XMLEventReader createXMLEventReader(XMLStreamReader reader) throws XMLStreamException {
            if (getEventAllocator() == null) {
                return new SimpleXMLEventReader(reader);
            } else {
                return new SimpleXMLEventReader(reader, getEventAllocator().newInstance());
            }
        }

        @Override
        public XMLEventReader createFilteredReader(XMLEventReader reader, EventFilter filter) throws XMLStreamException {
            return new SimpleXMLFilteredEventReader(reader, filter);
        }

        @Override
        public void setXMLResolver(XMLResolver resolver) {
            throw new UnsupportedOperationException();
        }

        @Override
        public void setXMLReporter(XMLReporter reporter) {
            throw new UnsupportedOperationException();
        }

        @Override
        public boolean isPropertySupported(String name) {
            return super.isPropertySupported(name)
                    || Arrays.asList(PROP_MULTIPLE_PI, PROP_VIRTUAL_ROOT, PROP_NAMESPACE_SEPARATOR).contains(name);
        }

        @Override
        public Object getProperty(String name) throws IllegalArgumentException {
            if (super.isPropertySupported(name)) {
                return super.getProperty(name);
            } else { // proprietary properties
                if (PROP_MULTIPLE_PI.equals(name)) {
                    return Boolean.valueOf(multiplePI);
                } else if (PROP_VIRTUAL_ROOT.equals(name)) {
                    return virtualRoot;
                } else if (PROP_NAMESPACE_SEPARATOR.equals(name)) {
                    return namespaceSeparator;
                } else {
                    throw new IllegalArgumentException("Unsupported property: " + name);
                }
            }
        }

        @Override
        public void setProperty(String name, Object value) throws IllegalArgumentException {
            if (IS_NAMESPACE_AWARE.equals(name)) {
                if (!getProperty(name).equals(value)) {
                    throw new IllegalArgumentException("Cannot change property: " + name);
                }
            } else if (IS_REPLACING_ENTITY_REFERENCES.equals(name)) {
                if (!getProperty(name).equals(value)) {
                    throw new IllegalArgumentException("Cannot change property: " + name);
                }
            } else if (IS_SUPPORTING_EXTERNAL_ENTITIES.equals(name)) {
                if (!getProperty(name).equals(value)) {
                    throw new IllegalArgumentException("Cannot change property: " + name);
                }
            } else if (IS_VALIDATING.equals(name)) {
                if (!getProperty(name).equals(value)) {
                    throw new IllegalArgumentException("Cannot change property: " + name);
                }
            } else if (SUPPORT_DTD.equals(name)) {
                if (!getProperty(name).equals(value)) {
                    throw new IllegalArgumentException("Cannot change property: " + name);
                }
            } else if (super.isPropertySupported(name)) {
                super.setProperty(name, value);
            } else { // proprietary properties
                if (PROP_MULTIPLE_PI.equals(name)) {
                    multiplePI = ((Boolean) value).booleanValue();
                } else if (PROP_VIRTUAL_ROOT.equals(name)) {
                    virtualRoot = value instanceof String ? QName.valueOf((String) value) : (QName) value;
                } else if (PROP_NAMESPACE_SEPARATOR.equals(name)) {
                    namespaceSeparator = (Character) value;
                } else {
                    throw new IllegalArgumentException("Unsupported property: " + name);
                }
            }
        }
    }