com.marklogic.client.extra.xom.XOMHandle Maven / Gradle / Ivy

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/*
 * Copyright 2012-2016 MarkLogic Corporation
 *
 * 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 com.marklogic.client.extra.xom;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.ParsingException;
import nu.xom.Serializer;
import nu.xom.ValidityException;

import com.marklogic.client.MarkLogicIOException;
import com.marklogic.client.io.BaseHandle;
import com.marklogic.client.io.Format;
import com.marklogic.client.io.OutputStreamSender;
import com.marklogic.client.io.marker.BufferableHandle;
import com.marklogic.client.io.marker.ContentHandle;
import com.marklogic.client.io.marker.ContentHandleFactory;
import com.marklogic.client.io.marker.StructureReadHandle;
import com.marklogic.client.io.marker.StructureWriteHandle;
import com.marklogic.client.io.marker.XMLReadHandle;
import com.marklogic.client.io.marker.XMLWriteHandle;

/**
 * A XOM Handle represents XML content as a XOM document for reading or writing.
 * You must install the XOM library to use this class.
 */
public class XOMHandle
	extends BaseHandle
    implements OutputStreamSender, BufferableHandle, ContentHandle,
    	XMLReadHandle, XMLWriteHandle,
    	StructureReadHandle, StructureWriteHandle
{
	private Document content;
	private Builder  builder;

	/**
	 * Creates a factory to create a XOMHandle instance for a XOM document.
	 * @return	the factory
	 */
	static public ContentHandleFactory newFactory() {
		return new ContentHandleFactory() {
			@Override
			public Class[] getHandledClasses() {
				return new Class[]{ Document.class };
			}
			@Override
			public boolean isHandled(Class type) {
				return Document.class.isAssignableFrom(type);
			}
			@Override
			public  ContentHandle newHandle(Class type) {
				@SuppressWarnings("unchecked")
				ContentHandle handle = isHandled(type) ?
						(ContentHandle) new XOMHandle() : null;
				return handle;
			}
		};
	}

	/**
	 * Zero-argument constructor.
	 */
	public XOMHandle() {
		super();
		super.setFormat(Format.XML);
   		setResendable(true);
	}
	/**
	 * Provides a handle on XML content as a XOM document structure.
	 * @param content	the XML document.
	 */
	public XOMHandle(Document content) {
		this();
    	set(content);
	}

	/**
	 * Returns the XOM structure builder for XML content.
	 * @return	the XOM builder.
	 */
	public Builder getBuilder() {
		if (builder == null)
			builder = makeBuilder();
		return builder;
	}
	/**
	 * Specifies a XOM structure builder for XML content.
	 * @param builder	the XOM builder.
	 */
	public void setBuilder(Builder builder) {
		this.builder = builder;
	}
	protected Builder makeBuilder() {
		return new Builder(false);
	}

	/**
	 * Returns the XML document structure.
	 * @return	the XML document.
	 */
	@Override
	public Document get() {
		return content;
	}
	/**
	 * Assigns an XML document structure as the content.
	 * @param content	the XML document.
	 */
    @Override
	public void set(Document content) {
    	this.content = content;
    }
	/**
	 * Assigns an XML document structure as the content and returns the handle.
	 * @param content	the XML document.
	 * @return	the handle on the XML document.
	 */
    public XOMHandle with(Document content) {
    	set(content);
    	return this;
    }

	/**
	 * Restricts the format to XML.
	 */
	@Override
	public void setFormat(Format format) {
		if (format != Format.XML)
			throw new IllegalArgumentException("XOMHandle supports the XML format only");
	}

	@Override
	public void fromBuffer(byte[] buffer) {
		if (buffer == null || buffer.length == 0)
			content = null;
		else
			receiveContent(new ByteArrayInputStream(buffer));
	}
	@Override
	public byte[] toBuffer() {
		try {
			if (content == null)
				return null;

			ByteArrayOutputStream buffer = new ByteArrayOutputStream();
			write(buffer);

			return buffer.toByteArray();
		} catch (IOException e) {
			throw new MarkLogicIOException(e);
		}
	}

	/**
	 * Returns the XML document as a string.
	 */
	@Override
	public String toString() {
		try {
			return new String(toBuffer(),"UTF-8");
		} catch (UnsupportedEncodingException e) {
			throw new MarkLogicIOException(e);
		}
	}

	@Override
	protected Class receiveAs() {
		return InputStream.class;
	}
	@Override
	protected void receiveContent(InputStream content) {
		if (content == null)
			return;

		try {
			this.content = getBuilder().build(
					new InputStreamReader(content, "UTF-8")
					);
		} catch (ValidityException e) {
			throw new MarkLogicIOException(e);
		} catch (ParsingException e) {
			throw new MarkLogicIOException(e);
		} catch (IOException e) {
			throw new MarkLogicIOException(e);
		} finally {
			try {
				content.close();
			} catch (IOException e) {
				// ignore.
			}
		}
	}

	@Override
	protected OutputStreamSender sendContent() {
		if (content == null) {
			throw new IllegalStateException("No document to write");
		}

		return this;
	}
	@Override
	public void write(OutputStream out) throws IOException {
		makeSerializer(out).write(content);
	}
	protected Serializer makeSerializer(OutputStream out) throws UnsupportedEncodingException {
		return new Serializer(out, "UTF-8");
	}
}