com.marklogic.client.io.JacksonDatabindHandle Maven / Gradle / Ivy
/*
* 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.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.marklogic.client.MarkLogicIOException;
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.JSONReadHandle;
import com.marklogic.client.io.marker.JSONWriteHandle;
import com.marklogic.client.io.marker.StructureReadHandle;
import com.marklogic.client.io.marker.StructureWriteHandle;
import com.marklogic.client.io.marker.TextReadHandle;
import com.marklogic.client.io.marker.TextWriteHandle;
import com.marklogic.client.io.marker.XMLReadHandle;
import com.marklogic.client.io.marker.XMLWriteHandle;
import com.marklogic.client.impl.JacksonBaseHandle;
/**
* An adapter for using the Jackson Open Source library for JSON; represents
* JSON content for reading or writing as objects of the specified POJO class.
* Enables reading and writing JSON directly to or from POJOs.
*/
public class JacksonDatabindHandle
extends JacksonBaseHandle
implements ContentHandle,
OutputStreamSender, BufferableHandle,
JSONReadHandle, JSONWriteHandle,
TextReadHandle, TextWriteHandle,
XMLReadHandle, XMLWriteHandle,
StructureReadHandle, StructureWriteHandle
{
private Class contentClass;
private T content;
/**
* Creates a factory to create a JacksonDatabindHandle instance for POJO instances
* of the specified classes.
* @param pojoClasses the POJO classes for which this factory provides a handle
* @return the factory
*/
static public ContentHandleFactory newFactory(Class... pojoClasses) {
if (pojoClasses == null || pojoClasses.length == 0) return null;
return new JacksonDatabindHandleFactory(pojoClasses);
}
/**
* Creates a factory to create a JacksonDatabindHandle instance for POJO instances
* of the specified classes.
* @param mapper the Jackson ObjectMapper for marshaling the POJO classes
* @param pojoClasses the POJO classes for which this factory provides a handle
* @return the factory
*/
static public ContentHandleFactory newFactory(ObjectMapper mapper, Class... pojoClasses) {
if (mapper == null || pojoClasses == null || pojoClasses.length == 0) return null;
return new JacksonDatabindHandleFactory(mapper, pojoClasses);
}
/**
* Specify the type of content this JacksonDatabindHandle will manage.
*
* @param contentClass the class of your custom POJO for databinding
*/
public JacksonDatabindHandle(Class contentClass) {
super();
this.contentClass = contentClass;
setResendable(true);
}
/**
* Provides a handle on POJO content.
* @param content the POJO which should be serialized
*/
public JacksonDatabindHandle(T content) {
this((Class) content.getClass());
set(content);
}
/**
* Specifies the format of the content and returns the handle
* as a fluent convenience.
* @param format the format of the content
* @return this handle
*/
public JacksonDatabindHandle withFormat(Format format) {
setFormat(format);
return this;
}
/**
* Returns the content.
* @return the content you provided if you called {@link #JacksonDatabindHandle(Object)}
* or {@link #set(Object)} or if the content is being de-serialized, a pojo of
* the specified type populated with the data
*/
@Override
public T get() {
return content;
}
/**
* Assigns your custom POJO as the content.
* @param content your custom POJO
*/
@Override
public void set(T content) {
this.content = content;
}
/**
* Assigns a your custom POJO as the content and returns the handle.
* @param content your custom POJO
* @return the handle
*/
public JacksonDatabindHandle with(T content) {
set(content);
return this;
}
/**
* Provides access to the ObjectMapper used internally so you can configure
* it to fit your JSON.
* @return the ObjectMapper instance
*/
@Override
public ObjectMapper getMapper() { return super.getMapper(); }
/**
* Enables clients to specify their own ObjectMapper instance, including databinding mappers
* for formats other than JSON.
* For example:{@code
*ObjectMapper mapper = new CsvMapper();
*mapper.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false);
*mapper.configure(JsonParser.Feature.AUTO_CLOSE_SOURCE, false);
*handle.setMapper(mapper);
* }
*
* Use at your own risk! Note that you most likely want to set to false the two options we
* demonstrate above (JsonGenerator.Feature.AUTO_CLOSE_TARGET and JsonParser.Feature.AUTO_CLOSE_SOURCE)
* as we do so your mapper will not close streams which we may need to reuse if we have to
* resend a network request.
**/
@Override
public void setMapper(ObjectMapper mapper) { super.setMapper(mapper); }
@Override
protected void receiveContent(InputStream content) {
if (content == null)
return;
try {
this.content = (T) getMapper().readValue(
new InputStreamReader(content, "UTF-8"), contentClass);
} catch (JsonParseException e) {
throw new MarkLogicIOException(e);
} catch (JsonMappingException e) {
throw new MarkLogicIOException(e);
} catch (IOException e) {
throw new MarkLogicIOException(e);
} finally {
try {
content.close();
} catch (IOException e) {
// ignore.
}
}
}
@Override
protected boolean hasContent() {
return content != null;
}
@Override
public void write(OutputStream out) throws IOException {
getMapper().writeValue(new OutputStreamWriter(out, "UTF-8"), get());
}
static private class JacksonDatabindHandleFactory implements ContentHandleFactory {
private Class[] contentClasses;
private ObjectMapper mapper = null;
private Set> classSet;
private JacksonDatabindHandleFactory(Class... contentClasses) {
this(null, contentClasses);
}
private JacksonDatabindHandleFactory(ObjectMapper mapper, Class... contentClasses) {
super();
this.contentClasses = contentClasses;
this.mapper = mapper;
this.classSet = new HashSet>(Arrays.asList(contentClasses));
}
@Override
public Class[] getHandledClasses() {
return contentClasses;
}
@Override
public boolean isHandled(Class type) {
return classSet.contains(type);
}
@Override
public ContentHandle newHandle(Class type) {
if ( ! isHandled(type) ) return null;
JacksonDatabindHandle handle = new JacksonDatabindHandle(type);
if ( mapper != null ) handle.setMapper(mapper);
return handle;
}
}
}