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This component provides an idemptotent idempotent repository, producers and consumers for Apache HBase.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-hbase</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

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Camel and HBase

When using a datasotre datastore inside a camel route, there is always the chalenge challenge of specifying how the camel message will stored to the datastore. In document based stores things are more easy as the message body can be directly mapped to a document. In relational databases an ORM solution can be used to map properties to columns etc. In column based stores things are more challenging as there is no standard way to perform that kind of mapping.

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The HBase component can be provided a custom HBaseConfiguration object as a property or it can create an HBase configuration object on its own based on the HBase related resources that are found on classpath.

    <bean id="hbase" class="org.apache.camel.component.hbase.HBaseComponent">
        <property name="configuration" ref="config"/>
    </bean>

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As mentioned above camel provides produers producer endpoints for HBase. This allows you to store, delete, retrieve or query data from HBase using your camel routes.

hbase://table[?options]

where table is the table name.

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Supported URI options on producer

{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{operation}} | {{CamelHBasePut}} | The HBase operation to perform. *Supported values*: {{CamelHBasePut}}, {{CamelHBaseGet}}, {{CamelHBaseDelete}}, and {{CamelHBaseScan}}. |
| {{maxResults}} | {{100}} | The maximum number of rows to scan.*Supported operations*: {{CamelHBaseScan}}. |
| {{mappingStrategyName}} | {{header}} | The strategy to use for mapping Camel messages to HBase columns. Supported values: {{header}}, or {{body}}. |
| {{mappingStrategyClassName}} | {{null}} | The class name of a custom mapping strategy implementation. |
| {{filters}} | {{null}} | A list of filters. *Supported operations*: {{CamelHBaseScan}}. |
{div}

Header mapping options:

Header mapping options:

Put Operations.

HBase is a column based store, which allows you to store data into a specific column of a specific row. Columns are grouped into families, so in order to specify a column you need to specify the column family and the qualifier of that column. To store data into a specific column you need to specify both the column and the row.

The simplest scenario for storing data into HBase from a camel route, would be to store part of the message body to specified HBase column.

        <route>
            <from uri="direct:in"/>
            <!-- Set the HBase Row -->
            <setHeader headerName="CamelHBaseRowId">
                <el>${in.body.id}</el>
            </setHeader>
            <!-- Set the HBase Value -->
            <setHeader headerName="CamelHBaseValue">
                <el>${in.body.value}</el>
            </setHeader>
            <to uri="hbase:mytable?opertaionoperation=CamelHBasePut&amp;family=myfamily&amp;qualifier=myqualifier"/>
        </route>

The route above assumes that the message body contains an object that has an id and value property and will store the content of value in the HBase column myfamily:myqualifier in the row specified by id. If we needed to specify more than one column/value pairs we could just specify additional column mappings:. Notice that you must use numbers from the 2nd header onwards, eg RowId2, RowId3, RowId4, etc. Only the 1st header does not have the number 1.

        <route>
            <from uri="direct:in"/>
            <!-- Set the HBase Row 1st column -->
            <setHeader headerName="CamelHBaseRowId">
                <el>${in.body.id}</el>
            </setHeader>
            <!-- Set the HBase Row 2nd column -->
            <setHeader headerName="CamelHBaseRowIdCamelHBaseRowId2">
                <el>${in.body.id}</el>
            </setHeader>
            <!-- Set the HBase Value for 1st column -->
            <setHeader headerName="CamelHBaseValue">
                <el>${in.body.value}</el>
            </setHeader>
            <!-- Set the HBase Value for 2nd column -->
            <setHeader headerName="CamelHBaseValue2">
                <el>${in.body.othervalue}</el>
            </setHeader>
            <to uri="hbase:mytable?opertaionoperation=CamelHBasePut&amp;family=myfamily&amp;qualifier=myqualifier&amp;family2=myfamily&amp;qualifier2=myqualifier2"/>
        </route>

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A Get Operation is an operation that is used to retrieve one or more values from a specified HBase row. To specify what are the values that you want to retrieve you can just specify them as part of the uri or as message headers.

        <route>
            <from uri="direct:in"/>
            <!-- Set the HBase Row of the Get -->
            <setHeader headerName="CamelHBaseRowId">
                <el>${in.body.id}</el>
            </setHeader>
            <to uri="hbase:mytable?opertaionoperation=CamelHBaseGet&amp;family=myfamily&amp;qualifier=myqualifier&amp;valueType=java.lang.Long"/>
            <to uri="log:out"/>
        </route>

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You can also you camel-hbase to perform HBase delete operation. The delete operation will remove an entire row. All that needs to be specified is one or more rows as part of the message headers.

        <route>
            <from uri="direct:in"/>
            <!-- Set the HBase Row of the Get -->
            <setHeader headerName="CamelHBaseRowId">
                <el>${in.body.id}</el>
            </setHeader>
            <to uri="hbase:mytable?opertaionoperation=CamelHBaseDelete"/>
        </route>

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A scan operation is the equivalent of a query in HBase. You can use the scan operation to retrieve multiple rows. To specify what columns should be part of the result and also specify how the values will be converted to objects you can use either uri options or headers.

        <route>
            <from uri="direct:in"/>
            <to uri="hbase:mytable?opertaionoperation=CamelHBaseScan&amp;family=myfamily&amp;qualifier=myqualifier&amp;valueType=java.lang.Long&amp;rowType=java.lang.String"/>
            <to uri="log:out"/>
        </route>

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For example to perform scan using as criteria the message headers, you can make use of the ModelAwareColumnMatchingFilter as shown below.

        <route>
            <from uri="direct:scan"/>
            <!-- Set the Criteria -->
            <setHeader headerName="CamelHBaseFamily">
                <constant>name</constant>
            </setHeader>
            <setHeader headerName="CamelHBaseQualifier">
                <constant>first</constant>
            </setHeader>
            <setHeader headerName="CamelHBaseValue">
                <el>in.body.firstName</el>
            </setHeader>
            <setHeader headerName="CamelHBaseFamily2">
                <constant>name</constant>
            </setHeader>
            <setHeader headerName="CamelHBaseQualifier2">
                <constant>last</constant>
            </setHeader>
            <setHeader headerName="CamelHBaseValue2">
                <el>in.body.lastName</el>
            </setHeader>
            <!-- Set additional fields that you want to be return by skipping value -->
            <setHeader headerName="CamelHBaseFamily3">
                <constant>address</constant>
            </setHeader>
            <setHeader headerName="CamelHBaseQualifier3">
                <constant>country</constant>
            </setHeader>
            <to uri="hbase:mytable?opertaionoperation=CamelHBaseScan&amp;filters=#myFilterList"/>
        </route>

        <bean id="myFilters" class="java.util.ArrayList">
            <constructor-arg>
                <list>
                    <bean class="org.apache.camel.component.hbase.filters.ModelAwareColumnMatchingFilter"/>
                </list>
            </constructor-arg>
        </bean>

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The Camel HBase Consumer, will perform repeated scan on the specified HBase table and will return the scan results as part of the message. You can either specify header mapping (default) or body mapping. The later latter will just add the org.apache.camel.component.hbase.model.HBaseData as part of the message body.

hbase://table[?options]

You can specify the columns that you want to be return and their types as part of the uri options:

hbase:mutable?family=name&qualifer=first&valueType=java.lang.String&family=address&qualifer=number&valueType2=java.lang.Integer&rowType=java.lang.Long

The example above will create a model object that is consisted of the specified fields and the scan results will populate the model object with values. Finally the mapping strategy will be used to map this model to the camel message.

Supported URI options on consumer

{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{initialDelay}} | {{1000}} | Milliseconds before the first polling starts. |
| {{delay}} | {{500}} | Milliseconds before the next poll. |
| {{useFixedDelay}} | {{true}} | Controls if fixed delay or fixed rate is used. See [ScheduledExecutorService|http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/ScheduledExecutorService.html] in JDK for details. |
| timeUnit | {{TimeUnit.MILLISECONDS}} | time unit for {{initialDelay}} and {{delay}} options. |
| {{runLoggingLevel}} | {{TRACE}} | *Camel 2.8:* The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that. |
| {{operation}} | {{CamelHBasePut}} | The HBase operation to perform. *Supported values*: {{CamelHBasePut}}, {{CamelHBaseGet}}, {{CamelHBaseDelete}}, and {{CamelHBaseScan}}. |
| {{maxResults}} | {{100}} | The maximum number of rows to scan. *Supported operations:* {{CamelHBaseScan}}. |
| {{mappingStrategyName}} | {{header}} | The strategy to use for mapping Camel messages to HBase columns. Supported values: {{header}}, or {{body}}. |
| {{mappingStrategyClassName}} | {{null}} | The class name of a custom mapping strategy implementation. |
| {{filters}} | {{null}} | A list of filters. *Supported operations*: {{CamelHBaseScan}} |
{div}

Header mapping options:

on consumer

Header mapping options:

If the role of the rowModel is not clear, it allows you to construct the HBaseRow modle programmatically instead of "describing" it with uri options (such as family, qualifier, type etc).

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The camel-hbase component also provides an idempotent repository which can be used when you want to make sure that each message is processed only once. The HBase idempotent repository is configured with a table, a column family and a column qualifier and will create to that table a row per message.

HBaseConfiguration configuration = HBaseConfiguration.create();
HBaseIdempotentRepository repository = new HBaseIdempotentRepository(configuration, tableName, family, qualifier);

from("direct:in")
  .idempotentConsumer(header("messageId"), repository)
  .to("log:out);

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The header mapping is the default mapping.
To put the value "myvalue" into HBase row "myrow" and column "myfamily:mycolum" the message should contain the following headers:

To put more values for different columns and / or different rows you can specify additional headers suffixed with the index of the headers, e.g:

In the case of retrieval operations such as get or scan you can also specify for each column the type that you want the data to be converted to. For exampe:

Please note that in order to avoid boilerplate headers that are considered constant for all messages, you can also specify them as part of the endpoint uri, as you will see below.

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In order to use the body mapping strategy you will have to specify the option mappingStrategy as part of the uri, for example:

hbase:mytable?mappingStrategy=body

To use the body mapping strategy the body needs to contain an instance of org.apache.camel.component.hbase.model.HBaseData. You can construct t

HBaseData data = new HBaseData();
HBaseRow row = new HBaseRow();
row.setId("myRowId");
HBaseCell cell = new HBaseCell();
cell.setFamily("myfamily");
cell.setQualifier("myqualifier");
cell.setValue("myValue");
row.getCells().add(cell);
data.addRows().add(row);

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