TransformerDefinition.java

/**
 * 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.camel.model.transformer;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlType;
import org.apache.camel.CamelContext;
import org.apache.camel.model.InputTypeDefinition;
import org.apache.camel.model.OutputTypeDefinition;
import org.apache.camel.spi.DataType;
import org.apache.camel.spi.Metadata;
import org.apache.camel.spi.Transformer;

/**
 * <p>Represents a {@link Transformer} which declaratively transforms message content
 * according to the input type declared by {@link InputTypeDefinition} and/or output type
 * declared by {@link OutputTypeDefinition}.</p>
 * <p>If you specify from='java:com.example.ABC' and to='xml:XYZ', the transformer
 * will be picked up when current message type is 'java:com.example.ABC' and expected
 * message type is 'xml:XYZ'.
 * If you specify from='java' to='xml', then it will be picked up for all of java
 * to xml transformation.
 * Also it's possible to specify scheme='xml' so that the transformer will be picked up
 * for all of java to xml and xml to java transformation.</p>
 * 
 * {@see Transformer}
 * {@see InputTypeDefinition}
 * {@see OutputTypeDefinition}
 */
@Metadata(label = "transformation")
@XmlType(name = "transformer")
@XmlAccessorType(XmlAccessType.FIELD)
public abstract class TransformerDefinition {

    @XmlAttribute
    private String scheme;
    @XmlAttribute
    private String fromType;
    @XmlAttribute
    private String toType;

    public Transformer createTransformer(CamelContext context) throws Exception {
        return doCreateTransformer(context);
    };

    protected abstract Transformer doCreateTransformer(CamelContext context) throws Exception;

    public String getScheme() {
        return scheme;
    }

    /**
     * Set a scheme name supported by the transformer.
     * If you specify 'csv', the transformer will be picked up for all of 'csv' from/to
     * Java transformation. Note that the scheme matching is performed only when
     * no exactly matched transformer exists.
     *
     * @param scheme scheme name
     */
    public void setScheme(String scheme) {
        this.scheme = scheme;
    }

    public String getFromType() {
        return fromType;
    }

    /**
     * Set the 'from' data type name.
     * If you specify 'xml:XYZ', the transformer will be picked up if source type is
     * 'xml:XYZ'. If you specify just 'xml', the transformer matches with all of
     * 'xml' source type like 'xml:ABC' or 'xml:DEF'.
     * 
     * @param from 'from' data type name
     */
    public void setFromType(String from) {
        this.fromType = from;
    }

    /**
     * Set the 'from' data type using Java class.
     *
     * @param clazz 'from' Java class
     */
    public void setFromType(Class<?> clazz) {
        this.fromType = new DataType(clazz).toString();
    }

    public String getToType() {
        return toType;
    }

    /**
     * Set the 'to' data type name.
     * If you specify 'json:XYZ', the transformer will be picked up if destination type is
     * 'json:XYZ'. If you specify just 'json', the transformer matches with all of
     * 'json' destination type like 'json:ABC' or 'json:DEF'.
     *
     * @param to 'to' data type name
     */
    public void setToType(String to) {
        this.toType = to;
    }

    /**
     * Set the 'to' data type using Java class.
     *
     * @param clazz 'to' Java class
     */
    public void setToType(Class<?> clazz) {
        this.toType = new DataType(clazz).toString();
    }

}