io.cloudevents.amqp.impl.ProtonAmqpBinaryMessageReader Maven / Gradle / Ivy
/*
* Copyright 2018-Present The CloudEvents Authors
*
* 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 io.cloudevents.amqp.impl;
import io.cloudevents.SpecVersion;
import io.cloudevents.core.data.BytesCloudEventData;
import io.cloudevents.core.message.impl.BaseGenericBinaryMessageReaderImpl;
import org.apache.qpid.proton.amqp.messaging.ApplicationProperties;
import java.util.Objects;
import java.util.function.BiConsumer;
/**
* An AMQP 1.0 message reader that can be read as a CloudEvent.
*
*
* This reader reads sections of an AMQP message to construct a CloudEvent representation by doing the following:
*
* - If the content-type property is set for an AMQP message, the value of the property
* is represented as a cloud event datacontenttype attribute.
*
- If the (mandatory) application-properties of the AMQP message contains attributes and/or extentions,
* this reader will represent each property/extension as a cloud event attribute.
*
*
*/
public final class ProtonAmqpBinaryMessageReader extends BaseGenericBinaryMessageReaderImpl {
private final String contentType;
private final ApplicationProperties applicationProperties;
/**
* Create an instance of an AMQP message reader.
*
* @param version The version of the cloud event message.
* @param applicationProperties The application properties of the AMQP message that contains
* the cloud event metadata (i.e attributes and extensions).
* The applicationProperties MUST not be {@code null}.
* @param contentType The content-type property of the AMQP message or {@code null} if the message content type is unknown.
* @param payload The message payload or {@code null} if the message does not contain any payload.
*
* @throws NullPointerException if the applicationPropereties is {@code null}.
*/
public ProtonAmqpBinaryMessageReader(final SpecVersion version, final ApplicationProperties applicationProperties,
final String contentType, final byte[] payload) {
super(version, payload != null && payload.length > 0 ? BytesCloudEventData.wrap(payload) : null);
this.contentType = contentType;
this.applicationProperties = Objects.requireNonNull(applicationProperties);
}
@Override
protected boolean isContentTypeHeader(final String key) {
return key.equals(AmqpConstants.PROPERTY_CONTENT_TYPE);
}
/**
* Tests whether the given attribute key is prefixed with cloudEvents:
*
* @param key The key to test for the presence of the prefix.
* @return True if the specified key starts with the prefix or
* false otherwise.
*/
@Override
protected boolean isCloudEventsHeader(final String key) {
final int prefixLength = AmqpConstants.CE_PREFIX.length();
return key.length() > prefixLength && key.startsWith(AmqpConstants.CE_PREFIX);
}
/**
* Gets the cloud event attribute key without the preceding prefix.
*
* @param key The key containing the AMQP specific prefix.
*
* @return The key without the prefix.
*/
@Override
protected String toCloudEventsKey(final String key) {
return key.substring(AmqpConstants.CE_PREFIX.length());
}
/**
* Visits the content-type message property and all application-properties of this message reader.
*
* This method only visits properties containing a name and value which are not {@code null}.
*
* @param fn A callback to consume this reader's application-properties
* and content-type property.
*/
@Override
protected void forEachHeader(final BiConsumer fn) {
if (contentType != null) {
// visit the content-type message property
fn.accept(AmqpConstants.PROPERTY_CONTENT_TYPE, contentType);
}
// visit application-properties
applicationProperties.getValue().forEach((k, v) -> {
if (k != null && v != null) {
fn.accept(k, v);
}
});
}
/**
* Gets the cloud event representation of the value.
*
* This method simply returns the string representation of the type of value passed as argument.
*
* @param value The value of a CloudEvent attribute or extension.
*
* @return The string representation of the specified value.
*/
@Override
protected String toCloudEventsValue(final Object value) {
return value.toString();
}
}