Introduce the foundations of the new endpoint infrastructure

Author: wilkinsona

spring-boot/src/main/java/org/springframework/boot/endpoint/AnnotationEndpointDiscoverer.java

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+/*
+ * Copyright 2012-2017 the original author or 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 org.springframework.boot.endpoint;
+
+/**
+ * Provide the caching configuration of an endpoint.
+ *
+ * @author Stephane Nicoll
+ * @since 2.0.0
+ */
+public class CachingConfiguration {
+
+	private final long timeToLive;
+
+	/**
+	 * Create a new instance with the caching period to use.
+	 * @param timeToLive the time to live of an operation result in milliseconds
+	 */
+	public CachingConfiguration(long timeToLive) {
+		this.timeToLive = timeToLive;
+	}
+
+	/**
+	 * Return the operation caching period in milliseconds.
+	 * @return the time to live of an operation result
+	 */
+	public long getTimeToLive() {
+		return this.timeToLive;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/endpoint/CachingConfiguration.java

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+/*
+ * Copyright 2012-2017 the original author or 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 org.springframework.boot.endpoint;
+
+import java.util.Map;
+
+import org.springframework.util.Assert;
+
+/**
+ * An {@link OperationInvoker} that caches the response of an operation with a
+ * configurable time to live.
+ *
+ * @author Stephane Nicoll
+ * @since 2.0.0
+ */
+public class CachingOperationInvoker implements OperationInvoker {
+
+	private final OperationInvoker target;
+
+	private final long timeToLive;
+
+	private volatile CachedResponse cachedResponse;
+
+	/**
+	 * Create a new instance with the target {@link OperationInvoker} to use to compute
+	 * the response and the time to live for the cache.
+	 * @param target the {@link OperationInvoker} this instance wraps
+	 * @param timeToLive the maximum time in milliseconds that a response can be cached
+	 */
+	public CachingOperationInvoker(OperationInvoker target, long timeToLive) {
+		Assert.state(timeToLive > 0, "TimeToLive must be strictly positive");
+		this.target = target;
+		this.timeToLive = timeToLive;
+	}
+
+	/**
+	 * Return the maximum time in milliseconds that a response can be cached.
+	 * @return the time to live of a response
+	 */
+	public long getTimeToLive() {
+		return this.timeToLive;
+	}
+
+	@Override
+	public Object invoke(Map<String, Object> arguments) {
+		long accessTime = System.currentTimeMillis();
+		CachedResponse cached = this.cachedResponse;
+		if (cached == null || cached.isStale(accessTime, this.timeToLive)) {
+			Object response = this.target.invoke(arguments);
+			this.cachedResponse = new CachedResponse(response, accessTime);
+			return response;
+		}
+		return cached.getResponse();
+	}
+
+	/**
+	 * A cached response that encapsulates the response itself and the time at which it
+	 * was created.
+	 */
+	static class CachedResponse {
+
+		private final Object response;
+
+		private final long creationTime;
+
+		CachedResponse(Object response, long creationTime) {
+			this.response = response;
+			this.creationTime = creationTime;
+		}
+
+		public boolean isStale(long accessTime, long timeToLive) {
+			return (accessTime - this.creationTime) >= timeToLive;
+		}
+
+		public Object getResponse() {
+			return this.response;
+		}
+
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/endpoint/CachingOperationInvoker.java

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+/*
+ * Copyright 2012-2017 the original author or 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 org.springframework.boot.endpoint;
+
+import org.springframework.boot.context.properties.bind.convert.BinderConversionService;
+import org.springframework.core.convert.ConversionService;
+
+/**
+ * {@link OperationParameterMapper} that uses a {@link ConversionService} to convert a
+ * parameter value if necessary.
+ *
+ * @author Stephane Nicoll
+ * @since 2.0.0
+ */
+public class ConversionServiceOperationParameterMapper
+		implements OperationParameterMapper {
+
+	private final ConversionService conversionService;
+
+	/**
+	 * Create a new instance with the {@link ConversionService} to use.
+	 * @param conversionService the conversion service
+	 */
+	public ConversionServiceOperationParameterMapper(
+			ConversionService conversionService) {
+		this.conversionService = new BinderConversionService(conversionService);
+	}
+
+	@Override
+	public <T> T mapParameter(Object input, Class<T> parameterType) {
+		if (input == null || parameterType.isAssignableFrom(input.getClass())) {
+			return parameterType.cast(input);
+		}
+		try {
+			return this.conversionService.convert(input, parameterType);
+		}
+		catch (Exception ex) {
+			throw new ParameterMappingException(input, parameterType, ex);
+		}
+	}
+
+	protected final ConversionService getConversionService() {
+		return this.conversionService;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/endpoint/ConversionServiceOperationParameterMapper.java

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+/*
+ * Copyright 2012-2017 the original author or 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 org.springframework.boot.endpoint;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Identifies a type as being an endpoint.
+ *
+ * @author Andy Wilkinson
+ * @since 2.0.0
+ * @see EndpointDiscoverer
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface Endpoint {
+
+	/**
+	 * The id of the endpoint.
+	 * @return the id
+	 */
+	String id();
+
+	/**
+	 * Defines the endpoint {@link EndpointType types} that should be exposed. By default,
+	 * all types are exposed.
+	 * @return the endpoint types to expose
+	 */
+	EndpointType[] types() default {};
+
+	/**
+	 * Whether or not the endpoint is enabled by default.
+	 * @return {@code true} if the endpoint is enabled by default, otherwise {@code false}
+	 */
+	boolean enabledByDefault() default true;
+
+}

spring-boot/src/main/java/org/springframework/boot/endpoint/Endpoint.java

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+/*
+ * Copyright 2012-2017 the original author or 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 org.springframework.boot.endpoint;
+
+import java.util.Collection;
+
+/**
+ * Discovers endpoints and provides a {@link EndpointInfo} for each of them.
+ *
+ * @param <T> the type of the operation
+ * @author Andy Wilkinson
+ * @author Stephane Nicoll
+ * @since 2.0.0
+ */
+public interface EndpointDiscoverer<T extends EndpointOperation> {
+
+	/**
+	 * Perform endpoint discovery.
+	 * @return the discovered endpoints
+	 */
+	Collection<EndpointInfo<T>> discoverEndpoints();
+
+}

spring-boot/src/main/java/org/springframework/boot/endpoint/EndpointDiscoverer.java

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+/*
+ * Copyright 2012-2017 the original author or 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 org.springframework.boot.endpoint;
+
+import java.util.Collection;
+
+/**
+ * Information describing an endpoint.
+ *
+ * @param <T> the type of the endpoint operation info
+ * @author Andy Wilkinson
+ * @since 2.0.0
+ */
+public class EndpointInfo<T extends EndpointOperation> {
+
+	private final String id;
+
+	private final boolean enabledByDefault;
+
+	private final Collection<T> operations;
+
+	/**
+	 * Creates a new {@code EndpointInfo} describing an endpoint with the given {@code id}
+	 * and {@code operations}.
+	 * @param id the id of the endpoint
+	 * @param enabledByDefault whether or not the endpoint is enabled by default
+	 * @param operations the operations of the endpoint
+	 */
+	public EndpointInfo(String id, boolean enabledByDefault, Collection<T> operations) {
+		this.id = id;
+		this.enabledByDefault = enabledByDefault;
+		this.operations = operations;
+	}
+
+	/**
+	 * Returns the id of the endpoint.
+	 * @return the id
+	 */
+	public String getId() {
+		return this.id;
+	}
+
+	/**
+	 * Returns whether or not this endpoint is enabled by default.
+	 * @return {@code true} if it is enabled by default, otherwise {@code false}
+	 */
+	public boolean isEnabledByDefault() {
+		return this.enabledByDefault;
+	}
+
+	/**
+	 * Returns the operations of the endpoint.
+	 * @return the operations
+	 */
+	public Collection<T> getOperations() {
+		return this.operations;
+	}
+
+}