org.ldp4j.application.session.SnapshotResolver Maven / Gradle / Ivy
/**
* #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
* This file is part of the LDP4j Project:
* http://www.ldp4j.org/
*
* Center for Open Middleware
* http://www.centeropenmiddleware.com/
* #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
* Copyright (C) 2014-2016 Center for Open Middleware.
* #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
* 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.
* #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
* Artifact : org.ldp4j.framework:ldp4j-application-api:0.2.1
* Bundle : ldp4j-application-api-0.2.1.jar
* #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
*/
package org.ldp4j.application.session;
import java.net.URI;
import java.util.Objects;
import org.ldp4j.application.spi.ResourceSnapshotResolver;
import org.ldp4j.application.spi.RuntimeDelegate;
/**
* Utility class for resolving the endpoints (URI) where the resources managed
* by the LDP4j framework are published, and for discovering which resources are
* addressed by a given URI.
*/
public final class SnapshotResolver {
/**
* Builder class for creating {@code SnapshotResolver} instances.
*/
public static final class Builder {
private ReadSession session;
private URI canonicalBase;
private Builder() {
}
/**
* Define the canonical base URI to be used for the resolution of
* endpoints.
*
* @param base
* the canonical base URI.
* @return this builder.
*/
public Builder withCanonicalBase(URI base) {
this.canonicalBase = base;
return this;
}
/**
* Define the session to be used for the resolution of resource
* snapshots.
*
* @param session
* the session
* @return this builder.
*/
public Builder withReadSession(ReadSession session) {
this.session = session;
return this;
}
/**
* Return a configured snapshot resolver instance.
*
* @return a configured snapshot resolver instance
* @throws NullPointerException
* if the canonical base URI or the session are null.
* @throws IllegalArgumentException
* if the canonical base URI is not hierarchical and
* absolute.
*/
public SnapshotResolver build() {
return
new SnapshotResolver(
RuntimeDelegate.
getInstance().
createResourceResolver(
getCanonicalBase(),
Objects.requireNonNull(this.session,"Session cannot be null")));
}
private URI getCanonicalBase() {
Objects.requireNonNull(this.canonicalBase,"Canonical base cannot be null");
if(this.canonicalBase.isOpaque()) {
throw new IllegalArgumentException("Canonical base '"+this.canonicalBase+"' is not hierarchical");
}
if(!this.canonicalBase.isAbsolute()) {
throw new IllegalArgumentException("Canonical base '"+this.canonicalBase+"' is not absolute");
}
return this.canonicalBase;
}
}
private final ResourceSnapshotResolver resolver;
private SnapshotResolver(ResourceSnapshotResolver resolver) {
this.resolver = resolver;
}
/**
* Return the URI used to publish a resource.
*
* @param snapshot
* the snapshot of the resource that is to be resolved.
* @throws SnapshotResolutionException
* if the snapshot cannot be resolved to a URI.
* @return the URI used to published the resource that represents the
* snapshot.
*/
public URI toURI(ResourceSnapshot snapshot) {
return this.resolver.resolve(snapshot);
}
/**
* Return a snapshot of the resource published at a given URI.
*
* @param endpoint
* the URI that is to be resolved.
* @throws SnapshotResolutionException
* if the URI cannot be resolved to a resource snapshot.
* @return a snapshot of the resource that is published at the specified
* endpoint.
*/
public ResourceSnapshot fromURI(URI endpoint) {
return this.resolver.resolve(endpoint);
}
/**
* Create a {@code Builder} instance.
* @return a {@code Builder} instance.
*/
public static Builder builder() {
return new Builder();
}
}