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- /*
- * 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.
- */
-
- /* $Id$ */
-
- package org.apache.fop.apps.io;
-
- import java.io.File;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.OutputStream;
- import java.net.URI;
- import java.util.Collections;
- import java.util.HashMap;
- import java.util.Map;
-
- import org.apache.xmlgraphics.io.Resource;
- import org.apache.xmlgraphics.io.ResourceResolver;
- import org.apache.xmlgraphics.io.TempResourceResolver;
- import org.apache.xmlgraphics.io.TempResourceURIGenerator;
-
- /**
- * A factory class for {@link ResourceResolver}s.
- */
- public final class ResourceResolverFactory {
-
- private ResourceResolverFactory() {
- }
-
- /**
- * Returns the default resource resolver, this is most basic resolver which can be used when
- * no there are no I/O or file access restrictions.
- *
- * @return the default resource resolver
- */
- public static ResourceResolver createDefaultResourceResolver() {
- return DefaultResourceResolver.INSTANCE;
- }
-
- /**
- * A helper merthod that creates an internal resource resolver using the default resover:
- * {@link ResourceResolverFactory#createDefaultResourceResolver()}.
- *
- * @param baseURI the base URI from which to resolve URIs
- * @return the default internal resource resolver
- */
- public static InternalResourceResolver createDefaultInternalResourceResolver(URI baseURI) {
- return new InternalResourceResolver(baseURI, createDefaultResourceResolver());
- }
-
- /**
- * Creates an interal resource resolver given a base URI and a resource resolver.
- *
- * @param baseURI the base URI from which to resolve URIs
- * @param resolver the resource resolver
- * @return the internal resource resolver
- */
- public static InternalResourceResolver createInternalResourceResolver(URI baseURI,
- ResourceResolver resolver) {
- return new InternalResourceResolver(baseURI, resolver);
- }
-
- /**
- * Creates a temporary-resource-scheme aware resource resolver. Temporary resource URIs are
- * created by {@link TempResourceURIGenerator}.
- *
- * @param tempResourceResolver the temporary-resource-scheme resolver to use
- * @param defaultResourceResolver the default resource resolver to use
- * @return the ressource resolver
- */
- public static ResourceResolver createTempAwareResourceResolver(
- TempResourceResolver tempResourceResolver,
- ResourceResolver defaultResourceResolver) {
- return new TempAwareResourceResolver(tempResourceResolver, defaultResourceResolver);
- }
-
- /**
- * This creates the builder class for binding URI schemes to implementations of
- * {@link ResourceResolver}. This allows users to define their own URI schemes such that they
- * have finer control over the acquisition of resources.
- *
- * @param defaultResolver the default resource resolver that should be used in the event that
- * none of the other registered resolvers match the scheme
- * @return the scheme aware {@link ResourceResolver} builder
- */
- public static SchemeAwareResourceResolverBuilder createSchemeAwareResourceResolverBuilder(
- ResourceResolver defaultResolver) {
- return new SchemeAwareResourceResolverBuilderImpl(defaultResolver);
- }
-
- private static final class DefaultResourceResolver implements ResourceResolver {
-
- private static final ResourceResolver INSTANCE = new DefaultResourceResolver();
-
- private final TempAwareResourceResolver delegate;
-
- private DefaultResourceResolver() {
- delegate = new TempAwareResourceResolver(new DefaultTempResourceResolver(),
- new NormalResourceResolver());
- }
-
- /** {@inheritDoc} */
- public Resource getResource(URI uri) throws IOException {
- return delegate.getResource(uri);
- }
-
- /** {@inheritDoc} */
- public OutputStream getOutputStream(URI uri) throws IOException {
- return delegate.getOutputStream(uri);
- }
-
- }
-
- private static final class TempAwareResourceResolver implements ResourceResolver {
-
- private final TempResourceResolver tempResourceResolver;
-
- private final ResourceResolver defaultResourceResolver;
-
- public TempAwareResourceResolver(TempResourceResolver tempResourceHandler,
- ResourceResolver defaultResourceResolver) {
- this.tempResourceResolver = tempResourceHandler;
- this.defaultResourceResolver = defaultResourceResolver;
- }
-
- private static boolean isTempURI(URI uri) {
- return TempResourceURIGenerator.isTempURI(uri);
- }
-
- /** {@inheritDoc} */
- public Resource getResource(URI uri) throws IOException {
- if (isTempURI(uri)) {
- return tempResourceResolver.getResource(uri.getPath());
- } else {
- return defaultResourceResolver.getResource(uri);
- }
- }
-
- /** {@inheritDoc} */
- public OutputStream getOutputStream(URI uri) throws IOException {
- if (isTempURI(uri)) {
- return tempResourceResolver.getOutputStream(uri.getPath());
- } else {
- return defaultResourceResolver.getOutputStream(uri);
- }
- }
- }
-
- private static class DefaultTempResourceResolver implements TempResourceResolver {
- private static File getTempFile(String path) throws IOException {
- File file = new File(System.getProperty("java.io.tmpdir"), path);
- file.deleteOnExit();
- return file;
- }
-
- /** {@inheritDoc} */
- public Resource getResource(String id) throws IOException {
- return new Resource(getTempFile(id).toURI().toURL().openStream());
- }
-
- /** {@inheritDoc} */
- public OutputStream getOutputStream(String id) throws IOException {
- File file = getTempFile(id);
- if (file.createNewFile()) {
- return new FileOutputStream(file);
- } else {
- throw new IOException("Filed to create temporary file: " + id);
- }
- }
- }
-
- private static class NormalResourceResolver implements ResourceResolver {
- public Resource getResource(URI uri) throws IOException {
- return new Resource(uri.toURL().openStream());
- }
-
- public OutputStream getOutputStream(URI uri) throws IOException {
- return new FileOutputStream(new File(uri));
- }
- }
-
- private static final class SchemeAwareResourceResolver implements ResourceResolver {
-
- private final Map<String, ResourceResolver> schemeHandlingResourceResolvers;
-
- private final ResourceResolver defaultResolver;
-
- private SchemeAwareResourceResolver(
- Map<String, ResourceResolver> schemEHandlingResourceResolvers,
- ResourceResolver defaultResolver) {
- this.schemeHandlingResourceResolvers = schemEHandlingResourceResolvers;
- this.defaultResolver = defaultResolver;
- }
-
- private ResourceResolver getResourceResolverForScheme(URI uri) {
- String scheme = uri.getScheme();
- if (schemeHandlingResourceResolvers.containsKey(scheme)) {
- return schemeHandlingResourceResolvers.get(scheme);
- } else {
- return defaultResolver;
- }
- }
-
- /** {@inheritDoc} */
- public Resource getResource(URI uri) throws IOException {
- return getResourceResolverForScheme(uri).getResource(uri);
- }
-
- /** {@inheritDoc} */
- public OutputStream getOutputStream(URI uri) throws IOException {
- return getResourceResolverForScheme(uri).getOutputStream(uri);
- }
- }
-
- /**
- * Implementations of this interface will be builders for {@link ResourceResolver}, they bind
- * URI schemes to their respective resolver. This gives users more control over the mechanisms
- * by which URIs are resolved.
- * <p>
- * Here is an example of how this could be used:
- * </p>
- * <p><code>
- * SchemeAwareResourceResolverBuilder builder
- * = ResourceResolverFactory.createSchemeAwareResourceResolverBuilder(defaultResolver);
- * builder.registerResourceResolverForScheme("test", testResolver);
- * builder.registerResourceResolverForScheme("anotherTest", test2Resolver);
- * ResourceResolver resolver = builder.build();
- * </code></p>
- * This will result in all URIs for the form "test:///..." will be resolved using the
- * <code>testResolver</code> object; URIs of the form "anotherTest:///..." will be resolved
- * using <code>test2Resolver</code>; all other URIs will be resolved from the defaultResolver.
- */
- public interface SchemeAwareResourceResolverBuilder {
-
- /**
- * Register a scheme with its respective {@link ResourceResolver}. This resolver will be
- * used as the only resolver for the specified scheme.
- *
- * @param scheme the scheme to be used with the given resolver
- * @param resourceResolver the resource resolver
- */
- void registerResourceResolverForScheme(String scheme, ResourceResolver resourceResolver);
-
- /**
- * Builds a {@link ResourceResolver} that will delegate to the respective resource resolver
- * when a registered URI scheme is given
- *
- * @return a resolver that delegates to the appropriate scheme resolver
- */
- ResourceResolver build();
- }
-
- private static final class CompletedSchemeAwareResourceResolverBuilder
- implements SchemeAwareResourceResolverBuilder {
-
- private static final SchemeAwareResourceResolverBuilder INSTANCE
- = new CompletedSchemeAwareResourceResolverBuilder();
-
- /** {@inheritDoc} */
- public ResourceResolver build() {
- throw new IllegalStateException("Resource resolver already built");
- }
-
- /** {@inheritDoc} */
- public void registerResourceResolverForScheme(String scheme,
- ResourceResolver resourceResolver) {
- throw new IllegalStateException("Resource resolver already built");
- }
- }
-
- private static final class ActiveSchemeAwareResourceResolverBuilder
- implements SchemeAwareResourceResolverBuilder {
-
- private final Map<String, ResourceResolver> schemeHandlingResourceResolvers
- = new HashMap<String, ResourceResolver>();
-
- private final ResourceResolver defaultResolver;
-
- private ActiveSchemeAwareResourceResolverBuilder(ResourceResolver defaultResolver) {
- this.defaultResolver = defaultResolver;
- }
-
- /** {@inheritDoc} */
- public void registerResourceResolverForScheme(String scheme,
- ResourceResolver resourceResolver) {
- schemeHandlingResourceResolvers.put(scheme, resourceResolver);
- }
-
- /** {@inheritDoc} */
- public ResourceResolver build() {
- return new SchemeAwareResourceResolver(
- Collections.unmodifiableMap(schemeHandlingResourceResolvers), defaultResolver);
- }
-
- }
-
- private static final class SchemeAwareResourceResolverBuilderImpl
- implements SchemeAwareResourceResolverBuilder {
-
- private SchemeAwareResourceResolverBuilder delegate;
-
- private SchemeAwareResourceResolverBuilderImpl(ResourceResolver defaultResolver) {
- this.delegate = new ActiveSchemeAwareResourceResolverBuilder(defaultResolver);
- }
-
- /** {@inheritDoc} */
- public void registerResourceResolverForScheme(String scheme,
- ResourceResolver resourceResolver) {
- delegate.registerResourceResolverForScheme(scheme, resourceResolver);
- }
-
- /** {@inheritDoc} */
- public ResourceResolver build() {
- ResourceResolver resourceResolver = delegate.build();
- delegate = CompletedSchemeAwareResourceResolverBuilder.INSTANCE;
- return resourceResolver;
- }
- }
- }
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