1 files changed, 273 insertions, 0 deletions
diff --git a/src/java/org/apache/fop/apps/io/ResourceResolverFactory.java b/src/java/org/apache/fop/apps/io/ResourceResolverFactory.java
new file mode 100644
index 000000000..881db20f7
--- /dev/null
+++ b/src/java/org/apache/fop/apps/io/ResourceResolverFactory.java
@@ -0,0 +1,273 @@
+/*
+ * 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;
+
+/**
+ * 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-schema aware resource resolver. Temporary resource URIs are
+     * created by {@link TempResourceURIGenerator}.
+     *
+     * @param tempResourceResolver the temporary-resource-schema 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);
+    }
+
+    public static SchemaAwareResourceResolverBuilder createSchemaAwareResourceResolverBuilder(
+            ResourceResolver defaultResolver) {
+        return new SchemaAwareResourceResolverBuilderImpl(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());
+        }
+
+        public Resource getResource(URI uri) throws IOException {
+            return delegate.getResource(uri);
+        }
+
+        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);
+        }
+
+        public Resource getResource(URI uri) throws IOException {
+            if (isTempUri(uri)) {
+                return tempResourceResolver.getResource(uri.getPath());
+            } else {
+                return defaultResourceResolver.getResource(uri);
+            }
+        }
+
+        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;
+        }
+
+        public Resource getResource(String id) throws IOException {
+            return new Resource(getTempFile(id).toURI().toURL().openStream());
+        }
+
+        public OutputStream getOutputStream(String id) throws IOException {
+            File file = getTempFile(id);
+            file.createNewFile();
+            return new FileOutputStream(file);
+        }
+    }
+
+    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 SchemaAwareResourceResolver implements ResourceResolver {
+
+        private final Map<String, ResourceResolver> schemaHandlingResourceResolvers;
+
+        private final ResourceResolver defaultResolver;
+
+        private SchemaAwareResourceResolver(
+                Map<String, ResourceResolver> schemaHandlingResourceResolvers,
+                ResourceResolver defaultResolver) {
+            this.schemaHandlingResourceResolvers = schemaHandlingResourceResolvers;
+            this.defaultResolver = defaultResolver;
+        }
+
+        private ResourceResolver getResourceResolverForSchema(URI uri) {
+            String schema = uri.getScheme();
+            if (schemaHandlingResourceResolvers.containsKey(schema)) {
+                return schemaHandlingResourceResolvers.get(schema);
+            } else {
+                return defaultResolver;
+            }
+        }
+
+        public Resource getResource(URI uri) throws IOException {
+            return getResourceResolverForSchema(uri).getResource(uri);
+        }
+
+        public OutputStream getOutputStream(URI uri) throws IOException {
+            return getResourceResolverForSchema(uri).getOutputStream(uri);
+        }
+    }
+
+    public interface SchemaAwareResourceResolverBuilder {
+
+        void registerResourceResolverForSchema(String schema, ResourceResolver resourceResolver);
+
+        ResourceResolver build();
+    }
+
+    private static final class CompletedSchemaAwareResourceResolverBuilder
+            implements SchemaAwareResourceResolverBuilder {
+
+        private static final SchemaAwareResourceResolverBuilder INSTANCE
+                = new CompletedSchemaAwareResourceResolverBuilder();
+
+        public ResourceResolver build() {
+            throw new IllegalStateException("Resource resolver already built");
+        }
+
+        public void registerResourceResolverForSchema(String schema,
+                ResourceResolver resourceResolver) {
+            throw new IllegalStateException("Resource resolver already built");
+        }
+    }
+
+    private static final class ActiveSchemaAwareResourceResolverBuilder
+            implements SchemaAwareResourceResolverBuilder {
+
+        private final Map<String, ResourceResolver> schemaHandlingResourceResolvers
+                = new HashMap<String, ResourceResolver>();
+
+        private final ResourceResolver defaultResolver;
+
+        private ActiveSchemaAwareResourceResolverBuilder(ResourceResolver defaultResolver) {
+            this.defaultResolver = defaultResolver;
+        }
+
+        public void registerResourceResolverForSchema(String schema,
+                ResourceResolver resourceResolver) {
+            schemaHandlingResourceResolvers.put(schema, resourceResolver);
+        }
+
+        public ResourceResolver build() {
+            return new SchemaAwareResourceResolver(
+                    Collections.unmodifiableMap(schemaHandlingResourceResolvers), defaultResolver);
+        }
+
+    }
+
+    private static final class SchemaAwareResourceResolverBuilderImpl
+            implements SchemaAwareResourceResolverBuilder {
+
+        private SchemaAwareResourceResolverBuilder delegate;
+
+        private SchemaAwareResourceResolverBuilderImpl(ResourceResolver defaultResolver) {
+            this.delegate = new ActiveSchemaAwareResourceResolverBuilder(defaultResolver);
+        }
+
+        public void registerResourceResolverForSchema(String schema,
+                ResourceResolver resourceResolver) {
+            delegate.registerResourceResolverForSchema(schema, resourceResolver);
+        }
+
+        public ResourceResolver build() {
+            ResourceResolver resourceResolver = delegate.build();
+            delegate = CompletedSchemaAwareResourceResolverBuilder.INSTANCE;
+            return resourceResolver;
+        }
+    }
+
+}