From 15f0e40e3893b4ac5208385cd1250a7a236ab7a1 Mon Sep 17 00:00:00 2001
From: Keith Donald <kdonald@vmware.com>
Date: Sat, 12 Jul 2008 23:16:30 +0000
Subject: [PATCH] Flow resource loader fix for classpath resources

---
 .../model/FlowRelativeResourceLoader.java     | 60 +++++++++++++++++++
 .../builder/model/SubflowExpression.java      | 49 +++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/FlowRelativeResourceLoader.java
 create mode 100644 spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/SubflowExpression.java

diff --git a/spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/FlowRelativeResourceLoader.java b/spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/FlowRelativeResourceLoader.java
new file mode 100644
index 00000000..9714a344
--- /dev/null
+++ b/spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/FlowRelativeResourceLoader.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2004-2007 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.webflow.engine.builder.model;
+
+import java.io.IOException;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
+
+/**
+ * A resource loader that loads other resources relative to a Flow definition resource. Allows for easy loading of
+ * flow-relative resources using the standard {@link ResourceLoader} interface.
+ * 
+ * @author Keith Donald
+ */
+class FlowRelativeResourceLoader implements ResourceLoader {
+
+	private Resource flowResource;
+
+	public FlowRelativeResourceLoader(Resource resource) {
+		this.flowResource = resource;
+	}
+
+	public ClassLoader getClassLoader() {
+		return flowResource.getClass().getClassLoader();
+	}
+
+	public Resource getResource(String location) {
+		if (location.startsWith(CLASSPATH_URL_PREFIX)) {
+			return new ClassPathResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());
+		} else {
+			return createFlowRelativeResource(location);
+		}
+	}
+
+	private Resource createFlowRelativeResource(String location) {
+		try {
+			return flowResource.createRelative(location);
+		} catch (IOException e) {
+			IllegalArgumentException iae = new IllegalArgumentException(
+					"Unable to access a flow relative resource at location '" + location + "'");
+			iae.initCause(e);
+			throw iae;
+		}
+	}
+}
\ No newline at end of file
diff --git a/spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/SubflowExpression.java b/spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/SubflowExpression.java
new file mode 100644
index 00000000..a0d1d2ac
--- /dev/null
+++ b/spring-webflow/src/main/java/org/springframework/webflow/engine/builder/model/SubflowExpression.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2004-2007 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.webflow.engine.builder.model;
+
+import org.springframework.binding.expression.EvaluationException;
+import org.springframework.binding.expression.Expression;
+import org.springframework.webflow.definition.registry.FlowDefinitionLocator;
+
+class SubflowExpression implements Expression {
+
+	private Expression subflowId;
+
+	private FlowDefinitionLocator flowDefinitionLocator;
+
+	public SubflowExpression(Expression subflowId, FlowDefinitionLocator flowDefinitionLocator) {
+		this.subflowId = subflowId;
+		this.flowDefinitionLocator = flowDefinitionLocator;
+	}
+
+	public Object getValue(Object context) throws EvaluationException {
+		String subflowId = (String) this.subflowId.getValue(context);
+		return flowDefinitionLocator.getFlowDefinition(subflowId);
+	}
+
+	public void setValue(Object context, Object value) throws EvaluationException {
+		throw new UnsupportedOperationException("Cannot set a subflow expression");
+	}
+
+	public Class getValueType(Object context) {
+		return null;
+	}
+
+	public String getExpressionString() {
+		return null;
+	}
+}
\ No newline at end of file