1 files changed, 69 insertions, 0 deletions
diff --git a/common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/transformer/ThreadLocalTransformer.java b/common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/transformer/ThreadLocalTransformer.java
new file mode 100644
index 0000000000..9280301faf
--- /dev/null
+++ b/common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/transformer/ThreadLocalTransformer.java
@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * Copyright (c) 2008, 2013 Oracle. All rights reserved.
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0, which accompanies this distribution
+ * and is available at http://www.eclipse.org/legal/epl-v10.html.
+ * 
+ * Contributors:
+ *     Oracle - initial API and implementation
+ ******************************************************************************/
+package org.eclipse.jpt.common.utility.internal.transformer;
+
+import org.eclipse.jpt.common.utility.transformer.Transformer;
+
+/**
+ * This transformer allows the client to specify a different transformer for each
+ * thread. If there is no transformer for the current thread, the configured default
+ * transformer is used.
+ * 
+ * @param <I> input: the type of the object passed to the transformer
+ * @param <O> output: the type of the object returned by the transformer
+ * 
+ * @see #set(Transformer)
+ */
+public class ThreadLocalTransformer<I, O>
+	implements Transformer<I, O>
+{
+	private final ThreadLocal<Transformer<? super I, ? extends O>> threadLocal;
+	private final Transformer<? super I, ? extends O> defaultTransformer;
+
+	public ThreadLocalTransformer(Transformer<? super I, ? extends O> defaultTransformer) {
+		super();
+		if (defaultTransformer == null) {
+			throw new NullPointerException();
+		}
+		this.defaultTransformer = defaultTransformer;
+		this.threadLocal = this.buildThreadLocal();
+	}
+
+	private ThreadLocal<Transformer<? super I, ? extends O>> buildThreadLocal() {
+		return new ThreadLocal<Transformer<? super I, ? extends O>>();
+	}
+
+	public O transform(I input) {
+		return this.get().transform(input);
+	}
+
+	private Transformer<? super I, ? extends O> get() {
+		Transformer<? super I, ? extends O> transformer = this.threadLocal.get();
+		if (transformer != null) {
+			return transformer;
+		}
+		return this.defaultTransformer;
+	}
+
+	/**
+	 * Set the current thread's transformer to the specified value.
+	 */
+	public void set(Transformer<? super I, ? extends O> transformer) {
+		this.threadLocal.set(transformer);
+	}
+
+	/**
+	 * Return the string representation of the current thread's transformer.
+	 */
+	@Override
+	public String toString() {
+		return this.get().toString();
+	}
+}