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[utils] / support / general / src / main / java / org / wamblee / xml / XslTransformer.java

diff --git a/support/general/src/main/java/org/wamblee/xml/XslTransformer.java b/support/general/src/main/java/org/wamblee/xml/XslTransformer.java
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+/*
+ * Copyright 2005 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.wamblee.xml;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerConfigurationException;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.URIResolver;
+import javax.xml.transform.dom.DOMResult;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+import javax.xml.transform.stream.StreamSource;
+
+import org.w3c.dom.Document;
+import org.wamblee.io.FileResource;
+
+/**
+ * XSL transformer for simplified usage of XSL transformations.
+ *
+ * @author Erik Brakkee
+ */
+public class XslTransformer {
+
+    private TransformerFactory _factory;
+
+    /**
+     * Constructs the URL resolver.
+     * 
+     * @param aResolver
+     *            URI resolver to use.
+     */
+    public XslTransformer(URIResolver aResolver) {
+        _factory = TransformerFactory.newInstance();
+        _factory.setURIResolver(aResolver);
+    }
+
+    /**
+     * Constructs the XSLT processor.
+     * 
+     */
+    public XslTransformer() {
+        _factory = TransformerFactory.newInstance();
+    }
+
+    /**
+     * Resolves an XSLT based on URI. 
+     * @param aXslt XSLT to resolve, 
+     * @return Source for the XSLT
+     * @throws TransformerException In case the XSLT cannot be found. 
+     */
+    public Source resolve(String aXslt) throws TransformerException {
+        URIResolver resolver = _factory.getURIResolver();
+        if (resolver == null) {
+            if (new File(aXslt).canRead()) {
+                try {
+                    return new StreamSource(new FileResource(new File(aXslt))
+                            .getInputStream());
+                } catch (IOException e) {
+                    throw new TransformerException(e.getMessage(), e);
+                }
+            } else {
+                throw new TransformerException("Cannot read '" + aXslt + "'"); 
+            }
+        }
+        return resolver.resolve(aXslt, "");
+    }
+
+    /**
+     * Transforms a DOM document into another DOM document using a given XSLT
+     * transformation.
+     * 
+     * @param aDocument
+     *            Document to transform.
+     * @param aXslt
+     *            XSLT to use.
+     * @return Transformed document.
+     * @throws IOException
+     *             In case of problems reading resources.
+     * @throws TransformerException
+     *             In case transformation fails.
+     */
+    public Document transform(Document aDocument, Source aXslt)
+            throws IOException, TransformerException {
+        Source source = new DOMSource(aDocument);
+        DOMResult result = new DOMResult();
+        transform(source, result, aXslt);
+        return (Document) result.getNode();
+    }
+
+    /**
+     * Transforms a document using XSLT.
+     * 
+     * @param aDocument
+     *            Document to transform.
+     * @param aXslt
+     *            XSLT to use.
+     * @return Transformed document.
+     * @throws IOException
+     *             In case of problems reading resources.
+     * @throws TransformerException
+     *             In case transformation fails.
+     */
+    public Document transform(byte[] aDocument, Source aXslt)
+            throws IOException, TransformerException {
+        Source source = new StreamSource(new ByteArrayInputStream(aDocument));
+        DOMResult result = new DOMResult();
+        transform(source, result, aXslt);
+        return (Document) result.getNode();
+    }
+
+    /**
+     * Transforms a document to a text output. This supports XSLT
+     * transformations that result in text documents.
+     * 
+     * @param aDocument
+     *            Document to transform.
+     * @param aXslt
+     *            XSL transformation.
+     * @return Transformed document.
+     */
+    public String textTransform(byte[] aDocument, Source aXslt)
+            throws IOException, TransformerException {
+        Source source = new StreamSource(new ByteArrayInputStream(aDocument));
+        ByteArrayOutputStream os = new ByteArrayOutputStream();
+        StreamResult result = new StreamResult(os);
+        transform(source, result, aXslt);
+        return new String(os.toByteArray());
+    }
+
+    /**
+     * Transforms a document using XSLT.
+     * 
+     * @param aSource
+     *            Document to transform.
+     * @param aResult
+     *            Result of the transformation.
+     * @param aXslt
+     *            XSLT to use.
+     * @throws IOException
+     *             In case of problems reading resources.
+     * @throws TransformerException
+     *             In case transformation fails.
+     */
+    public void transform(Source aSource, Result aResult, Source aXslt)
+            throws IOException, TransformerException {
+        try {
+            Transformer transformer = _factory.newTransformer(aXslt);
+            transformer.transform(aSource, aResult);
+        } catch (TransformerConfigurationException e) {
+            throw new TransformerException(
+                    "Configuration problem of XSLT transformation", e);
+        }
+    }
+}