Integrate Krazo Facelets View Engine with LibreCCM themes

ccm-core/src/main/java/org/libreccm/mvc/facelets/CcmThemeUrlConnection.java

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+/*
+ * Copyright (C) 2020 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.libreccm.mvc.facelets;
+
+import org.libreccm.theming.ThemeInfo;
+import org.libreccm.theming.ThemeVersion;
+import org.libreccm.theming.Themes;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.Arrays;
+import java.util.Objects;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+class CcmThemeUrlConnection extends URLConnection {
+
+    private final Themes themes;
+
+    private final String path;
+
+    private ThemeInfo themeInfo;
+
+    private String filePath;
+
+    public CcmThemeUrlConnection(final Themes themes, final URL url) {
+        super(url);
+        this.themes = themes;
+
+        final String urlStr = url.toString();
+
+        if (urlStr.startsWith("/")) {
+            path = urlStr.substring(1);
+        } else {
+            path = urlStr;
+        }
+    }
+
+    @Override
+    public void connect() throws IOException {
+        final String[] tokens = path.split("/");
+        if (tokens.length >= 4) {
+            final String themeName = tokens[1];
+            final ThemeVersion version = ThemeVersion.valueOf(tokens[2]);
+            filePath = String.join(
+                "/",
+                Arrays.copyOfRange(
+                    tokens, 3, tokens.length, String[].class
+                )
+            );
+
+            themeInfo = themes.getTheme(themeName, version)
+                .orElseThrow(() -> new IOException(
+                String.format(
+                    "Theme %s is available as  %s version.",
+                    themeName,
+                    Objects.toString(version)
+                )));
+        } else {
+            throw new IOException(
+                "Illegal URL for loading a facelets template from a theme."
+            );
+        }
+
+    }
+
+    @Override
+    public InputStream getInputStream() throws IOException {
+        return themes
+            .getFileFromTheme(themeInfo, filePath)
+            .orElseThrow(
+                () -> new IOException(
+                    String.format(
+                        "Template %s not found in %s version of the theme %s.",
+                        filePath,
+                        themeInfo.getVersion(),
+                        themeInfo.getName()
+                    )
+                )
+            );
+
+    }
+
+}

ccm-core/src/main/java/org/libreccm/mvc/facelets/CcmThemeUrlStreamHandler.java

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+/*
+ * Copyright (C) 2020 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.libreccm.mvc.facelets;
+
+import org.libreccm.theming.Themes;
+
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.net.URLStreamHandler;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+class CcmThemeUrlStreamHandler extends URLStreamHandler {
+
+    private final Themes themes;
+    
+    public CcmThemeUrlStreamHandler(final Themes themes) {
+        this.themes = themes;
+    }
+    
+    @Override
+    protected URLConnection openConnection(final URL url) throws IOException {
+        return new CcmThemeUrlConnection(themes, url);
+    }
+    
+}

ccm-core/src/main/java/org/libreccm/mvc/facelets/CcmThemeViewResource.java

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+/*
+ * Copyright (C) 2020 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.libreccm.mvc.facelets;
+
+import org.libreccm.core.UnexpectedErrorException;
+import org.libreccm.theming.Themes;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import javax.faces.application.ViewResource;
+
+/**
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+class CcmThemeViewResource extends ViewResource {
+
+    private final String path;
+
+    private final Themes themes;
+
+    public CcmThemeViewResource(final Themes themes, final String path) {
+        this.themes = themes;
+        this.path = path;
+    }
+
+    @Override
+    public URL getURL() {
+        try {
+            return new URL(
+                "libreccm",
+                null,
+                0,
+                path,
+                new CcmThemeUrlStreamHandler(themes)
+            );
+        } catch (MalformedURLException ex) {
+            throw new UnexpectedErrorException(ex);
+        }
+    }
+
+}

ccm-core/src/main/java/org/libreccm/mvc/facelets/CcmViewResourceHandler.java

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+/*
+ * Copyright (C) 2020 LibreCCM Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+package org.libreccm.mvc.facelets;
+
+import org.libreccm.theming.Themes;
+
+import javax.faces.application.ResourceHandler;
+import javax.faces.application.ResourceHandlerWrapper;
+import javax.faces.application.ViewResource;
+import javax.faces.context.FacesContext;
+import javax.inject.Inject;
+
+/**
+ * A Facelets resource handler that loads Facelets templates from LibreCCM
+ * themes.
+ *
+ * This handler only works for view resources. Only resource path which are
+ * starting with {@code @themes} or {@code /@themes} are used processed. All
+ * other paths are delegated to the wrapped resource handler.
+ * 
+ * To enable this resource handler to following snippet must be present in the
+ * {@code faces-config.xml} file of the WAR (bundle):
+ * 
+ * <pre>
+ * &lt;application&gt;
+        &tl;resource-handler&gt;org.libreccm.ui.CcmFaceletsResourceHandler&lt;/resource-handler&gt;
+    &lt;/application&gt;
+
+ * </pre>
+ *
+ * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
+ */
+public class CcmViewResourceHandler extends ResourceHandlerWrapper {
+
+    @Inject
+    private Themes themes;
+
+    private final ResourceHandler wrapped;
+
+    public CcmViewResourceHandler(final ResourceHandler wrapped) {
+        super(wrapped);
+        this.wrapped = wrapped;
+    }
+
+    @Override
+    public ViewResource createViewResource(
+        final FacesContext context, final String path
+    ) {
+        if (path.startsWith("@themes") || path.startsWith("/@themes")) {
+            return new CcmThemeViewResource(themes, path);
+        } else {
+            return super.createViewResource(context, path);
+        }
+    }
+
+}