1 files changed, 154 insertions, 0 deletions
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/SimpleXmlTransfer.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/SimpleXmlTransfer.java
new file mode 100644
index 000000000..20ac2033e
--- /dev/null
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/SimpleXmlTransfer.java
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
+ *
+ * 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 com.android.ide.eclipse.adt.internal.editors.layout.gle2;
+
+import com.android.ide.eclipse.adt.internal.editors.descriptors.ElementDescriptor;
+import com.android.ide.eclipse.adt.internal.editors.layout.descriptors.ViewElementDescriptor;
+
+import org.eclipse.swt.dnd.ByteArrayTransfer;
+import org.eclipse.swt.dnd.TransferData;
+
+import java.io.UnsupportedEncodingException;
+
+/**
+ * A d'n'd {@link Transfer} class that can transfer a <em>simplified</em> XML fragment
+ * to transfer elements and their attributes between {@link LayoutCanvas}.
+ * <p/>
+ * The implementation is based on the {@link ByteArrayTransfer} and what we transfer
+ * is text with the following fixed format:
+ * <p/>
+ * <pre>
+ * {element-name element-property ...
+ *  attrib_name="attrib_value"
+ *  attrib2="..."
+ *  {...inner elements...
+ *  }
+ * }
+ * {...next element...
+ * }
+ *
+ * </pre>
+ * The format has nothing to do with XML per se, except for the fact that the
+ * transfered content represents XML elements and XML attributes.
+ *
+ * <p/>
+ * The detailed syntax is:
+ * <pre>
+ * - ELEMENT     := {NAME PROPERTY*\nATTRIB_LINE*ELEMENT*}\n
+ * - PROPERTY    := $[A-Z]=[^ ]*
+ * - NAME        := [^\n=]+
+ * - ATTRIB_LINE := @URI:NAME=[^\n]*\n
+ * </pre>
+ *
+ * Elements are represented by {@link SimpleElement}s and their attributes by
+ * {@link SimpleAttribute}s, all of which have very specific properties that are
+ * specifically limited to our needs for drag'n'drop.
+ */
+final class SimpleXmlTransfer extends ByteArrayTransfer {
+
+    // Reference: http://www.eclipse.org/articles/Article-SWT-DND/DND-in-SWT.html
+
+    private static final String TYPE_NAME = "android.ADT.simple.xml.transfer.1";    //$NON-NLS-1$
+    private static final int TYPE_ID = registerType(TYPE_NAME);
+    private static final SimpleXmlTransfer sInstance = new SimpleXmlTransfer();
+
+    /** Private constructor. Use {@link #getInstance()} to retrieve the singleton instance. */
+    private SimpleXmlTransfer() {
+        // pass
+    }
+
+    /** Returns the singleton instance. */
+    public static SimpleXmlTransfer getInstance() {
+        return sInstance;
+    }
+
+    /**
+     * Helper method that returns the FQCN transfered for the given {@link ElementDescriptor}.
+     * <p/>
+     * If the descriptor is a {@link ViewElementDescriptor}, the transfered data is the FQCN
+     * of the Android View class represented (e.g. "android.widget.Button").
+     * For any other non-null descriptor, the XML name is used.
+     * Otherwise it is null.
+     *
+     * @param desc The {@link ElementDescriptor} to transfer.
+     * @return The FQCN, XML name or null.
+     */
+    public static String getFqcn(ElementDescriptor desc) {
+        if (desc instanceof ViewElementDescriptor) {
+            return ((ViewElementDescriptor) desc).getFullClassName();
+        } else if (desc != null) {
+            return desc.getXmlName();
+        }
+
+        return null;
+    }
+
+    @Override
+    protected int[] getTypeIds() {
+        return new int[] { TYPE_ID };
+    }
+
+    @Override
+    protected String[] getTypeNames() {
+        return new String[] { TYPE_NAME };
+    }
+
+    /** Transforms a array of {@link SimpleElement} into a native data transfer. */
+    @Override
+    protected void javaToNative(Object object, TransferData transferData) {
+        if (object == null || !(object instanceof SimpleElement[])) {
+            return;
+        }
+
+        if (isSupportedType(transferData)) {
+            StringBuilder sb = new StringBuilder();
+            for (SimpleElement e : (SimpleElement[]) object) {
+                sb.append(e.toString());
+            }
+            String data = sb.toString();
+
+            try {
+                byte[] buf = data.getBytes("UTF-8");  //$NON-NLS-1$
+                super.javaToNative(buf, transferData);
+            } catch (UnsupportedEncodingException e) {
+                // unlikely; ignore
+            }
+        }
+    }
+
+    /**
+     * Recreates an array of {@link SimpleElement} from a native data transfer.
+     *
+     * @return An array of {@link SimpleElement} or null. The array may be empty.
+     */
+    @Override
+    protected Object nativeToJava(TransferData transferData) {
+        if (isSupportedType(transferData)) {
+            byte[] buf = (byte[]) super.nativeToJava(transferData);
+            if (buf != null && buf.length > 0) {
+                try {
+                    String s = new String(buf, "UTF-8"); //$NON-NLS-1$
+                    return SimpleElement.parseString(s);
+                } catch (UnsupportedEncodingException e) {
+                    // unlikely to happen, but still possible
+                }
+            }
+        }
+
+        return null;
+    }
+}