LMS-1888 IContentProvider and ContentProviderBasedContent introduced

SVN: 18893

common/source/java/ch/systemsx/cisd/common/io/ContentProviderBasedContent.java

+/*
+ * Copyright 2010 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.io;
+
+import java.io.InputStream;
+
+/**
+ * Content based on a {@link IContentProvider}.
+ *
+ * @author Franz-Josef Elmer
+ */
+public class ContentProviderBasedContent implements IContent
+{
+    private final IContentProvider contentProvider;
+    private IContent content;
+
+    /**
+     * Creates an instance for specified content provider.
+     */
+    public ContentProviderBasedContent(IContentProvider contentProvider)
+    {
+        this.contentProvider = contentProvider;
+    }
+
+    public String tryGetName()
+    {
+        return getContent().tryGetName();
+    }
+
+    public long getSize()
+    {
+        return getContent().getSize();
+    }
+
+    public boolean exists()
+    {
+        return getContent().exists();
+    }
+
+    public InputStream getInputStream()
+    {
+        return getContent().getInputStream();
+    }
+    
+    private IContent getContent()
+    {
+        if (content == null)
+        {
+            content = contentProvider.getContent();
+        }
+        return content;
+    }
+    
+}

common/source/java/ch/systemsx/cisd/common/io/IContentProvider.java

+/*
+ * Copyright 2010 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.io;
+
+/**
+ * Provider of {@link IContent} instance.
+ *
+ * @author Franz-Josef Elmer
+ */
+public interface IContentProvider
+{
+    /**
+     * Returns content.
+     */
+    public IContent getContent();
+}