LMS-2612 Introducing CommaSeparatedListBuilder

SVN: 24581

common/source/java/ch/systemsx/cisd/common/utilities/CommaSeparatedListBuilder.java

+/*
+ * Copyright 2012 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.utilities;
+
+import java.util.List;
+
+/**
+ * Builder of a comma-separated list of stringified objects.
+ *
+ * @author Franz-Josef Elmer
+ */
+public class CommaSeparatedListBuilder
+{
+    /**
+     * Creates comma-separated list from specified objects.
+     */
+    public static String toString(Object... objects)
+    {
+        CommaSeparatedListBuilder listBuilder = new CommaSeparatedListBuilder();
+        for (Object object : objects)
+        {
+            listBuilder.append(object);
+        }
+        return listBuilder.toString();
+    }
+    
+    /**
+     * Creates comma-separated list from specified objects.
+     */
+    public static String toString(List<?> objects)
+    {
+        CommaSeparatedListBuilder listBuilder = new CommaSeparatedListBuilder();
+        for (Object object : objects)
+        {
+            listBuilder.append(object);
+        }
+        return listBuilder.toString();
+    }
+    
+    private final StringBuilder builder = new StringBuilder();
+    
+    /**
+     * Appends specified object.
+     */
+    public void append(Object object)
+    {
+        if (builder.length() > 0)
+        {
+            builder.append(", ");
+        }
+        builder.append(object);
+    }
+
+    /**
+     * Returns comma-separated list of appended objects.
+     */
+    @Override
+    public String toString()
+    {
+        return builder.toString();
+    }
+}

common/sourceTest/java/ch/systemsx/cisd/common/utilities/CommaSeparatedListBuilderTest.java

+/*
+ * Copyright 2012 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.utilities;
+
+import java.util.Arrays;
+
+import org.testng.AssertJUnit;
+import org.testng.annotations.Test;
+
+/**
+ * 
+ *
+ * @author Franz-Josef Elmer
+ */
+public class CommaSeparatedListBuilderTest extends AssertJUnit
+{
+
+    @Test
+    public void testNoObjectsAppended()
+    {
+        CommaSeparatedListBuilder builder = new CommaSeparatedListBuilder();
+        
+        assertEquals("", builder.toString());
+    }
+
+    @Test
+    public void testOneObjectAppended()
+    {
+        CommaSeparatedListBuilder builder = new CommaSeparatedListBuilder();
+        builder.append("hello");
+        
+        assertEquals("hello", builder.toString());
+    }
+    
+    @Test
+    public void testTwoObjectsAppended()
+    {
+        CommaSeparatedListBuilder builder = new CommaSeparatedListBuilder();
+        builder.append("hello");
+        builder.append(null);
+        
+        assertEquals("hello, null", builder.toString());
+    }
+    
+    @Test
+    public void testToStringArray()
+    {
+        assertEquals("hello, 42", CommaSeparatedListBuilder.toString("hello", 42));
+    }
+    
+    @Test
+    public void testToStringList()
+    {
+        assertEquals("hello, 42", CommaSeparatedListBuilder.toString(Arrays.<Object>asList("hello", 42)));
+    }
+    
+}