New project conventions

[lgpl/argeo-commons.git] / org.argeo.util / src / org / argeo / util / CsvWriter.java

diff --git a/org.argeo.util/src/org/argeo/util/CsvWriter.java b/org.argeo.util/src/org/argeo/util/CsvWriter.java
new file mode 100644 (file)
index 0000000..d90f474
--- /dev/null
+++ b/org.argeo.util/src/org/argeo/util/CsvWriter.java
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2007-2012 Argeo GmbH
+ *
+ * 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.argeo.util;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.UnsupportedEncodingException;
+import java.io.Writer;
+import java.util.Iterator;
+import java.util.List;
+
+import org.argeo.ArgeoException;
+
+/** Write in CSV format. */
+public class CsvWriter {
+       private final Writer out;
+
+       private char separator = ',';
+       private char quote = '\"';
+
+       /**
+        * Creates a CSV writer.
+        * 
+        * @param out
+        *            the stream to write to. Caller is responsible for closing it.
+        */
+       public CsvWriter(OutputStream out) {
+               this.out = new OutputStreamWriter(out);
+       }
+
+       /**
+        * Creates a CSV writer.
+        * 
+        * @param out
+        *            the stream to write to. Caller is responsible for closing it.
+        */
+       public CsvWriter(OutputStream out, String encoding) {
+               try {
+                       this.out = new OutputStreamWriter(out, encoding);
+               } catch (UnsupportedEncodingException e) {
+                       throw new ArgeoException("Cannot initialize CSV writer", e);
+               }
+       }
+
+       /**
+        * Write a CSV line. Also used to write a header if needed (this is
+        * transparent for the CSV writer): simply call it first, before writing the
+        * lines.
+        */
+       public void writeLine(List<?> tokens) {
+               try {
+                       Iterator<?> it = tokens.iterator();
+                       while (it.hasNext()) {
+                               writeToken(it.next().toString());
+                               if (it.hasNext())
+                                       out.write(separator);
+                       }
+                       out.write('\n');
+                       out.flush();
+               } catch (IOException e) {
+                       throw new ArgeoException("Could not write " + tokens, e);
+               }
+       }
+
+       /**
+        * Write a CSV line. Also used to write a header if needed (this is
+        * transparent for the CSV writer): simply call it first, before writing the
+        * lines.
+        */
+       public void writeLine(Object[] tokens) {
+               try {
+                       for (int i = 0; i < tokens.length; i++) {
+                               if (tokens[i] == null) {
+                                       // TODO configure how to deal with null
+                                       writeToken("");
+                               } else {
+                                       writeToken(tokens[i].toString());
+                               }
+                               if (i != (tokens.length - 1))
+                                       out.write(separator);
+                       }
+                       out.write('\n');
+                       out.flush();
+               } catch (IOException e) {
+                       throw new ArgeoException("Could not write " + tokens, e);
+               }
+       }
+
+       protected void writeToken(String token) throws IOException {
+               // +2 for possible quotes, another +2 assuming there would be an already
+               // quoted string where quotes needs to be duplicated
+               // another +2 for safety
+               // we don't want to increase buffer size while writing
+               StringBuffer buf = new StringBuffer(token.length() + 6);
+               char[] arr = token.toCharArray();
+               boolean shouldQuote = false;
+               for (char c : arr) {
+                       if (!shouldQuote) {
+                               if (c == separator)
+                                       shouldQuote = true;
+                               if (c == '\n')
+                                       shouldQuote = true;
+                       }
+
+                       if (c == quote) {
+                               shouldQuote = true;
+                               // duplicate quote
+                               buf.append(quote);
+                       }
+
+                       // generic case
+                       buf.append(c);
+               }
+
+               if (shouldQuote == true)
+                       out.write(quote);
+               out.write(buf.toString());
+               if (shouldQuote == true)
+                       out.write(quote);
+       }
+
+       public void setSeparator(char separator) {
+               this.separator = separator;
+       }
+
+       public void setQuote(char quote) {
+               this.quote = quote;
+       }
+
+}