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java/org/apache/catalina/util/IOTools.java

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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.catalina.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.Reader;
+import java.io.Writer;
+
+
+/**
+ * Contains commonly needed I/O-related methods
+ *
+ * @author Dan Sandberg
+ */
+public class IOTools {
+    protected static final int DEFAULT_BUFFER_SIZE=4*1024; //4k
+
+    private IOTools() {
+      //Ensure non-instantiability
+    }
+
+    /**
+     * Read input from reader and write it to writer until there is no more
+     * input from reader.
+     *
+     * @param reader the reader to read from.
+     * @param writer the writer to write to.
+     * @param buf the char array to use as a buffer
+     * @throws IOException IO error
+     */
+    public static void flow( Reader reader, Writer writer, char[] buf )
+        throws IOException {
+        int numRead;
+        while ( (numRead = reader.read(buf) ) >= 0) {
+            writer.write(buf, 0, numRead);
+        }
+    }
+
+    /**
+     * Read input from reader and write it to writer until there is no more
+     * input from reader.
+     *
+     * @param reader the reader to read from.
+     * @param writer the writer to write to.
+     * @throws IOException IO error
+     * @see #flow( Reader, Writer, char[] )
+     */
+    public static void flow( Reader reader, Writer writer )
+        throws IOException {
+        char[] buf = new char[DEFAULT_BUFFER_SIZE];
+        flow( reader, writer, buf );
+    }
+
+
+    /**
+     * Read input from input stream and write it to output stream until there is
+     * no more input from input stream using a new buffer of the default size
+     * (4kB).
+     *
+     * @param is input stream the input stream to read from.
+     * @param os output stream the output stream to write to.
+     *
+     * @throws IOException If an I/O error occurs during the copy
+     */
+    public static void flow(InputStream is, OutputStream os) throws IOException {
+        byte[] buf = new byte[DEFAULT_BUFFER_SIZE];
+        int numRead;
+        while ( (numRead = is.read(buf) ) >= 0) {
+            if (os != null) {
+                os.write(buf, 0, numRead);
+            }
+        }
+    }
+
+
+    /**
+     * Read until EOF or the buffer is filled.
+     *
+     * @param is    The source to read from
+     * @param buf   The buffer to write to
+     *
+     * @return The number of bytes read
+     *
+     * @throws IOException If an I/O error occurs during the read
+     */
+    public static int readFully(InputStream is, byte[] buf) throws IOException {
+        int bytesRead = 0;
+        int read;
+        while (bytesRead < buf.length && ((read = is.read(buf, bytesRead, buf.length - bytesRead)) >= 0)) {
+            bytesRead += read;
+        }
+        return bytesRead;
+    }
+}