1 files changed, 167 insertions, 0 deletions
diff --git a/velocity-engine-core/src/main/java/org/apache/velocity/util/StringBuilderWriter.java b/velocity-engine-core/src/main/java/org/apache/velocity/util/StringBuilderWriter.java
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+++ b/velocity-engine-core/src/main/java/org/apache/velocity/util/StringBuilderWriter.java
@@ -0,0 +1,167 @@
+/*
+ * 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.velocity.util;
+
+import java.io.Serializable;
+import java.io.Writer;
+
+/**
+ * {@link Writer} implementation that outputs to a {@link StringBuilder}.
+ * <p>
+ * <strong>NOTE:</strong> This implementation, as an alternative to
+ * <code>java.io.StringWriter</code>, provides an <i>un-synchronized</i>
+ * (i.e. for use in a single thread) implementation for better performance.
+ * For safe usage with multiple {@link Thread}s then
+ * <code>java.io.StringWriter</code> should be used.</p>
+ *
+ * <p>(borrowed from commons.io project)</p>
+ *
+ * @version $Id$
+ * @since 2.0
+ */
+public class StringBuilderWriter extends Writer implements Serializable {
+
+    private static final long serialVersionUID = -146927496096066153L;
+    private final StringBuilder builder;
+
+    /**
+     * Constructs a new {@link StringBuilder} instance with default capacity.
+     */
+    public StringBuilderWriter() {
+        this.builder = new StringBuilder();
+    }
+
+    /**
+     * Constructs a new {@link StringBuilder} instance with the specified capacity.
+     *
+     * @param capacity The initial capacity of the underlying {@link StringBuilder}
+     */
+    public StringBuilderWriter(final int capacity) {
+        this.builder = new StringBuilder(capacity);
+    }
+
+    /**
+     * Constructs a new instance with the specified {@link StringBuilder}.
+     *
+     * <p>If {@code builder} is null a new instance with default capacity will be created.</p>
+     *
+     * @param builder The String builder. May be null.
+     */
+    public StringBuilderWriter(final StringBuilder builder) {
+        this.builder = builder != null ? builder : new StringBuilder();
+    }
+
+    /**
+     * Appends a single character to this Writer.
+     *
+     * @param value The character to append
+     * @return This writer instance
+     */
+    @Override
+    public Writer append(final char value) {
+        builder.append(value);
+        return this;
+    }
+
+    /**
+     * Appends a character sequence to this Writer.
+     *
+     * @param value The character to append
+     * @return This writer instance
+     */
+    @Override
+    public Writer append(final CharSequence value) {
+        builder.append(value);
+        return this;
+    }
+
+    /**
+     * Appends a portion of a character sequence to the {@link StringBuilder}.
+     *
+     * @param value The character to append
+     * @param start The index of the first character
+     * @param end The index of the last character + 1
+     * @return This writer instance
+     */
+    @Override
+    public Writer append(final CharSequence value, final int start, final int end) {
+        builder.append(value, start, end);
+        return this;
+    }
+
+    /**
+     * Closing this writer has no effect.
+     */
+    @Override
+    public void close() {
+        // no-op
+    }
+
+    /**
+     * Flushing this writer has no effect.
+     */
+    @Override
+    public void flush() {
+        // no-op
+    }
+
+
+    /**
+     * Writes a String to the {@link StringBuilder}.
+     *
+     * @param value The value to write
+     */
+    @Override
+    public void write(final String value) {
+        if (value != null) {
+            builder.append(value);
+        }
+    }
+
+    /**
+     * Writes a portion of a character array to the {@link StringBuilder}.
+     *
+     * @param value The value to write
+     * @param offset The index of the first character
+     * @param length The number of characters to write
+     */
+    @Override
+    public void write(final char[] value, final int offset, final int length) {
+        if (value != null) {
+            builder.append(value, offset, length);
+        }
+    }
+
+    /**
+     * Returns the underlying builder.
+     *
+     * @return The underlying builder
+     */
+    public StringBuilder getBuilder() {
+        return builder;
+    }
+
+    /**
+     * Returns {@link StringBuilder#toString()}.
+     *
+     * @return The contents of the String builder.
+     */
+    @Override
+    public String toString() {
+        return builder.toString();
+    }
+}