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diff --git a/src/main/java/org/apache/commons/math3/fraction/AbstractFormat.java b/src/main/java/org/apache/commons/math3/fraction/AbstractFormat.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.commons.math3.fraction;
+
+import org.apache.commons.math3.exception.NullArgumentException;
+import org.apache.commons.math3.exception.util.LocalizedFormats;
+
+import java.io.Serializable;
+import java.text.FieldPosition;
+import java.text.NumberFormat;
+import java.text.ParsePosition;
+import java.util.Locale;
+
+/**
+ * Common part shared by both {@link FractionFormat} and {@link BigFractionFormat}.
+ *
+ * @since 2.0
+ */
+public abstract class AbstractFormat extends NumberFormat implements Serializable {
+
+    /** Serializable version identifier. */
+    private static final long serialVersionUID = -6981118387974191891L;
+
+    /** The format used for the denominator. */
+    private NumberFormat denominatorFormat;
+
+    /** The format used for the numerator. */
+    private NumberFormat numeratorFormat;
+
+    /**
+     * Create an improper formatting instance with the default number format for the numerator and
+     * denominator.
+     */
+    protected AbstractFormat() {
+        this(getDefaultNumberFormat());
+    }
+
+    /**
+     * Create an improper formatting instance with a custom number format for both the numerator and
+     * denominator.
+     *
+     * @param format the custom format for both the numerator and denominator.
+     */
+    protected AbstractFormat(final NumberFormat format) {
+        this(format, (NumberFormat) format.clone());
+    }
+
+    /**
+     * Create an improper formatting instance with a custom number format for the numerator and a
+     * custom number format for the denominator.
+     *
+     * @param numeratorFormat the custom format for the numerator.
+     * @param denominatorFormat the custom format for the denominator.
+     */
+    protected AbstractFormat(
+            final NumberFormat numeratorFormat, final NumberFormat denominatorFormat) {
+        this.numeratorFormat = numeratorFormat;
+        this.denominatorFormat = denominatorFormat;
+    }
+
+    /**
+     * Create a default number format. The default number format is based on {@link
+     * NumberFormat#getNumberInstance(java.util.Locale)}. The only customization is the maximum
+     * number of BigFraction digits, which is set to 0.
+     *
+     * @return the default number format.
+     */
+    protected static NumberFormat getDefaultNumberFormat() {
+        return getDefaultNumberFormat(Locale.getDefault());
+    }
+
+    /**
+     * Create a default number format. The default number format is based on {@link
+     * NumberFormat#getNumberInstance(java.util.Locale)}. The only customization is the maximum
+     * number of BigFraction digits, which is set to 0.
+     *
+     * @param locale the specific locale used by the format.
+     * @return the default number format specific to the given locale.
+     */
+    protected static NumberFormat getDefaultNumberFormat(final Locale locale) {
+        final NumberFormat nf = NumberFormat.getNumberInstance(locale);
+        nf.setMaximumFractionDigits(0);
+        nf.setParseIntegerOnly(true);
+        return nf;
+    }
+
+    /**
+     * Access the denominator format.
+     *
+     * @return the denominator format.
+     */
+    public NumberFormat getDenominatorFormat() {
+        return denominatorFormat;
+    }
+
+    /**
+     * Access the numerator format.
+     *
+     * @return the numerator format.
+     */
+    public NumberFormat getNumeratorFormat() {
+        return numeratorFormat;
+    }
+
+    /**
+     * Modify the denominator format.
+     *
+     * @param format the new denominator format value.
+     * @throws NullArgumentException if {@code format} is {@code null}.
+     */
+    public void setDenominatorFormat(final NumberFormat format) {
+        if (format == null) {
+            throw new NullArgumentException(LocalizedFormats.DENOMINATOR_FORMAT);
+        }
+        this.denominatorFormat = format;
+    }
+
+    /**
+     * Modify the numerator format.
+     *
+     * @param format the new numerator format value.
+     * @throws NullArgumentException if {@code format} is {@code null}.
+     */
+    public void setNumeratorFormat(final NumberFormat format) {
+        if (format == null) {
+            throw new NullArgumentException(LocalizedFormats.NUMERATOR_FORMAT);
+        }
+        this.numeratorFormat = format;
+    }
+
+    /**
+     * Parses <code>source</code> until a non-whitespace character is found.
+     *
+     * @param source the string to parse
+     * @param pos input/output parsing parameter. On output, <code>pos</code> holds the index of the
+     *     next non-whitespace character.
+     */
+    protected static void parseAndIgnoreWhitespace(final String source, final ParsePosition pos) {
+        parseNextCharacter(source, pos);
+        pos.setIndex(pos.getIndex() - 1);
+    }
+
+    /**
+     * Parses <code>source</code> until a non-whitespace character is found.
+     *
+     * @param source the string to parse
+     * @param pos input/output parsing parameter.
+     * @return the first non-whitespace character.
+     */
+    protected static char parseNextCharacter(final String source, final ParsePosition pos) {
+        int index = pos.getIndex();
+        final int n = source.length();
+        char ret = 0;
+
+        if (index < n) {
+            char c;
+            do {
+                c = source.charAt(index++);
+            } while (Character.isWhitespace(c) && index < n);
+            pos.setIndex(index);
+
+            if (index < n) {
+                ret = c;
+            }
+        }
+
+        return ret;
+    }
+
+    /**
+     * Formats a double value as a fraction and appends the result to a StringBuffer.
+     *
+     * @param value the double value to format
+     * @param buffer StringBuffer to append to
+     * @param position On input: an alignment field, if desired. On output: the offsets of the
+     *     alignment field
+     * @return a reference to the appended buffer
+     * @see #format(Object, StringBuffer, FieldPosition)
+     */
+    @Override
+    public StringBuffer format(
+            final double value, final StringBuffer buffer, final FieldPosition position) {
+        return format(Double.valueOf(value), buffer, position);
+    }
+
+    /**
+     * Formats a long value as a fraction and appends the result to a StringBuffer.
+     *
+     * @param value the long value to format
+     * @param buffer StringBuffer to append to
+     * @param position On input: an alignment field, if desired. On output: the offsets of the
+     *     alignment field
+     * @return a reference to the appended buffer
+     * @see #format(Object, StringBuffer, FieldPosition)
+     */
+    @Override
+    public StringBuffer format(
+            final long value, final StringBuffer buffer, final FieldPosition position) {
+        return format(Long.valueOf(value), buffer, position);
+    }
+}