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/*
* Copyright (c) 2009-2014 JGoodies Software GmbH. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* o Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* o Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* o Neither the name of JGoodies Software GmbH nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.jgoodies.common.format;
import static com.jgoodies.common.base.Preconditions.checkNotNull;
import static com.jgoodies.common.internal.Messages.MUST_NOT_BE_NULL;
import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.ParsePosition;
import com.jgoodies.common.base.Objects;
import com.jgoodies.common.base.Strings;
/**
* Wraps a given {@code NumberFormat} and adds behavior to convert to/from
* the empty string. Therefore it holds an empty value that is
* mapped to/from the empty string. The {@code #format} result
* of the empty value is the empty string, and the {@code #parse}
* result of the empty string is the empty value. In all other cases
* the formatting and parsing is forwarded to the wrapped NumberFormat.
*
* Examples:
* new EmptyNumberFormat(NumberFormat().getInstance());
* new EmptyNumberFormat(NumberFormat().getIntegerInstance(), -1);
*
*
* @author Karsten Lentzsch
*/
public final class EmptyNumberFormat extends NumberFormat {
private final NumberFormat delegate;
private final Number emptyValue;
// Instance Creation ****************************************************
/**
* Constructs an EmptyNumberFormat that wraps the given mandatory format
* to convert {@code null} to the empty string and vice versa.
*
* @param delegate the format that handles the standard cases
*
* @throws NullPointerException if {@code delegate} is {@code null}
*/
public EmptyNumberFormat(NumberFormat delegate) {
this(delegate, null);
}
/**
* Constructs an EmptyNumberFormat that wraps the given mandatory format
* to convert the given {@code emptyValue} to the empty string
* and vice versa.
*
* @param delegate the format that handles non-{@code null} values
* @param emptyValue the representation of the empty string
*
* @throws NullPointerException if {@code delegate} is {@code null}
*/
public EmptyNumberFormat(NumberFormat delegate, int emptyValue) {
this(delegate, Integer.valueOf(emptyValue));
}
/**
* Constructs an EmptyNumberFormat that wraps the given mandatory format
* to convert the given {@code emptyValue} to the empty string
* and vice versa.
*
* @param delegate the format that handles non-{@code null} values
* @param emptyValue the representation of the empty string
*
* @throws NullPointerException if {@code delegate} is {@code null}
*/
public EmptyNumberFormat(NumberFormat delegate, Number emptyValue) {
this.delegate = checkNotNull(delegate, MUST_NOT_BE_NULL, "delegate format");
this.emptyValue = emptyValue;
}
// Overriding Superclass Behavior *****************************************
/**
* {@inheritDoc}
*
* If {@code obj} is equal to the emptyValue,
* {@code toAppendTo} is returned. Otherwise the format
* is forwarded to the delegate.
*/
@Override
public StringBuffer format(Object obj, StringBuffer toAppendTo,
FieldPosition pos) {
return Objects.equals(obj, emptyValue)
? toAppendTo
: delegate.format(obj, toAppendTo, pos);
}
@Override
public StringBuffer format(double number,
StringBuffer toAppendTo,
FieldPosition pos) {
return delegate.format(number, toAppendTo, pos);
}
@Override
public StringBuffer format(long number,
StringBuffer toAppendTo,
FieldPosition pos) {
return delegate.format(number, toAppendTo, pos);
}
/**
* {@inheritDoc}
*
* If {@code source} is empty or whitespace, the emptyValue
* is returned. Otherwise parsing is forwarded to the delegate
* - indirectly via {@link #parse(String, ParsePosition)}.
*/
@Override
public Object parseObject(String source) throws ParseException {
return Strings.isBlank(source)
? emptyValue
: super.parseObject(source);
}
/**
* {@inheritDoc}
*
* If {@code source} is empty or whitespace, the emptyValue
* is returned. Otherwise parsing is forwarded to the delegate
* - indirectly via {@link #parse(String, ParsePosition)}.
*/
@Override
public Number parse(String source) throws ParseException {
return Strings.isBlank(source)
? emptyValue
: super.parse(source);
}
@Override
public Number parse(String source, ParsePosition pos) {
return delegate.parse(source, pos);
}
}