juneau-core/juneau-marshall/src/main/java/org/apache/juneau/DefaultFilteringObjectMap.java

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// * 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                                                                             *
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// ***************************************************************************************************************************
package org.apache.juneau;

import java.lang.reflect.*;
import java.util.*;

/**
 * Subclass of {@link ObjectMap} that avoids adding common default values.
 */
public class DefaultFilteringObjectMap extends ObjectMap {

	private static final long serialVersionUID = 1L;

	/**
	 * Constructor.
	 *
	 * @param m
	 * 	The object map to copy from.
	 * 	<br>Can be <jk>null</jk>.
	 */
	public DefaultFilteringObjectMap(ObjectMap m) {
		super();
		appendAll(m);
	}

	/**
	 * Constructor.
	 */
	public DefaultFilteringObjectMap() {
		super();
	}

	@Override /* ObjectMap */
	public ObjectMap append(String key, Object value) {
		if (! shouldSkip(value))
			super.append(key, value);
		return this;
	}

	/**
	 * Returns <jk>true</jk> if the specified value should be skipped.
	 *
	 * @param value The value to check.
	 * @return <jk>true</jk> if the specified value should be skipped.
	 */
	protected boolean shouldSkip(Object value) {
		return
			value == null
			|| (value instanceof Boolean && value.equals(false))
			|| (value instanceof Number && ((Number)value).intValue() == -1)
			|| (value.getClass().isArray() && Array.getLength(value) == 0)
			|| (value instanceof Map && ((Map<?,?>)value).isEmpty())
			|| (value instanceof Collection && ((Collection<?>)value).isEmpty());

	}
}