com.adaptris.core.MetadataElement.java Source code

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Here is the source code for com.adaptris.core.MetadataElement.java

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/*
 * Copyright 2015 Adaptris Ltd.
 * 
 * Licensed 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 com.adaptris.core;

import static org.apache.commons.lang.StringUtils.isEmpty;

import com.adaptris.annotation.GenerateBeanInfo;
import com.adaptris.util.GuidGenerator;
import com.adaptris.util.KeyValuePair;
import com.thoughtworks.xstream.annotations.XStreamAlias;

/**
 * <p>
 * A key-value pair of <code>String</code> metadata. Instances of this class are used by
 * implementations of <code>AdaptrisMessage</code> to store metadata. Semantic equality of
 * <code>MetadataElement</code> s is based on the value of the 'key' only.
 * </p>
 * 
 * @config metadata-element
 */
@XStreamAlias("metadata-element")
@GenerateBeanInfo
public class MetadataElement extends KeyValuePair implements Cloneable {

    private static transient final GuidGenerator UUID = new GuidGenerator();
    /**
     *
     */
    private static final long serialVersionUID = 2013111201L;

    /**
     * Default Constructor.
     * <p>
     * By default, each metadata element is given a unique key using {@link GuidGenerator#getUUID()}, as {@link KeyValuePair} only
     * enforces null checking, but metadata elements must have a non-empty key.
     * </p>
     */
    public MetadataElement() {
        setKey(UUID.getUUID());
    }

    /**
     * <p>
     * Creates a new instance.
     * </p>
     *
     * @param kp the keyvalue pair this metadata element should wrap
     */
    public MetadataElement(KeyValuePair kp) {
        this(kp.getKey(), kp.getValue());
    }

    /**
     * <p>
     * Creates a new instance.
     * </p>
     *
     * @param key may not be null or empty
     * @param value may not be null or empty
     */
    public MetadataElement(String key, String value) {
        this();
        setKey(key);
        setValue(value);
    }

    /**
     * <p>
     * Sets the 'key'.
     * </p>
     * 
     * @param key may not be null or the empty string.
     */
    @Override
    public void setKey(String key) {
        if (isEmpty(key)) {
            throw new IllegalArgumentException("illegal key [" + key + "]");
        } else {
            super.setKey(key);
        }
    }

    /**
     * @see java.lang.Object#clone()
     */
    @Override
    public Object clone() throws CloneNotSupportedException {
        MetadataElement obj = (MetadataElement) super.clone();
        obj.setKey(getKey());
        obj.setValue(getValue());
        return obj;
    }
}