org.springframework.batch.sample.domain.multiline.AggregateItem.java Source code

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Here is the source code for org.springframework.batch.sample.domain.multiline.AggregateItem.java

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/*
 * Copyright 2006-2014 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.batch.sample.domain.multiline;

/**
 * A wrapper type for an item that is used by {@link AggregateItemReader} to
 * identify the start and end of an aggregate record.
 * 
 * @see AggregateItemReader
 * 
 * @author Dave Syer
 * 
 */
public class AggregateItem<T> {
    @SuppressWarnings("rawtypes")
    private static final AggregateItem FOOTER = new AggregateItem<Object>(false, true) {
        @Override
        public Object getItem() {
            throw new IllegalStateException("Footer record has no item.");
        }
    };

    /**
     * @param <T> the type of item nominally wrapped
     * @return a static {@link AggregateItem} that is a footer.
     */
    @SuppressWarnings("unchecked")
    public static <T> AggregateItem<T> getFooter() {
        return FOOTER;
    }

    @SuppressWarnings("rawtypes")
    private static final AggregateItem HEADER = new AggregateItem<Object>(true, false) {
        @Override
        public Object getItem() {
            throw new IllegalStateException("Header record has no item.");
        }
    };

    /**
     * @param <T> the type of item nominally wrapped
     * @return a static {@link AggregateItem} that is a header.
     */
    @SuppressWarnings("unchecked")
    public static <T> AggregateItem<T> getHeader() {
        return HEADER;
    }

    private T item;

    private boolean footer = false;

    private boolean header = false;

    /**
     * @param item the item to wrap
     */
    public AggregateItem(T item) {
        super();
        this.item = item;
    }

    public AggregateItem(boolean header, boolean footer) {
        this(null);
        this.header = header;
        this.footer = footer;
    }

    /**
     * Accessor for the wrapped item.
     * 
     * @return the wrapped item
     * @throws IllegalStateException if called on a record for which either
     * {@link #isHeader()} or {@link #isFooter()} answers true.
     */
    public T getItem() {
        return item;
    }

    /**
     * Responds true if this record is a footer in an aggregate.
     * @return true if this is the end of an aggregate record.
     */
    public boolean isFooter() {
        return footer;
    }

    /**
     * Responds true if this record is a header in an aggregate.
     * @return true if this is the beginning of an aggregate record.
     */
    public boolean isHeader() {
        return header;
    }

}