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006 * to you under the Apache License, Version 2.0 (the *
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019
020 package org.apache.james.mime4j.stream;
021
022 import org.apache.james.mime4j.MimeException;
023
024 /**
025 * Body descriptor builders are intended to construct {@link BodyDescriptor} instances from
026 * multiple unstructured {@link RawField}s.
027 * <p/>
028 * Body descriptor builders are stateful and modal as they have to store intermediate results
029 * between method invocations and also rely on a particular sequence of method invocations
030 * (the mode of operation).
031 * <p/>
032 * Consumers are expected to interact with body descriptor builders in the following way:
033 * <ul>
034 * <li>Invoke {@link #reset()} method in order to reset builder's internal state and make it
035 * ready to start the process of building a new {@link BodyDescriptor}.</li>
036 * <li>Invoke {@link #addField(RawField)} multiple times method in order to collect
037 * necessary details for building a body descriptor. The builder can optionally
038 * transform the unstructured field given an an input into a structured one and return
039 * an instance {@link Field} that also implements a richer interface for a particular type
040 * of fields such as <code>Content-Type</code>. The builder can also return <code>null</code>
041 * if the field is to be ignored</li>
042 * <li>Optionally invoke {@link #newChild()} for each embedded body of content. Please note that
043 * the resultant {@link BodyDescriptorBuilder}} child instance can inherit some its parent
044 * properties such as MIME type.</li>
045 * <li>Invoke {@link #build()()} method in order to generate a {@link BodyDescriptor}} instance
046 * based on the internal state of the builder.</li>
047 * </ul>
048 */
049 public interface BodyDescriptorBuilder {
050
051 /**
052 * Resets the internal state of the builder making it ready to process new input.
053 */
054 void reset();
055
056 /**
057 * Updates builder's internal state by adding a new field. The builder can optionally
058 * transform the unstructured field given an an input into a structured one and return
059 * an instance {@link Field} that also implements a richer interface for a particular type
060 * of fields such as <code>Content-Type</code>. The builder can also return <code>null</code>
061 * if the field is to be ignored.
062 */
063 Field addField(RawField field) throws MimeException;
064
065 /**
066 * Builds an instance of {@link BodyDescriptor} based on the internal state.
067 */
068 BodyDescriptor build();
069
070 /**
071 * Creates an instance of {@link BodyDescriptorBuilder} to be used for processing of an
072 * embedded content body. Please the child instance can inherit some of its parent properties
073 * such as MIME type.
074 */
075 BodyDescriptorBuilder newChild();
076
077 }