/****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one *
* or more contributor license agreements. See the NOTICE file *
* 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 *
* *
* 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.apache.james.mime4j.message;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.apache.james.mime4j.MimeException;
import org.apache.james.mime4j.MimeIOException;
import org.apache.james.mime4j.parser.AbstractContentHandler;
import org.apache.james.mime4j.parser.Field;
import org.apache.james.mime4j.parser.MimeStreamParser;
/**
* The header of an entity (see RFC 2045).
*/
public class Header implements Iterable<Field> {
private List<Field> fields = new LinkedList<Field>();
private Map<String, List<Field>> fieldMap = new HashMap<String, List<Field>>();
/**
* Creates a new empty <code>Header</code>.
*/
public Header() {
}
/**
* Creates a new <code>Header</code> from the specified
* <code>Header</code>. The <code>Header</code> instance is initialized
* with a copy of the list of {@link Field}s of the specified
* <code>Header</code>. The <code>Field</code> objects are not copied
* because they are immutable and can safely be shared between headers.
*
* @param other
* header to copy.
*/
public Header(Header other) {
for (Field otherField : other.fields) {
addField(otherField);
}
}
/**
* Creates a new <code>Header</code> from the specified stream.
*
* @param is the stream to read the header from.
*
* @throws IOException on I/O errors.
* @throws MimeIOException on MIME protocol violations.
*/
public Header(InputStream is)
throws IOException, MimeIOException {
final MimeStreamParser parser = new MimeStreamParser();
parser.setContentHandler(new AbstractContentHandler() {
@Override
public void endHeader() {
parser.stop();
}
@Override
public void field(Field field) throws MimeException {
addField(field);
}
});
try {
parser.parse(is);
} catch (MimeException ex) {
throw new MimeIOException(ex);
}
}
/**
* Adds a field to the end of the list of fields.
*
* @param field the field to add.
*/
public void addField(Field field) {
List<Field> values = fieldMap.get(field.getName().toLowerCase());
if (values == null) {
values = new LinkedList<Field>();
fieldMap.put(field.getName().toLowerCase(), values);
}
values.add(field);
fields.add(field);
}
/**
* Gets the fields of this header. The returned list will not be
* modifiable.
*
* @return the list of <code>Field</code> objects.
*/
public List<Field> getFields() {
return Collections.unmodifiableList(fields);
}
/**
* Gets a <code>Field</code> given a field name. If there are multiple
* such fields defined in this header the first one will be returned.
*
* @param name the field name (e.g. From, Subject).
* @return the field or <code>null</code> if none found.
*/
public Field getField(String name) {
List<Field> l = fieldMap.get(name.toLowerCase());
if (l != null && !l.isEmpty()) {
return l.get(0);
}
return null;
}
/**
* Gets all <code>Field</code>s having the specified field name.
*
* @param name the field name (e.g. From, Subject).
* @return the list of fields.
*/
public List<Field> getFields(final String name) {
final String lowerCaseName = name.toLowerCase();
final List<Field> l = fieldMap.get(lowerCaseName);
final List<Field> results;
if (l == null || l.isEmpty()) {
results = Collections.emptyList();
} else {
results = Collections.unmodifiableList(l);
}
return results;
}
/**
* Returns an iterator over the list of fields of this header.
*
* @return an iterator.
*/
public Iterator<Field> iterator() {
return Collections.unmodifiableList(fields).iterator();
}
/**
* Removes all <code>Field</code>s having the specified field name.
*
* @param name
* the field name (e.g. From, Subject).
* @return number of fields removed.
*/
public int removeFields(String name) {
final String lowerCaseName = name.toLowerCase();
List<Field> removed = fieldMap.remove(lowerCaseName);
if (removed == null || removed.isEmpty())
return 0;
for (Iterator<Field> iterator = fields.iterator(); iterator.hasNext();) {
Field field = iterator.next();
if (field.getName().equalsIgnoreCase(name))
iterator.remove();
}
return removed.size();
}
/**
* Sets or replaces a field. This method is useful for header fields such as
* Subject or Message-ID that should not occur more than once in a message.
*
* If this <code>Header</code> does not already contain a header field of
* the same name as the given field then it is added to the end of the list
* of fields (same behavior as {@link #addField(Field)}). Otherwise the
* first occurrence of a field with the same name is replaced by the given
* field and all further occurrences are removed.
*
* @param field the field to set.
*/
public void setField(Field field) {
final String lowerCaseName = field.getName().toLowerCase();
List<Field> l = fieldMap.get(lowerCaseName);
if (l == null || l.isEmpty()) {
addField(field);
return;
}
l.clear();
l.add(field);
int firstOccurrence = -1;
int index = 0;
for (Iterator<Field> iterator = fields.iterator(); iterator.hasNext(); index++) {
Field f = iterator.next();
if (f.getName().equalsIgnoreCase(field.getName())) {
iterator.remove();
if (firstOccurrence == -1)
firstOccurrence = index;
}
}
fields.add(firstOccurrence, field);
}
/**
* Return Header Object as String representation. Each headerline is
* seperated by "\r\n"
*
* @return headers
*/
@Override
public String toString() {
StringBuilder str = new StringBuilder(128);
for (Field field : fields) {
str.append(field.toString());
str.append("\r\n");
}
return str.toString();
}
}