java/10 : java.xml.ws/com/sun/xml/internal/ws/api/message/Header.java

Header
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package com.sun.xml.internal.ws.api.message;

import com.sun.istack.internal.NotNull;
import com.sun.istack.internal.Nullable;
import com.sun.xml.internal.bind.api.Bridge;
import com.sun.xml.internal.ws.api.SOAPVersion;
import com.sun.xml.internal.ws.api.addressing.AddressingVersion;
import com.sun.xml.internal.ws.api.addressing.WSEndpointReference;
import com.sun.xml.internal.ws.spi.db.XMLBridge;

import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.namespace.QName;
import javax.xml.soap.SOAPException;
import javax.xml.soap.SOAPMessage;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.ws.WebServiceException;
import java.util.Set;


A SOAP header.
 A header is immutable, but unlike body it can be read multiple times. The Header abstraction hides how the header data is represented in memory; instead, it commits to the ability to write itself to XML infoset. 
 When a message is received from the transport and being processed, the processor needs to "peek" some information of a header, such as the tag name, the mustUnderstand attribute, and so on. Therefore, the Header interface exposes those information as properties, so that they can be checked without replaying the infoset, which is efficiently but still costly. 
 A Header may belong to more than one HeaderList due to wrapping of Message. 
See Also: HeaderList
Headers/**
 * A SOAP header.
 *
 * <p>
 * A header is immutable, but unlike body it can be read
 * multiple times.
 * The {@link Header} abstraction hides how the header
 * data is represented in memory; instead, it commits to
 * the ability to write itself to XML infoset.
 *
 * <p>
 * When a message is received from the transport and
 * being processed, the processor needs to "peek"
 * some information of a header, such as the tag name,
 * the mustUnderstand attribute, and so on. Therefore,
 * the {@link Header} interface exposes those information
 * as properties, so that they can be checked without
 * replaying the infoset, which is efficiently but still
 * costly.
 *
 * <p>
 * A {@link Header} may belong to more than one {@link HeaderList}
 * due to wrapping of {@link Message}.
 *
 * @see HeaderList
 * @see Headers
 */
public interface Header {
    // TODO: Vivek pointed out that the only time we are looking at
    // mustUnderstand and role are when we do the mustUnderstand error check
    // (that is, to find out if there's any header with @mustUnderstand that
    // has appropriate role for us.)
    // if that's the case, it might be better if we define this whole operation
    // as one method, instead of exposing two properties.

    Checks if this header is ignorable for us (IOW, make sure
that this header has a problematic "mustUnderstand" header value
that we have to reject.)

This method is used as a part of the
mustUnderstanx processing. At the end of the processing, the JAX-WS identifies a list of Headers that were not understood. This method is invoked on those Headers, to verify that we don't need to report an error for it. 

specifically, this method has to perform the following tasks:

 If this header does not have mustUnderstand as "1" nor "true", then this method must return true. 
Otherwise, check the role attribute (for SOAP 1.2) or the actor attribute (for SOAP 1.1). When those attributes are absent, the default values have to be assumed. See getRole(SOAPVersion) for how the values are defaulted. Now, see if the roles set contains the value. If so, this method must return false (indicating that an error is in order.) 
Otherwise return true (since we don't play the role this header is intended for.)

Params: soapVersion –  The caller specifies the SOAP version that the pipeline is working against. Often each Header implementation already knows the SOAP version anyway, but this allows some Headers to avoid keeping it. That's why this redundant parameter is passed in.
roles – 
     The set of role values that the current JAX-WS pipeline is assuming.
     Note that SOAP 1.1 and SOAP 1.2 use different strings for the same role,
     and the caller is responsible for supplying a proper value depending on the
     active SOAP version in use.
Returns: 
     true if no error needs to be reported. False if an error needs to be raised.
     See the method javadoc for more discussion./**
     * Checks if this header is ignorable for us (IOW, make sure
     * that this header has a problematic "mustUnderstand" header value
     * that we have to reject.)
     *
     * <p>
     * This method is used as a part of the
     * <a href="HeaderList.html#MU">mustUnderstanx processing</a>.
     * At the end of the processing, the JAX-WS identifies a list of {@link Header}s
     * that were not understood. This method is invoked on those {@link Header}s,
     * to verify that we don't need to report an error for it.
     *
     * <p>
     * specifically, this method has to perform the following tasks:
     *
     * <ul>
     *  <li>If this header does not have {@code mustUnderstand} as "1" nor "true",
     *      then this method must return true.
     *  <li>Otherwise, check the role attribute (for SOAP 1.2) or the actor attribute (for SOAP 1.1).
     *      When those attributes are absent, the default values have to be assumed.
     *      See {@link #getRole(SOAPVersion)} for how the values are defaulted.
     *      Now, see if the {@code roles} set contains the value.
     *      If so, this method must return false (indicating that an error is in order.)
     *  <li>Otherwise return true (since we don't play the role this header is intended for.)
     * </ul>
     *
     * @param soapVersion
     *      The caller specifies the SOAP version that the pipeline is working against.
     *      Often each {@link Header} implementation already knows the SOAP version
     *      anyway, but this allows some {@link Header}s to avoid keeping it.
     *      That's why this redundant parameter is passed in.
     * @param roles
     *      The set of role values that the current JAX-WS pipeline is assuming.
     *      Note that SOAP 1.1 and SOAP 1.2 use different strings for the same role,
     *      and the caller is responsible for supplying a proper value depending on the
     *      active SOAP version in use.
     *
     * @return
     *      true if no error needs to be reported. False if an error needs to be raised.
     *      See the method javadoc for more discussion.
     */
    public boolean isIgnorable(@NotNull SOAPVersion soapVersion, @NotNull Set<String> roles);

    Gets the value of the soap:role attribute (or soap:actor for SOAP 1.1).
 If the attribute is omitted, the value defaults to SOAPVersion.implicitRole. 
Params: soapVersion –  The caller specifies the SOAP version that the pipeline is working against. Often each Header implementation already knows the SOAP version anyway, but this allows some Headers to avoid keeping it. That's why this redundant parameter is passed in.
Returns: 
     never null. This string need not be interned./**
     * Gets the value of the soap:role attribute (or soap:actor for SOAP 1.1).
     *
     * <p>
     * If the attribute is omitted, the value defaults to {@link SOAPVersion#implicitRole}.
     *
     * @param soapVersion
     *      The caller specifies the SOAP version that the pipeline is working against.
     *      Often each {@link Header} implementation already knows the SOAP version
     *      anyway, but this allows some {@link Header}s to avoid keeping it.
     *      That's why this redundant parameter is passed in.
     * @return
     *      never null. This string need not be interned.
     */
    public @NotNull String getRole(@NotNull SOAPVersion soapVersion);

    True if this header is to be relayed if not processed.
For SOAP 1.1 messages, this method always return false.

IOW, this method returns true if there's @soap:relay='true'
is present.
Implementation Note

The implementation needs to check for both "true" and "1",
but because attribute values are normalized, it doesn't have
to consider " true", " 1 ", and so on.
Returns: 
     false./**
     * True if this header is to be relayed if not processed.
     * For SOAP 1.1 messages, this method always return false.
     *
     * <p>
     * IOW, this method returns true if there's @soap:relay='true'
     * is present.
     *
     * <h3>Implementation Note</h3>
     * <p>
     * The implementation needs to check for both "true" and "1",
     * but because attribute values are normalized, it doesn't have
     * to consider " true", " 1 ", and so on.
     *
     * @return
     *      false.
     */
    public boolean isRelay();

    Gets the namespace URI of this header element.
Returns: 
     this string must be interned./**
     * Gets the namespace URI of this header element.
     *
     * @return
     *      this string must be interned.
     */
    public @NotNull String getNamespaceURI();

    Gets the local name of this header element.
Returns: 
     this string must be interned./**
     * Gets the local name of this header element.
     *
     * @return
     *      this string must be interned.
     */
    public @NotNull String getLocalPart();

    Gets the attribute value on the header element.
Params: nsUri – 
     The namespace URI of the attribute. Can be empty.
localName – 
     The local name of the attribute.
Returns:  if the attribute is found, return the whitespace normalized value. (meaning no leading/trailing space, no consequtive whitespaces in-between.) Otherwise null. Note that the XML parsers are responsible for whitespace-normalizing attributes, so Header implementation doesn't have to do anything./**
     * Gets the attribute value on the header element.
     *
     * @param nsUri
     *      The namespace URI of the attribute. Can be empty.
     * @param localName
     *      The local name of the attribute.
     *
     * @return
     *      if the attribute is found, return the whitespace normalized value.
     *      (meaning no leading/trailing space, no consequtive whitespaces in-between.)
     *      Otherwise null. Note that the XML parsers are responsible for
     *      whitespace-normalizing attributes, so {@link Header} implementation
     *      doesn't have to do anything.
     */
    @Nullable String getAttribute(@NotNull String nsUri, @NotNull String localName);

    Gets the attribute value on the header element.
 This is a convenience method that calls into getAttribute(String, String) 
Params: name – 
     Never null.
See Also: getAttribute(String, String)/**
     * Gets the attribute value on the header element.
     *
     * <p>
     * This is a convenience method that calls into {@link #getAttribute(String, String)}
     *
     * @param name
     *      Never null.
     *
     * @see #getAttribute(String, String)
     */
    @Nullable String getAttribute(@NotNull QName name);

    Reads the header as a XMLStreamReader.  The returned parser points at the start element of this header. (IOW, XMLStreamReader.getEventType() would return XMLStreamConstants.START_ELEMENT. 
Performance Expectation
 For some Header implementations, this operation is a non-trivial operation. Therefore, use of this method is discouraged unless the caller is interested in reading the whole header. 
 Similarly, if the caller wants to use this method only to do the API conversion (such as simply firing SAX events from XMLStreamReader), then the JAX-WS team requests that you talk to us. 
 Messages that come from tranport usually provides a reasonably efficient implementation of this method. 
Returns: 
     must not null./**
     * Reads the header as a {@link XMLStreamReader}.
     *
     * <p>
     * The returned parser points at the start element of this header.
     * (IOW, {@link XMLStreamReader#getEventType()} would return
     * {@link XMLStreamReader#START_ELEMENT}.
     *
     * <h3>Performance Expectation</h3>
     * <p>
     * For some {@link Header} implementations, this operation
     * is a non-trivial operation. Therefore, use of this method
     * is discouraged unless the caller is interested in reading
     * the whole header.
     *
     * <p>
     * Similarly, if the caller wants to use this method only to do
     * the API conversion (such as simply firing SAX events from
     * {@link XMLStreamReader}), then the JAX-WS team requests
     * that you talk to us.
     *
     * <p>
     * {@link Message}s that come from tranport usually provides
     * a reasonably efficient implementation of this method.
     *
     * @return
     *      must not null.
     */
    public XMLStreamReader readHeader() throws XMLStreamException;

    Reads the header as a JAXB object by using the given unmarshaller.
/**
     * Reads the header as a JAXB object by using the given unmarshaller.
     */
    public <T> T readAsJAXB(Unmarshaller unmarshaller) throws JAXBException;

    Reads the header as a JAXB object by using the given unmarshaller.
Deprecated: /**
     * Reads the header as a JAXB object by using the given unmarshaller.
     * @deprecated
     */
    public <T> T readAsJAXB(Bridge<T> bridge) throws JAXBException;

    Reads the header as a data-bond object
/**
     * Reads the header as a data-bond object
     */
    public <T> T readAsJAXB(XMLBridge<T> bridge) throws JAXBException;

    Reads this header as an WSEndpointReference. 
Params: expected –  The version of the addressing used to parse the EPR. If the actual infoset and this doesn't agree, then you'll get an WebServiceException stating that fact.
Returns: 
     On a successful return, this method never returns null./**
     * Reads this header as an {@link WSEndpointReference}.
     *
     * @param expected
     *      The version of the addressing used to parse the EPR.
     *      If the actual infoset and this doesn't agree, then
     *      you'll get an {@link WebServiceException} stating that fact.
     *
     * @return
     *      On a successful return, this method never returns null.
     */
    public @NotNull WSEndpointReference readAsEPR(AddressingVersion expected) throws XMLStreamException;

    Writes out the header as a fragment.
Throws: XMLStreamException – 
     if the operation fails for some reason. This leaves the
     writer to an undefined state./**
     * Writes out the header as a fragment.
     *
     * @throws XMLStreamException
     *      if the operation fails for some reason. This leaves the
     *      writer to an undefined state.
     */
    public void writeTo(XMLStreamWriter w) throws XMLStreamException;

    Writes out the header to the given SOAPMessage.
 Sometimes a Message needs to produce itself as SOAPMessage, in which case each header needs to turn itself into a header. 
Throws: SOAPException – 
     if the operation fails for some reason. This leaves the
     writer to an undefined state./**
     * Writes out the header to the given SOAPMessage.
     *
     * <p>
     * Sometimes a {@link Message} needs to produce itself
     * as {@link SOAPMessage}, in which case each header needs
     * to turn itself into a header.
     *
     * @throws SOAPException
     *      if the operation fails for some reason. This leaves the
     *      writer to an undefined state.
     */
    public void writeTo(SOAPMessage saaj) throws SOAPException;

    Writes out the header as SAX events.
 Sometimes a Message needs to produce SAX events, and this method is necessary for headers to participate to it. 
 A header is responsible for producing the SAX events for its part, including startPrefixMapping and endPrefixMapping, but not startDocument/endDocument. 
 Note that SAX contract requires that any error that does NOT originate from ContentHandler (meaning any parsing error and etc) must be first reported to ErrorHandler. If the SAX event production cannot be continued and the processing needs to abort, the code may then throw the same SAXParseException reported to ErrorHandler. 
Params: contentHandler –  The ContentHandler that receives SAX events.
errorHandler –  The ErrorHandler that receives parsing errors./**
     * Writes out the header as SAX events.
     *
     * <p>
     * Sometimes a {@link Message} needs to produce SAX events,
     * and this method is necessary for headers to participate to it.
     *
     * <p>
     * A header is responsible for producing the SAX events for its part,
     * including {@code startPrefixMapping} and {@code endPrefixMapping},
     * but not startDocument/endDocument.
     *
     * <p>
     * Note that SAX contract requires that any error that does NOT originate
     * from {@link ContentHandler} (meaning any parsing error and etc) must
     * be first reported to {@link ErrorHandler}. If the SAX event production
     * cannot be continued and the processing needs to abort, the code may
     * then throw the same {@link SAXParseException} reported to {@link ErrorHandler}.
     *
     * @param contentHandler
     *      The {@link ContentHandler} that receives SAX events.
     *
     * @param errorHandler
     *      The {@link ErrorHandler} that receives parsing errors.
     */
    public void writeTo(ContentHandler contentHandler, ErrorHandler errorHandler) throws SAXException;

    Used to obtain value XYZ from a header that looks like
"<header>XYZ</header>". The primary use of this header
for now is to access certain Addressing headers quickly.
Throws: WebServiceException – 
     If the structure of the header is more complicated than
     a simple string header.
Returns: 
     Can be empty but always non-null./**
     * Used to obtain value XYZ from a header that looks like
     * "&lt;header&gt;XYZ&lt;/header&gt;". The primary use of this header
     * for now is to access certain Addressing headers quickly.
     *
     * @throws WebServiceException
     *      If the structure of the header is more complicated than
     *      a simple string header.
     *
     * @return
     *      Can be empty but always non-null.
     */
    public @NotNull String getStringContent();
}
Params:	soapVersion – The caller specifies the SOAP version that the pipeline is working against. Often each `Header` implementation already knows the SOAP version anyway, but this allows some `Header`s to avoid keeping it. That's why this redundant parameter is passed in.
Returns:	never null. This string need not be interned.
Params:	nsUri – The namespace URI of the attribute. Can be empty. localName – The local name of the attribute.
Returns:	if the attribute is found, return the whitespace normalized value. (meaning no leading/trailing space, no consequtive whitespaces in-between.) Otherwise null. Note that the XML parsers are responsible for whitespace-normalizing attributes, so `Header` implementation doesn't have to do anything.
Params:	name – Never null.
See Also:	getAttribute(String, String)
Params:	expected – The version of the addressing used to parse the EPR. If the actual infoset and this doesn't agree, then you'll get an `WebServiceException` stating that fact.
Returns:	On a successful return, this method never returns null.
Throws:	WebServiceException – If the structure of the header is more complicated than a simple string header.
Returns:	Can be empty but always non-null.
/

java/ 10/ java.xml.ws/com/sun/xml/internal/ws/api/message/Header.java

Implementation Note

Performance Expectation
