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Diffstat (limited to 'libjava/org/xml/sax/helpers/NamespaceSupport.java')
| -rw-r--r-- | libjava/org/xml/sax/helpers/NamespaceSupport.java | 689 |
1 files changed, 689 insertions, 0 deletions
diff --git a/libjava/org/xml/sax/helpers/NamespaceSupport.java b/libjava/org/xml/sax/helpers/NamespaceSupport.java new file mode 100644 index 00000000000..a4588c3d2c7 --- /dev/null +++ b/libjava/org/xml/sax/helpers/NamespaceSupport.java @@ -0,0 +1,689 @@ +// NamespaceSupport.java - generic Namespace support for SAX.
+// Written by David Megginson, sax@megginson.com
+// This class is in the Public Domain. NO WARRANTY!
+
+// $Id: NamespaceSupport.java,v 1.1 2000/10/02 02:43:20 sboag Exp $
+
+package org.xml.sax.helpers;
+
+import java.util.EmptyStackException;
+import java.util.Enumeration;
+import java.util.Hashtable;
+import java.util.Vector;
+
+
+/**
+ * Encapsulate Namespace logic for use by SAX drivers.
+ *
+ * <blockquote>
+ * <em>This module, both source code and documentation, is in the
+ * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
+ * </blockquote>
+ *
+ * <p>This class encapsulates the logic of Namespace processing:
+ * it tracks the declarations currently in force for each context
+ * and automatically processes qualified XML 1.0 names into their
+ * Namespace parts; it can also be used in reverse for generating
+ * XML 1.0 from Namespaces.</p>
+ *
+ * <p>Namespace support objects are reusable, but the reset method
+ * must be invoked between each session.</p>
+ *
+ * <p>Here is a simple session:</p>
+ *
+ * <pre>
+ * String parts[] = new String[3];
+ * NamespaceSupport support = new NamespaceSupport();
+ *
+ * support.pushContext();
+ * support.declarePrefix("", "http://www.w3.org/1999/xhtml");
+ * support.declarePrefix("dc", "http://www.purl.org/dc#");
+ *
+ * String parts[] = support.processName("p", parts, false);
+ * System.out.println("Namespace URI: " + parts[0]);
+ * System.out.println("Local name: " + parts[1]);
+ * System.out.println("Raw name: " + parts[2]);
+
+ * String parts[] = support.processName("dc:title", parts, false);
+ * System.out.println("Namespace URI: " + parts[0]);
+ * System.out.println("Local name: " + parts[1]);
+ * System.out.println("Raw name: " + parts[2]);
+
+ * support.popContext();
+ * </pre>
+ *
+ * <p>Note that this class is optimized for the use case where most
+ * elements do not contain Namespace declarations: if the same
+ * prefix/URI mapping is repeated for each context (for example), this
+ * class will be somewhat less efficient.</p>
+ *
+ * @since SAX 2.0
+ * @author David Megginson,
+ * <a href="mailto:sax@megginson.com">sax@megginson.com</a>
+ * @version 2.0
+ */
+public class NamespaceSupport
+{
+
+
+ ////////////////////////////////////////////////////////////////////
+ // Constants.
+ ////////////////////////////////////////////////////////////////////
+
+
+ /**
+ * The XML Namespace as a constant.
+ *
+ * <p>This is the Namespace URI that is automatically mapped
+ * to the "xml" prefix.</p>
+ */
+ public final static String XMLNS =
+ "http://www.w3.org/XML/1998/namespace";
+
+
+ /**
+ * An empty enumeration.
+ */
+ private final static Enumeration EMPTY_ENUMERATION =
+ new Vector().elements();
+
+
+ ////////////////////////////////////////////////////////////////////
+ // Constructor.
+ ////////////////////////////////////////////////////////////////////
+
+
+ /**
+ * Create a new Namespace support object.
+ */
+ public NamespaceSupport ()
+ {
+ reset();
+ }
+
+
+
+ ////////////////////////////////////////////////////////////////////
+ // Context management.
+ ////////////////////////////////////////////////////////////////////
+
+
+ /**
+ * Reset this Namespace support object for reuse.
+ *
+ * <p>It is necessary to invoke this method before reusing the
+ * Namespace support object for a new session.</p>
+ */
+ public void reset ()
+ {
+ contexts = new Context[32];
+ contextPos = 0;
+ contexts[contextPos] = currentContext = new Context();
+ currentContext.declarePrefix("xml", XMLNS);
+ }
+
+
+ /**
+ * Start a new Namespace context.
+ *
+ * <p>Normally, you should push a new context at the beginning
+ * of each XML element: the new context will automatically inherit
+ * the declarations of its parent context, but it will also keep
+ * track of which declarations were made within this context.</p>
+ *
+ * <p>The Namespace support object always starts with a base context
+ * already in force: in this context, only the "xml" prefix is
+ * declared.</p>
+ *
+ * @see #popContext
+ */
+ public void pushContext ()
+ {
+ int max = contexts.length;
+ contextPos++;
+
+ // Extend the array if necessary
+ if (contextPos >= max) {
+ Context newContexts[] = new Context[max*2];
+ System.arraycopy(contexts, 0, newContexts, 0, max);
+ max *= 2;
+ contexts = newContexts;
+ }
+
+ // Allocate the context if necessary.
+ currentContext = contexts[contextPos];
+ if (currentContext == null) {
+ contexts[contextPos] = currentContext = new Context();
+ }
+
+ // Set the parent, if any.
+ if (contextPos > 0) {
+ currentContext.setParent(contexts[contextPos - 1]);
+ }
+ }
+
+
+ /**
+ * Revert to the previous Namespace context.
+ *
+ * <p>Normally, you should pop the context at the end of each
+ * XML element. After popping the context, all Namespace prefix
+ * mappings that were previously in force are restored.</p>
+ *
+ * <p>You must not attempt to declare additional Namespace
+ * prefixes after popping a context, unless you push another
+ * context first.</p>
+ *
+ * @see #pushContext
+ */
+ public void popContext ()
+ {
+ contextPos--;
+ if (contextPos < 0) {
+ throw new EmptyStackException();
+ }
+ currentContext = contexts[contextPos];
+ }
+
+
+
+ ////////////////////////////////////////////////////////////////////
+ // Operations within a context.
+ ////////////////////////////////////////////////////////////////////
+
+
+ /**
+ * Declare a Namespace prefix.
+ *
+ * <p>This method declares a prefix in the current Namespace
+ * context; the prefix will remain in force until this context
+ * is popped, unless it is shadowed in a descendant context.</p>
+ *
+ * <p>To declare a default Namespace, use the empty string. The
+ * prefix must not be "xml" or "xmlns".</p>
+ *
+ * <p>Note that you must <em>not</em> declare a prefix after
+ * you've pushed and popped another Namespace.</p>
+ *
+ * <p>Note that there is an asymmetry in this library: while {@link
+ * #getPrefix getPrefix} will not return the default "" prefix,
+ * even if you have declared one; to check for a default prefix,
+ * you have to look it up explicitly using {@link #getURI getURI}.
+ * This asymmetry exists to make it easier to look up prefixes
+ * for attribute names, where the default prefix is not allowed.</p>
+ *
+ * @param prefix The prefix to declare, or null for the empty
+ * string.
+ * @param uri The Namespace URI to associate with the prefix.
+ * @return true if the prefix was legal, false otherwise
+ * @see #processName
+ * @see #getURI
+ * @see #getPrefix
+ */
+ public boolean declarePrefix (String prefix, String uri)
+ {
+ if (prefix.equals("xml") || prefix.equals("xmlns")) {
+ return false;
+ } else {
+ currentContext.declarePrefix(prefix, uri);
+ return true;
+ }
+ }
+
+
+ /**
+ * Process a raw XML 1.0 name.
+ *
+ * <p>This method processes a raw XML 1.0 name in the current
+ * context by removing the prefix and looking it up among the
+ * prefixes currently declared. The return value will be the
+ * array supplied by the caller, filled in as follows:</p>
+ *
+ * <dl>
+ * <dt>parts[0]</dt>
+ * <dd>The Namespace URI, or an empty string if none is
+ * in use.</dd>
+ * <dt>parts[1]</dt>
+ * <dd>The local name (without prefix).</dd>
+ * <dt>parts[2]</dt>
+ * <dd>The original raw name.</dd>
+ * </dl>
+ *
+ * <p>All of the strings in the array will be internalized. If
+ * the raw name has a prefix that has not been declared, then
+ * the return value will be null.</p>
+ *
+ * <p>Note that attribute names are processed differently than
+ * element names: an unprefixed element name will received the
+ * default Namespace (if any), while an unprefixed element name
+ * will not.</p>
+ *
+ * @param qName The raw XML 1.0 name to be processed.
+ * @param parts An array supplied by the caller, capable of
+ * holding at least three members.
+ * @param isAttribute A flag indicating whether this is an
+ * attribute name (true) or an element name (false).
+ * @return The supplied array holding three internalized strings
+ * representing the Namespace URI (or empty string), the
+ * local name, and the raw XML 1.0 name; or null if there
+ * is an undeclared prefix.
+ * @see #declarePrefix
+ * @see java.lang.String#intern */
+ public String [] processName (String qName, String parts[],
+ boolean isAttribute)
+ {
+ String myParts[] = currentContext.processName(qName, isAttribute);
+ if (myParts == null) {
+ return null;
+ } else {
+ parts[0] = myParts[0];
+ parts[1] = myParts[1];
+ parts[2] = myParts[2];
+ return parts;
+ }
+ }
+
+
+ /**
+ * Look up a prefix and get the currently-mapped Namespace URI.
+ *
+ * <p>This method looks up the prefix in the current context.
+ * Use the empty string ("") for the default Namespace.</p>
+ *
+ * @param prefix The prefix to look up.
+ * @return The associated Namespace URI, or null if the prefix
+ * is undeclared in this context.
+ * @see #getPrefix
+ * @see #getPrefixes
+ */
+ public String getURI (String prefix)
+ {
+ return currentContext.getURI(prefix);
+ }
+
+
+ /**
+ * Return an enumeration of all prefixes currently declared.
+ *
+ * <p><strong>Note:</strong> if there is a default prefix, it will not be
+ * returned in this enumeration; check for the default prefix
+ * using the {@link #getURI getURI} with an argument of "".</p>
+ *
+ * @return An enumeration of all prefixes declared in the
+ * current context except for the empty (default)
+ * prefix.
+ * @see #getDeclaredPrefixes
+ * @see #getURI
+ */
+ public Enumeration getPrefixes ()
+ {
+ return currentContext.getPrefixes();
+ }
+
+
+ /**
+ * Return one of the prefixes mapped to a Namespace URI.
+ *
+ * <p>If more than one prefix is currently mapped to the same
+ * URI, this method will make an arbitrary selection; if you
+ * want all of the prefixes, use the {@link #getPrefixes}
+ * method instead.</p>
+ *
+ * <p><strong>Note:</strong> this will never return the empty (default) prefix;
+ * to check for a default prefix, use the {@link #getURI getURI}
+ * method with an argument of "".</p>
+ *
+ * @param uri The Namespace URI.
+ * @param isAttribute true if this prefix is for an attribute
+ * (and the default Namespace is not allowed).
+ * @return One of the prefixes currently mapped to the URI supplied,
+ * or null if none is mapped or if the URI is assigned to
+ * the default Namespace.
+ * @see #getPrefixes(java.lang.String)
+ * @see #getURI
+ */
+ public String getPrefix (String uri)
+ {
+ return currentContext.getPrefix(uri);
+ }
+
+
+ /**
+ * Return an enumeration of all prefixes currently declared for a URI.
+ *
+ * <p>This method returns prefixes mapped to a specific Namespace
+ * URI. The xml: prefix will be included. If you want only one
+ * prefix that's mapped to the Namespace URI, and you don't care
+ * which one you get, use the {@link #getPrefix getPrefix}
+ * method instead.</p>
+ *
+ * <p><strong>Note:</strong> the empty (default) prefix is <em>never</em> included
+ * in this enumeration; to check for the presence of a default
+ * Namespace, use the {@link #getURI getURI} method with an
+ * argument of "".</p>
+ *
+ * @param uri The Namespace URI.
+ * @return An enumeration of all prefixes declared in the
+ * current context.
+ * @see #getPrefix
+ * @see #getDeclaredPrefixes
+ * @see #getURI
+ */
+ public Enumeration getPrefixes (String uri)
+ {
+ Vector prefixes = new Vector();
+ Enumeration allPrefixes = getPrefixes();
+ while (allPrefixes.hasMoreElements()) {
+ String prefix = (String)allPrefixes.nextElement();
+ if (uri.equals(getURI(prefix))) {
+ prefixes.addElement(prefix);
+ }
+ }
+ return prefixes.elements();
+ }
+
+
+ /**
+ * Return an enumeration of all prefixes declared in this context.
+ *
+ * <p>The empty (default) prefix will be included in this
+ * enumeration; note that this behaviour differs from that of
+ * {@link #getPrefix} and {@link #getPrefixes}.</p>
+ *
+ * @return An enumeration of all prefixes declared in this
+ * context.
+ * @see #getPrefixes
+ * @see #getURI
+ */
+ public Enumeration getDeclaredPrefixes ()
+ {
+ return currentContext.getDeclaredPrefixes();
+ }
+
+
+
+ ////////////////////////////////////////////////////////////////////
+ // Internal state.
+ ////////////////////////////////////////////////////////////////////
+
+ private Context contexts[];
+ private Context currentContext;
+ private int contextPos;
+
+
+
+ ////////////////////////////////////////////////////////////////////
+ // Internal classes.
+ ////////////////////////////////////////////////////////////////////
+
+ /**
+ * Internal class for a single Namespace context.
+ *
+ * <p>This module caches and reuses Namespace contexts, so the number allocated
+ * will be equal to the element depth of the document, not to the total
+ * number of elements (i.e. 5-10 rather than tens of thousands).</p>
+ */
+ final class Context {
+
+ /**
+ * Create the root-level Namespace context.
+ */
+ Context ()
+ {
+ copyTables();
+ }
+
+
+ /**
+ * (Re)set the parent of this Namespace context.
+ *
+ * @param context The parent Namespace context object.
+ */
+ void setParent (Context parent)
+ {
+ this.parent = parent;
+ declarations = null;
+ prefixTable = parent.prefixTable;
+ uriTable = parent.uriTable;
+ elementNameTable = parent.elementNameTable;
+ attributeNameTable = parent.attributeNameTable;
+ defaultNS = parent.defaultNS;
+ tablesDirty = false;
+ }
+
+
+ /**
+ * Declare a Namespace prefix for this context.
+ *
+ * @param prefix The prefix to declare.
+ * @param uri The associated Namespace URI.
+ * @see org.xml.sax.helpers.NamespaceSupport#declarePrefix
+ */
+ void declarePrefix (String prefix, String uri)
+ {
+ // Lazy processing...
+ if (!tablesDirty) {
+ copyTables();
+ }
+ if (declarations == null) {
+ declarations = new Vector();
+ }
+
+ prefix = prefix.intern();
+ uri = uri.intern();
+ if ("".equals(prefix)) {
+ if ("".equals(uri)) {
+ defaultNS = null;
+ } else {
+ defaultNS = uri;
+ }
+ } else {
+ prefixTable.put(prefix, uri);
+ uriTable.put(uri, prefix); // may wipe out another prefix
+ }
+ declarations.addElement(prefix);
+ }
+
+
+ /**
+ * Process a raw XML 1.0 name in this context.
+ *
+ * @param qName The raw XML 1.0 name.
+ * @param isAttribute true if this is an attribute name.
+ * @return An array of three strings containing the
+ * URI part (or empty string), the local part,
+ * and the raw name, all internalized, or null
+ * if there is an undeclared prefix.
+ * @see org.xml.sax.helpers.NamespaceSupport#processName
+ */
+ String [] processName (String qName, boolean isAttribute)
+ {
+ String name[];
+ Hashtable table;
+
+ // Select the appropriate table.
+ if (isAttribute) {
+ table = elementNameTable;
+ } else {
+ table = attributeNameTable;
+ }
+
+ // Start by looking in the cache, and
+ // return immediately if the name
+ // is already known in this content
+ name = (String[])table.get(qName);
+ if (name != null) {
+ return name;
+ }
+
+ // We haven't seen this name in this
+ // context before.
+ name = new String[3];
+ int index = qName.indexOf(':');
+
+
+ // No prefix.
+ if (index == -1) {
+ if (isAttribute || defaultNS == null) {
+ name[0] = "";
+ } else {
+ name[0] = defaultNS;
+ }
+ name[1] = qName.intern();
+ name[2] = name[1];
+ }
+
+ // Prefix
+ else {
+ String prefix = qName.substring(0, index);
+ String local = qName.substring(index+1);
+ String uri;
+ if ("".equals(prefix)) {
+ uri = defaultNS;
+ } else {
+ uri = (String)prefixTable.get(prefix);
+ }
+ if (uri == null) {
+ return null;
+ }
+ name[0] = uri;
+ name[1] = local.intern();
+ name[2] = qName.intern();
+ }
+
+ // Save in the cache for future use.
+ table.put(name[2], name);
+ tablesDirty = true;
+ return name;
+ }
+
+
+ /**
+ * Look up the URI associated with a prefix in this context.
+ *
+ * @param prefix The prefix to look up.
+ * @return The associated Namespace URI, or null if none is
+ * declared.
+ * @see org.xml.sax.helpers.NamespaceSupport#getURI
+ */
+ String getURI (String prefix)
+ {
+ if ("".equals(prefix)) {
+ return defaultNS;
+ } else if (prefixTable == null) {
+ return null;
+ } else {
+ return (String)prefixTable.get(prefix);
+ }
+ }
+
+
+ /**
+ * Look up one of the prefixes associated with a URI in this context.
+ *
+ * <p>Since many prefixes may be mapped to the same URI,
+ * the return value may be unreliable.</p>
+ *
+ * @param uri The URI to look up.
+ * @return The associated prefix, or null if none is declared.
+ * @see org.xml.sax.helpers.NamespaceSupport#getPrefix
+ */
+ String getPrefix (String uri)
+ {
+ if (uriTable == null) {
+ return null;
+ } else {
+ return (String)uriTable.get(uri);
+ }
+ }
+
+
+ /**
+ * Return an enumeration of prefixes declared in this context.
+ *
+ * @return An enumeration of prefixes (possibly empty).
+ * @see org.xml.sax.helpers.NamespaceSupport#getDeclaredPrefixes
+ */
+ Enumeration getDeclaredPrefixes ()
+ {
+ if (declarations == null) {
+ return EMPTY_ENUMERATION;
+ } else {
+ return declarations.elements();
+ }
+ }
+
+
+ /**
+ * Return an enumeration of all prefixes currently in force.
+ *
+ * <p>The default prefix, if in force, is <em>not</em>
+ * returned, and will have to be checked for separately.</p>
+ *
+ * @return An enumeration of prefixes (never empty).
+ * @see org.xml.sax.helpers.NamespaceSupport#getPrefixes
+ */
+ Enumeration getPrefixes ()
+ {
+ if (prefixTable == null) {
+ return EMPTY_ENUMERATION;
+ } else {
+ return prefixTable.keys();
+ }
+ }
+
+
+
+ ////////////////////////////////////////////////////////////////
+ // Internal methods.
+ ////////////////////////////////////////////////////////////////
+
+
+ /**
+ * Copy on write for the internal tables in this context.
+ *
+ * <p>This class is optimized for the normal case where most
+ * elements do not contain Namespace declarations.</p>
+ */
+ private void copyTables ()
+ {
+ if (prefixTable != null) {
+ prefixTable = (Hashtable)prefixTable.clone();
+ } else {
+ prefixTable = new Hashtable();
+ }
+ if (uriTable != null) {
+ uriTable = (Hashtable)uriTable.clone();
+ } else {
+ uriTable = new Hashtable();
+ }
+ elementNameTable = new Hashtable();
+ attributeNameTable = new Hashtable();
+ tablesDirty = true;
+ }
+
+
+
+ ////////////////////////////////////////////////////////////////
+ // Protected state.
+ ////////////////////////////////////////////////////////////////
+
+ Hashtable prefixTable;
+ Hashtable uriTable;
+ Hashtable elementNameTable;
+ Hashtable attributeNameTable;
+ String defaultNS = null;
+
+
+
+ ////////////////////////////////////////////////////////////////
+ // Internal state.
+ ////////////////////////////////////////////////////////////////
+
+ private Vector declarations = null;
+ private boolean tablesDirty = false;
+ private Context parent = null;
+ }
+}
+
+// end of NamespaceSupport.java
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