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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * 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).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.jndi.toolkit.url;

import javax.naming.*;
import javax.naming.spi.ResolveResult;
import javax.naming.spi.NamingManager;

import java.util.Hashtable;
import java.net.MalformedURLException;

This abstract class is a generic URL context that accepts as the
name argument either a string URL or a Name whose first component
is a URL. It resolves the URL to a target context and then continues
the operation using the remaining name in the target context as if
the first component names a junction.
A subclass must define getRootURLContext()
to process the URL into head/tail pieces. If it wants to control how
URL strings are parsed and compared for the rename() operation, then
it should override getNonRootURLSuffixes() and urlEquals().
Author:
Scott Seligman, Rosanna Lee/**
 * This abstract class is a generic URL context that accepts as the
 * name argument either a string URL or a Name whose first component
 * is a URL. It resolves the URL to a target context and then continues
 * the operation using the remaining name in the target context as if
 * the first component names a junction.
 *
 * A subclass must define getRootURLContext()
 * to process the URL into head/tail pieces. If it wants to control how
 * URL strings are parsed and compared for the rename() operation, then
 * it should override getNonRootURLSuffixes() and urlEquals().
 *
 * @author Scott Seligman
 * @author Rosanna Lee
 */
abstract public class GenericURLContext implements Context {
    protected Hashtable myEnv = null;

    public GenericURLContext(Hashtable env) {
        // context that is not tied to any specific URL
        myEnv = env;  // copied on write
    }

    public void close() throws NamingException {
        myEnv = null;
    }

    public String getNameInNamespace() throws NamingException {
        return ""; // %%% check this out: A URL context's name is ""
    }

    
Resolves 'name' into a target context with remaining name.
For example, with a JNDI URL "jndi://dnsname/rest_name",
this method resolves "jndi://dnsname/" to a target context,
and returns the target context with "rest_name".
The definition of "root URL" and how much of the URL to
consume is implementation specific.
If rename() is supported for a particular URL scheme,
getRootURLContext(), getURLPrefix(), and getURLSuffix()
must be in sync wrt how URLs are parsed and returned.
/**
      * Resolves 'name' into a target context with remaining name.
      * For example, with a JNDI URL "jndi://dnsname/rest_name",
      * this method resolves "jndi://dnsname/" to a target context,
      * and returns the target context with "rest_name".
      * The definition of "root URL" and how much of the URL to
      * consume is implementation specific.
      * If rename() is supported for a particular URL scheme,
      * getRootURLContext(), getURLPrefix(), and getURLSuffix()
      * must be in sync wrt how URLs are parsed and returned.
      */
    abstract protected ResolveResult getRootURLContext(String url,
        Hashtable env) throws NamingException;

    
Returns the suffix of the url. The result should be identical to
that of calling getRootURLContext().getRemainingName(), but
without the overhead of doing anything with the prefix like
creating a context.

This method returns a Name instead of a String because to give
the provider an opportunity to return a Name (for example,
for weakly separated naming systems like COS naming).

The default implementation uses skips 'prefix', calls
UrlUtil.decode() on it, and returns the result as a single component
CompositeName.
Subclass should override if this is not appropriate.
This method is used only by rename().
If rename() is supported for a particular URL scheme,
getRootURLContext(), getURLPrefix(), and getURLSuffix()
must be in sync wrt how URLs are parsed and returned.

For many URL schemes, this method is very similar to URL.getFile(),
except getFile() will return a leading slash in the
2nd, 3rd, and 4th cases. For schemes like "ldap" and "iiop",
the leading slash must be skipped before the name is an acceptable
format for operation by the Context methods. For schemes that treat the
leading slash as significant (such as "file"),
the subclass must override getURLSuffix() to get the correct behavior.
Remember, the behavior must match getRootURLContext().
URL                                     Suffix
foo://host:port                         
foo://host:port/rest/of/name            rest/of/name
foo:///rest/of/name                     rest/of/name
foo:/rest/of/name                       rest/of/name
foo:rest/of/name                        rest/of/name
/**
      * Returns the suffix of the url. The result should be identical to
      * that of calling getRootURLContext().getRemainingName(), but
      * without the overhead of doing anything with the prefix like
      * creating a context.
      *<p>
      * This method returns a Name instead of a String because to give
      * the provider an opportunity to return a Name (for example,
      * for weakly separated naming systems like COS naming).
      *<p>
      * The default implementation uses skips 'prefix', calls
      * UrlUtil.decode() on it, and returns the result as a single component
      * CompositeName.
      * Subclass should override if this is not appropriate.
      * This method is used only by rename().
      * If rename() is supported for a particular URL scheme,
      * getRootURLContext(), getURLPrefix(), and getURLSuffix()
      * must be in sync wrt how URLs are parsed and returned.
      *<p>
      * For many URL schemes, this method is very similar to URL.getFile(),
      * except getFile() will return a leading slash in the
      * 2nd, 3rd, and 4th cases. For schemes like "ldap" and "iiop",
      * the leading slash must be skipped before the name is an acceptable
      * format for operation by the Context methods. For schemes that treat the
      * leading slash as significant (such as "file"),
      * the subclass must override getURLSuffix() to get the correct behavior.
      * Remember, the behavior must match getRootURLContext().
      *
      * URL                                     Suffix
      * foo://host:port                         <empty string>
      * foo://host:port/rest/of/name            rest/of/name
      * foo:///rest/of/name                     rest/of/name
      * foo:/rest/of/name                       rest/of/name
      * foo:rest/of/name                        rest/of/name
      */
    protected Name getURLSuffix(String prefix, String url) throws NamingException {
        String suffix = url.substring(prefix.length());
        if (suffix.length() == 0) {
            return new CompositeName();
        }

        if (suffix.charAt(0) == '/') {
            suffix = suffix.substring(1); // skip leading slash
        }

        try {
            return new CompositeName().add(UrlUtil.decode(suffix));
        } catch (MalformedURLException e) {
            throw new InvalidNameException(e.getMessage());
        }
    }

    
Finds the prefix of a URL.
Default implementation looks for slashes and then extracts
prefixes using String.substring().
Subclass should override if this is not appropriate.
This method is used only by rename().
If rename() is supported for a particular URL scheme,
getRootURLContext(), getURLPrefix(), and getURLSuffix()
must be in sync wrt how URLs are parsed and returned.

URL                                     Prefix
foo://host:port                         foo://host:port
foo://host:port/rest/of/name            foo://host:port
foo:///rest/of/name                     foo://
foo:/rest/of/name                       foo:
foo:rest/of/name                        foo:
/**
      * Finds the prefix of a URL.
      * Default implementation looks for slashes and then extracts
      * prefixes using String.substring().
      * Subclass should override if this is not appropriate.
      * This method is used only by rename().
      * If rename() is supported for a particular URL scheme,
      * getRootURLContext(), getURLPrefix(), and getURLSuffix()
      * must be in sync wrt how URLs are parsed and returned.
      *<p>
      * URL                                     Prefix
      * foo://host:port                         foo://host:port
      * foo://host:port/rest/of/name            foo://host:port
      * foo:///rest/of/name                     foo://
      * foo:/rest/of/name                       foo:
      * foo:rest/of/name                        foo:
      */
    protected String getURLPrefix(String url) throws NamingException {
        int start = url.indexOf(":");

        if (start < 0) {
            throw new OperationNotSupportedException("Invalid URL: " + url);
        }
        ++start; // skip ':'

        if (url.startsWith("//", start)) {
            start += 2;  // skip double slash

            // find last slash
            int posn = url.indexOf("/", start);
            if (posn >= 0) {
                start = posn;
            } else {
                start = url.length();  // rest of URL
            }
        }

        // else 0 or 1 iniitial slashes; start is unchanged
        return url.substring(0, start);
    }

    
Determines whether two URLs are the same.
Default implementation uses String.equals().
Subclass should override if this is not appropriate.
This method is used by rename().
/**
     * Determines whether two URLs are the same.
     * Default implementation uses String.equals().
     * Subclass should override if this is not appropriate.
     * This method is used by rename().
     */
    protected boolean urlEquals(String url1, String url2) {
        return url1.equals(url2);
    }

    
Gets the context in which to continue the operation. This method
is called when this context is asked to process a multicomponent
Name in which the first component is a URL.
Treat the first component like a junction: resolve it and then use
NamingManager.getContinuationContext() to get the target context in
which to operate on the remainder of the name (n.getSuffix(1)).
/**
     * Gets the context in which to continue the operation. This method
     * is called when this context is asked to process a multicomponent
     * Name in which the first component is a URL.
     * Treat the first component like a junction: resolve it and then use
     * NamingManager.getContinuationContext() to get the target context in
     * which to operate on the remainder of the name (n.getSuffix(1)).
     */
    protected Context getContinuationContext(Name n) throws NamingException {
        Object obj = lookup(n.get(0));
        CannotProceedException cpe = new CannotProceedException();
        cpe.setResolvedObj(obj);
        cpe.setEnvironment(myEnv);
        return NamingManager.getContinuationContext(cpe);
    }

    public Object lookup(String name) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            return ctx.lookup(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public Object lookup(Name name) throws NamingException {
        if (name.size() == 1) {
            return lookup(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                return ctx.lookup(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public void bind(String name, Object obj) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            ctx.bind(res.getRemainingName(), obj);
        } finally {
            ctx.close();
        }
    }

    public void bind(Name name, Object obj) throws NamingException {
        if (name.size() == 1) {
            bind(name.get(0), obj);
        } else {
            Context ctx = getContinuationContext(name);
            try {
                ctx.bind(name.getSuffix(1), obj);
            } finally {
                ctx.close();
            }
        }
    }

    public void rebind(String name, Object obj) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            ctx.rebind(res.getRemainingName(), obj);
        } finally {
            ctx.close();
        }
    }

    public void rebind(Name name, Object obj) throws NamingException {
        if (name.size() == 1) {
            rebind(name.get(0), obj);
        } else {
            Context ctx = getContinuationContext(name);
            try {
                ctx.rebind(name.getSuffix(1), obj);
            } finally {
                ctx.close();
            }
        }
    }

    public void unbind(String name) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            ctx.unbind(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public void unbind(Name name) throws NamingException {
        if (name.size() == 1) {
            unbind(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                ctx.unbind(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public void rename(String oldName, String newName) throws NamingException {
        String oldPrefix = getURLPrefix(oldName);
        String newPrefix = getURLPrefix(newName);
        if (!urlEquals(oldPrefix, newPrefix)) {
            throw new OperationNotSupportedException(
                "Renaming using different URL prefixes not supported : " +
                oldName + " " + newName);
        }

        ResolveResult res = getRootURLContext(oldName, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            ctx.rename(res.getRemainingName(), getURLSuffix(newPrefix, newName));
        } finally {
            ctx.close();
        }
    }

    public void rename(Name name, Name newName) throws NamingException {
        if (name.size() == 1) {
            if (newName.size() != 1) {
                throw new OperationNotSupportedException(
            "Renaming to a Name with more components not supported: " + newName);
            }
            rename(name.get(0), newName.get(0));
        } else {
            // > 1 component with 1st one being URL
            // URLs must be identical; cannot deal with diff URLs
            if (!urlEquals(name.get(0), newName.get(0))) {
                throw new OperationNotSupportedException(
                    "Renaming using different URLs as first components not supported: " +
                    name + " " + newName);
            }

            Context ctx = getContinuationContext(name);
            try {
                ctx.rename(name.getSuffix(1), newName.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public NamingEnumeration<NameClassPair> list(String name)   throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            return ctx.list(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public NamingEnumeration<NameClassPair> list(Name name) throws NamingException {
        if (name.size() == 1) {
            return list(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                return ctx.list(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public NamingEnumeration<Binding> listBindings(String name)
        throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            return ctx.listBindings(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public NamingEnumeration<Binding> listBindings(Name name) throws NamingException {
        if (name.size() == 1) {
            return listBindings(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                return ctx.listBindings(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public void destroySubcontext(String name) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            ctx.destroySubcontext(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public void destroySubcontext(Name name) throws NamingException {
        if (name.size() == 1) {
            destroySubcontext(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                ctx.destroySubcontext(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public Context createSubcontext(String name) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            return ctx.createSubcontext(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public Context createSubcontext(Name name) throws NamingException {
        if (name.size() == 1) {
            return createSubcontext(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                return ctx.createSubcontext(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public Object lookupLink(String name) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            return ctx.lookupLink(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public Object lookupLink(Name name) throws NamingException {
        if (name.size() == 1) {
            return lookupLink(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                return ctx.lookupLink(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public NameParser getNameParser(String name) throws NamingException {
        ResolveResult res = getRootURLContext(name, myEnv);
        Context ctx = (Context)res.getResolvedObj();
        try {
            return ctx.getNameParser(res.getRemainingName());
        } finally {
            ctx.close();
        }
    }

    public NameParser getNameParser(Name name) throws NamingException {
        if (name.size() == 1) {
            return getNameParser(name.get(0));
        } else {
            Context ctx = getContinuationContext(name);
            try {
                return ctx.getNameParser(name.getSuffix(1));
            } finally {
                ctx.close();
            }
        }
    }

    public String composeName(String name, String prefix)
        throws NamingException {
            if (prefix.equals("")) {
                return name;
            } else if (name.equals("")) {
                return prefix;
            } else {
                return (prefix + "/" + name);
            }
    }

    public Name composeName(Name name, Name prefix) throws NamingException {
        Name result = (Name)prefix.clone();
        result.addAll(name);
        return result;
    }

    public Object removeFromEnvironment(String propName)
        throws NamingException {
            if (myEnv == null) {
                return null;
            }
            myEnv = (Hashtable)myEnv.clone();
            return myEnv.remove(propName);
    }

    public Object addToEnvironment(String propName, Object propVal)
        throws NamingException {
            myEnv = (myEnv == null) ?
                new Hashtable(11, 0.75f) : (Hashtable)myEnv.clone();
            return myEnv.put(propName, propVal);
    }

    public Hashtable getEnvironment() throws NamingException {
        if (myEnv == null) {
            return new Hashtable(5, 0.75f);
        } else {
            return (Hashtable)myEnv.clone();
        }
    }

/*
// To test, declare getURLPrefix and getURLSuffix static.

    public static void main(String[] args) throws Exception {
        String[] tests = {"file://host:port",
                          "file:///rest/of/name",
                          "file://host:port/rest/of/name",
                          "file:/rest/of/name",
                          "file:rest/of/name"};
        for (int i = 0; i < tests.length; i++) {
            String pre = getURLPrefix(tests[i]);
            System.out.println(pre);
            System.out.println(getURLSuffix(pre, tests[i]));
        }
    }
*/
}