Created a form tool for generating form fields that automatically inherit

the values from the request parameters. Modified dispatcher servlet to put one in the context for every request. git-svn-id: https://samskivert.googlecode.com/svn/trunk@399 6335cc39-0255-0410-8fd6-9bcaacd3b74c
2001-10-31 11:07:55 +00:00
parent 39680c9e25
commit 879f0a5aaa
2 changed files with 183 additions and 1 deletions
@@ -1,5 +1,5 @@
 //
-// $Id: DispatcherServlet.java,v 1.2 2001/10/31 09:45:23 mdb Exp $
+// $Id: DispatcherServlet.java,v 1.3 2001/10/31 11:07:55 mdb Exp $
 //
 // samskivert library - useful routines for java programs
 // Copyright (C) 2001 Michael Bayne
@@ -232,6 +232,10 @@ public class DispatcherServlet extends VelocityServlet
                ictx.put(MSGRESOLVER_KEY, mrslv);
            }

+            // create a form tool for use by the template
+            FormTool form = new FormTool(req);
+            ictx.put(FORMTOOL_KEY, form);
+
            // resolve the appropriate logic class for this URI and
            // execute it if it exists
            String path = req.getServletPath();
@@ -367,6 +371,11 @@ public class DispatcherServlet extends VelocityServlet
     */
    protected static final String MSGRESOLVER_KEY = "i18n";

+    /**
+     * This is the key used to store the form tool in the context.
+     */
+    protected static final String FORMTOOL_KEY = "form";
+
    /** The servlet parameter key specifying the application class. */
    protected static final String APP_CLASS_PROPS_KEY = "app_class";

@@ -0,0 +1,173 @@
+//
+// $Id: FormTool.java,v 1.1 2001/10/31 11:07:55 mdb Exp $
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001 Michael Bayne
+// 
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library 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
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.velocity;
+
+import javax.servlet.http.HttpServletRequest;
+
+import com.samskivert.servlet.util.HTMLUtil;
+import com.samskivert.servlet.util.ParameterUtil;
+import com.samskivert.util.StringUtil;
+
+/**
+ * The form tool can be placed into an invocation context and used by the
+ * template to create form elements which automatically inherit form
+ * values which were provided to the page at request time.
+ *
+ * For example:
+ *
+ * <pre>
+ * Please enter your name: $form.text("name", 40) $form.submit("submit")
+ * </pre>
+ *
+ * If the servlet was invoked with a value for "name", it will be
+ * automatically filled into the "name" form field when it is requested.
+ */
+public class FormTool
+{
+    /**
+     * Constructs a form tool that will use the supplied HTTP servlet
+     * request object to prefetch form values.
+     */
+    public FormTool (HttpServletRequest req)
+    {
+        _req = req;
+    }
+
+    /**
+     * Creates a text input field with the specified name and no extra
+     * arguments or default value.
+     *
+     * @see #text(String,String,String)
+     */
+    public String text (String name)
+    {
+        return text(name, "", "");
+    }
+
+    /**
+     * Creates a text input field with the specified name and the
+     * specified extra arguments with no default value.
+     *
+     * @see #text(String,String,String)
+     */
+    public String text (String name, String extra)
+    {
+        return text(name, extra, "");
+    }
+
+    /**
+     * Creates a text input field with the specified name, extra arguments
+     * and default value. For example, a call to <code>text("foo",
+     * "size=\"5\" maxLength=\"8\"", "bar")</code> would result in an
+     * input field looking like:
+     *
+     * <pre>
+     * &lt;input type="text" name="foo" value="bar" size="5" maxLength="8"&gt;
+     * </pre>
+     *
+     * Assuming the <code>foo</code> parameter had no pre-existing value.
+     */
+    public String text (String name, String extra, Object defaultValue)
+    {
+        StringBuffer buf = new StringBuffer();
+        buf.append("<input type=\"text\"");
+        buf.append(" name=\"").append(name).append("\"");
+
+        // fetch the form value, entify it and stick it in
+        buf.append(" value=\"").append(getValue(name, defaultValue));
+        buf.append("\"");
+
+        // append any extra arguments the user may want (maxlength=25
+        // size=10, for example)
+        if (!StringUtil.blank(extra)) {
+            buf.append(" ").append(extra);
+        }
+
+        // close the tag and be done with it
+        buf.append(">");
+        return buf.toString();
+    }
+
+    /**
+     * Constructs a submit element with the specified parameter name and
+     * the specified button text.
+     */
+    public String submit (String name, String text)
+    {
+        StringBuffer buf = new StringBuffer();
+        buf.append("<input type=\"submit\"");
+        buf.append(" name=\"").append(name).append("\"");
+        buf.append(" value=\"").append(text).append("\"");
+        buf.append(">");
+        return buf.toString();
+    }
+
+    /**
+     * Constructs a hidden element with the specified parameter name where
+     * the value is extracted from the appropriate request parameter.
+     */
+    public String hidden (String name)
+    {
+        return hidden(name, "");
+    }
+
+    /**
+     * Constructs a hidden element with the specified parameter name where
+     * the value is extracted from the appropriate request parameter
+     * unless there is no value in which case the supplied default value
+     * is used.
+     */
+    public String hidden (String name, Object defaultValue)
+    {
+        return fixedHidden(name, getValue(name, defaultValue));
+    }
+
+    /**
+     * Constructs a fixed hidden element with the specified parameter name
+     * and value. The contents of the parameter of the same name are
+     * ignored when creating this element.
+     */
+    public String fixedHidden (String name, String value)
+    {
+        StringBuffer buf = new StringBuffer();
+        buf.append("<input type=\"hidden\"");
+        buf.append(" name=\"").append(name).append("\"");
+        buf.append(" value=\"").append(value).append("\"");
+        buf.append(">");
+        return buf.toString();
+    }
+
+    /**
+     * Fetches the requested value from the servlet request and entifies
+     * it appropriately.
+     */
+    protected String getValue (String name, Object defaultValue)
+    {
+        String value = ParameterUtil.getParameter(_req, name, true);
+        if (StringUtil.blank(value)) {
+            value = String.valueOf(defaultValue);
+        }
+        return HTMLUtil.entify(value);
+    }
+
+    /** A reference to the servlet request in use by this form tool. */
+    protected HttpServletRequest _req;
+}