InputTextTag.java

/* Copyright 2005-2006 Tim Fennell
 *
 * Licensed 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 net.sourceforge.stripes.tag;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTag;

import net.sourceforge.stripes.action.ActionBean;
import net.sourceforge.stripes.exception.StripesJspException;
import net.sourceforge.stripes.validation.Validate;
import net.sourceforge.stripes.validation.ValidationMetadata;

/**
 * <p>Tag that generates HTML form fields of type
 * {@literal <input type="text" name="foo" value="bar"/>}, which can dynamically re-populate their
 * value. Text tags may have only a single value, whose default may be set using either the body
 * of the tag, or using the value="" attribute of the tag. At runtime the contents of the
 * text field are determined by looking for the first non-null value in the following list:</p>
 *
 * <ul>
 *   <li>A value with the same name in the HttpServletRequest</li>
 *   <li>A value on the ActionBean if an ActionBean instance is present</li>
 *   <li>The contents of the body of the tag</li>
 *   <li>The value attribute of the tag</li>
 * </ul>
 *
 * @author Tim Fennell
 */
 public class InputTextTag extends InputTagSupport implements BodyTag {
    private Object value;
    private String maxlength;

    /** Basic constructor that sets the input tag's type attribute to "text". */
    public InputTextTag() {
        getAttributes().put("type", "text");
    }

    /** Sets the default value of the text field (if no body is present). */
    public void setValue(Object value) { this.value = value; }

    /** Returns the value set using setValue(). */
    public Object getValue() { return this.value; }


    /** Sets the HTML attribute of the same name. */
    public void setMaxlength(String maxlength) { this.maxlength = maxlength; }

    /** Gets the HTML attribute of the same name. */
    public String getMaxlength() { return maxlength; }

    /**
     * Gets the maxlength value that is in effect for this tag, as determined by checking
     * {@link #getMaxlength()} and then the {@code maxlength} element of the {@link Validate}
     * annotation on the associated {@link ActionBean} property.
     * 
     * @throws StripesJspException if thrown by {@link #getValidationMetadata()}
     */
    protected String getEffectiveMaxlength() throws StripesJspException {
        if (getMaxlength() == null) {
            ValidationMetadata validation = getValidationMetadata();
            if (validation != null && validation.maxlength() != null)
                return validation.maxlength().toString();
            else
                return null;
        }
        else {
            return getMaxlength();
        }
    }

    /**
     * Sets type input tags type to "text".
     * @return EVAL_BODY_BUFFERED in all cases.
     */
    @Override
    public int doStartInputTag() throws JspException {
        return EVAL_BODY_BUFFERED;
    }

    /** Does nothing. */
    public void doInitBody() throws JspException { }

    /**
     * Does nothing.
     * @return SKIP_BODY in all cases.
     */
    public int doAfterBody() throws JspException {
        return SKIP_BODY;
    }

    /**
     * Determines which source is applicable for the value of the text field and then writes
     * out the tag.
     *
     * @return EVAL_PAGE in all cases.
     * @throws JspException if the enclosing form tag cannot be found, or output cannot be written.
     */
    @Override
    public int doEndInputTag() throws JspException {
        // Find out if we have a value from the PopulationStrategy
        Object value = getSingleOverrideValue();

        // Figure out where to pull the value from
        if (value != null) {
            getAttributes().put("value", format(value));
        }

        set("maxlength", getEffectiveMaxlength());
        writeSingletonTag(getPageContext().getOut(), "input");

        // Restore the original state before we mucked with it
        getAttributes().remove("value");

        return EVAL_PAGE;
    }
}