IfTag.java, IfConditionTag.java, IfThenTag.java, and IfElseTag.java, Custom tags that make use of tag nesting
IfTag.java
package cwp.tags;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import javax.servlet.*;
/** A tag that acts like an if/then/else.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class IfTag extends TagSupport {
private boolean condition;
private boolean hasCondition = false;
public void setCondition(boolean condition) {
this.condition = condition;
hasCondition = true;
}
public boolean getCondition() {
return(condition);
}
public void setHasCondition(boolean flag) {
this.hasCondition = flag;
}
/** Has the condition field been explicitly set? */
public boolean hasCondition() {
return(hasCondition);
}
public int doStartTag() {
return(EVAL_BODY_INCLUDE);
}
}
package cwp.tags;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import javax.servlet.*;
/** The condition part of an if tag.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class IfConditionTag extends BodyTagSupport {
public int doStartTag() throws JspTagException {
IfTag parent =
(IfTag)findAncestorWithClass(this, IfTag.class);
if (parent == null) {
throw new JspTagException("condition not inside if");
}
return(EVAL_BODY_TAG);
}
public int doAfterBody() {
IfTag parent =
(IfTag)findAncestorWithClass(this, IfTag.class);
String bodyString = getBodyContent().getString();
if (bodyString.trim().equals("true")) {
parent.setCondition(true);
} else {
parent.setCondition(false);
}
return(SKIP_BODY);
}
}
package cwp.tags;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import javax.servlet.*;
/** The else part of an if tag.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class IfElseTag extends BodyTagSupport {
public int doStartTag() throws JspTagException {
IfTag parent =
(IfTag)findAncestorWithClass(this, IfTag.class);
if (parent == null) {
throw new JspTagException("else not inside if");
} else if (!parent.hasCondition()) {
String warning =
"condition tag must come before else tag";
throw new JspTagException(warning);
}
return(EVAL_BODY_TAG);
}
public int doAfterBody() {
IfTag parent =
(IfTag)findAncestorWithClass(this, IfTag.class);
if (!parent.getCondition()) {
try {
BodyContent body = getBodyContent();
JspWriter out = body.getEnclosingWriter();
out.print(body.getString());
} catch(IOException ioe) {
System.out.println("Error in IfElseTag: " + ioe);
}
}
return(SKIP_BODY);
}
}
package cwp.tags;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import javax.servlet.*;
/** The then part of an if tag.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class IfThenTag extends BodyTagSupport {
public int doStartTag() throws JspTagException {
IfTag parent =
(IfTag)findAncestorWithClass(this, IfTag.class);
if (parent == null) {
throw new JspTagException("then not inside if");
} else if (!parent.hasCondition()) {
String warning =
"condition tag must come before then tag";
throw new JspTagException(warning);
}
return(EVAL_BODY_TAG);
}
public int doAfterBody() {
IfTag parent =
(IfTag)findAncestorWithClass(this, IfTag.class);
if (parent.getCondition()) {
try {
BodyContent body = getBodyContent();
JspWriter out = body.getEnclosingWriter();
out.print(body.getString());
} catch(IOException ioe) {
System.out.println("Error in IfThenTag: " + ioe);
}
}
return(SKIP_BODY);
}
}
Note: Brought from our old site: http://www.salearningschool.com/example_codes/ on Jan 2nd, 2017 From: http://sitestree.com/?p=10286
Categories:Programming Code Examples, Java/J2EE/J2ME, Applets and Basic Graphics
Tags:Java/J2EE/J2MEApplets and Basic Graphics
Post Data:2017-01-02 16:04:31
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