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package com.sun.faces.facelets.el;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ExpressionFactory;
import javax.el.ValueExpression;
import javax.faces.context.ResponseWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;
/**
* Handles parsing EL Strings in accordance with the EL-API Specification. The
* parser accepts either <code>${..}</code> or <code>#{..}</code>.
*
* @author Jacob Hookom
* @version $Id$
*/
public class ELText {
private static final class LiteralValueExpression extends ValueExpression {
/**
*
*/
private static final long serialVersionUID = 1L;
private final String text;
public LiteralValueExpression(String text) {
this.text = text;
}
public boolean isLiteralText() {
return false;
}
public int hashCode() {
return 0;
}
public String getExpressionString() {
return this.text;
}
public boolean equals(Object obj) {
return false;
}
public void setValue(ELContext context, Object value) {
}
public boolean isReadOnly(ELContext context) {
return false;
}
public Object getValue(ELContext context) {
return null;
}
public Class getType(ELContext context) {
return null;
}
public Class getExpectedType() {
return null;
}
}
private static final class ELTextComposite extends ELText {
private final ELText[] txt;
public ELTextComposite(ELText[] txt) {
super(null);
this.txt = txt;
}
public void write(Writer out, ELContext ctx) throws ELException,
IOException {
for (int i = 0; i < this.txt.length; i++) {
this.txt[i].write(out, ctx);
}
}
public void writeText(ResponseWriter out, ELContext ctx)
throws ELException, IOException {
for (int i = 0; i < this.txt.length; i++) {
this.txt[i].writeText(out, ctx);
}
}
public String toString(ELContext ctx) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < this.txt.length; i++) {
sb.append(this.txt[i].toString(ctx));
}
return sb.toString();
}
/*
* public String toString(ELContext ctx) { StringBuffer sb = new
* StringBuffer(); for (int i = 0; i < this.txt.length; i++) {
* sb.append(this.txt[i].toString(ctx)); } return sb.toString(); }
*/
public String toString() {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < this.txt.length; i++) {
sb.append(this.txt[i].toString());
}
return sb.toString();
}
public boolean isLiteral() {
return false;
}
public ELText apply(ExpressionFactory factory, ELContext ctx) {
int len = this.txt.length;
ELText[] nt = new ELText[len];
for (int i = 0; i < len; i++) {
nt[i] = this.txt[i].apply(factory, ctx);
}
return new ELTextComposite(nt);
}
}
private static final class ELTextVariable extends ELText {
private final ValueExpression ve;
public ELTextVariable(ValueExpression ve) {
super(ve.getExpressionString());
this.ve = ve;
}
public boolean isLiteral() {
return false;
}
public ELText apply(ExpressionFactory factory, ELContext ctx) {
return new ELTextVariable(factory.createValueExpression(ctx,
this.ve.getExpressionString(), String.class));
}
public void write(Writer out, ELContext ctx) throws ELException,
IOException {
Object v = this.ve.getValue(ctx);
if (v != null) {
out.write((String) v);
}
}
public String toString(ELContext ctx) throws ELException {
Object v = this.ve.getValue(ctx);
if (v != null) {
return v.toString();
}
return null;
}
public void writeText(ResponseWriter out, ELContext ctx)
throws ELException, IOException {
Object v = this.ve.getValue(ctx);
if (v != null) {
out.writeText((String) v, null);
}
}
}
protected final String literal;
public ELText(String literal) {
this.literal = literal;
}
/**
* If it's literal text
*
* @return true if the String is literal (doesn't contain <code>#{..}</code>
* or <code>${..}</code>)
*/
public boolean isLiteral() {
return true;
}
/**
* Return an instance of <code>this</code> that is applicable given the
* ELContext and ExpressionFactory state.
*
* @param factory
* the ExpressionFactory to use
* @param ctx
* the ELContext to use
* @return an ELText instance
*/
public ELText apply(ExpressionFactory factory, ELContext ctx) {
return this;
}
/**
* Allow this instance to write to the passed Writer, given the ELContext
* state
*
* @param out
* Writer to write to
* @param ctx
* current ELContext state
* @throws ELException
* @throws IOException
*/
public void write(Writer out, ELContext ctx) throws ELException,
IOException {
out.write(this.literal);
}
public void writeText(ResponseWriter out, ELContext ctx)
throws ELException, IOException {
out.writeText(this.literal, null);
}
/**
* Evaluates the ELText to a String
*
* @param ctx
* current ELContext state
* @throws ELException
* @return the evaluated String
*/
public String toString(ELContext ctx) throws ELException {
return this.literal;
}
public String toString() {
return this.literal;
}
/**
* Parses the passed string to determine if it's literal or not
*
* @param in
* input String
* @return true if the String is literal (doesn't contain <code>#{..}</code>
* or <code>${..}</code>)
*/
public static boolean isLiteral(String in) {
ELText txt = parse(in);
return txt == null || txt.isLiteral();
}
/**
* Factory method for creating an unvalidated ELText instance. NOTE: All
* expressions in the passed String are treated as
* {@link com.sun.faces.facelets.el.ELText.LiteralValueExpression}
*
* @param in
* String to parse
* @return ELText instance that knows if the String was literal or not
* @throws javax.el.ELException
*/
public static ELText parse(String in) throws ELException {
return parse(null, null, in);
}
/**
* Factory method for creating a validated ELText instance. When an
* Expression is hit, it will use the ExpressionFactory to create a
* ValueExpression instance, resolving any functions at that time. <p/>
* Variables and properties will not be evaluated.
*
* @param fact
* ExpressionFactory to use
* @param ctx
* ELContext to validate against
* @param in
* String to parse
* @return ELText that can be re-applied later
* @throws javax.el.ELException
*/
public static ELText parse(ExpressionFactory fact, ELContext ctx, String in)
throws ELException {
char[] ca = in.toCharArray();
int i = 0;
char c = 0;
int len = ca.length;
int end = len - 1;
boolean esc = false;
int vlen = 0;
StringBuffer buff = new StringBuffer(128);
List text = new ArrayList();
ELText t = null;
ValueExpression ve = null;
while (i < len) {
c = ca[i];
if ('\\' == c) {
esc = !esc;
if (esc && i < end && (ca[i + 1] == '$' || ca[i + 1] == '#')) {
i++;
continue;
}
} else if (!esc && ('$' == c || '#' == c)) {
if (i < end) {
if ('{' == ca[i + 1]) {
if (buff.length() > 0) {
text.add(new ELText(buff.toString()));
buff.setLength(0);
}
vlen = findVarLength(ca, i);
if (ctx != null && fact != null) {
ve = fact.createValueExpression(ctx, new String(ca,
i, vlen), String.class);
t = new ELTextVariable(ve);
} else {
t = new ELTextVariable(new LiteralValueExpression(
new String(ca, i, vlen)));
}
text.add(t);
i += vlen;
continue;
}
}
}
esc = false;
buff.append(c);
i++;
}
if (buff.length() > 0) {
text.add(new ELText(buff.toString()));
buff.setLength(0);
}
if (text.size() == 0) {
return null;
} else if (text.size() == 1) {
return (ELText) text.get(0);
} else {
ELText[] ta = (ELText[]) text.toArray(new ELText[text.size()]);
return new ELTextComposite(ta);
}
}
private static int findVarLength(char[] ca, int s) throws ELException {
int i = s;
int len = ca.length;
char c = 0;
int str = 0;
while (i < len) {
c = ca[i];
if ('\\' == c && i<len-1) {
i++;
} else if ('\'' == c || '"' == c) {
if (str == c) {
str = 0;
} else {
str = c;
}
} else if (str == 0 && ('}' == c)) {
return i - s + 1;
}
i++;
}
throw new ELException("EL Expression Unbalanced: ... "
+ new String(ca, s, i - s));
}
}